General Salvage and Reconditioning Techniques {0374, 1000} Caterpillar

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Introduction

Table 1

Revision	Summary of Changes in SEBF8148
20	Added new serial number prefixes.
19	Updated surface texture section.
18	Added "References" Section Added "Measurement Techniques" Section Added "Tooling and Equipment" Section Updated "Crack Detection Methods" Section Updated Penetrant Inspection images Added new serial number prefixes.
13 - 17	Added new serial number prefixes.

© 2019 Caterpillar All Rights Reserved. This guideline is for the use of Cat dealers only. Unauthorized use of this document or the proprietary processes therein without permission may be violation of intellectual property law.

Information contained in this document is considered Caterpillar: Confidential Yellow.

This Reuse and Salvage Guideline contains the necessary information to allow a dealer to establish a parts reusability program. Reuse and salvage information enables Caterpillar dealers and customers to benefit from cost reductions. Every effort has been made to provide the most current information that is known to Caterpillar. Continuing improvement and advancement of product design might have caused changes to your product which are not included in this publication. This Reuse and Salvage Guideline must be used with the latest technical information that is available from Caterpillar.

For technical questions when using this document, work with your Dealer Technical Communicator (TC).

To report suspected errors, inaccuracies, or suggestions regarding the document, submit a form for feedback in the Service Information System (SIS Web) interface.

Important Safety Information

Illustration 1	g02139237

Work safely. Most accidents that involve product operation, maintenance, and repair are caused by failure to observe basic safety rules or precautions. An accident can often be avoided by recognizing potentially hazardous situations before an accident occurs. A person must be alert to potential hazards. This person should also have the necessary training, skills, and tools to perform these functions properly. Safety precautions and warnings are provided in this instruction and on the product. If these hazard warnings are not heeded, bodily injury or death could occur to you or to other persons. Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard. Therefore, the warnings in this publication and the warnings that are on the product are not all inclusive. If a tool, a procedure, a work method, or operating technique that is not recommended by Caterpillar is used, ensure it is safe for you and for other people to use. Ensure that the product will not be damaged or will not be made unsafe by the operation, lubrication, maintenance, or the repair procedures used.

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Improper operation, lubrication, maintenance or repair of this product can be dangerous and could result in injury or death. Do not operate or perform any lubrication, maintenance or repair on this product, until you have read and understood the operation, lubrication, maintenance and repair information.

Safety precautions and warnings are provided in this manual and on the product. If these hazard warnings are not heeded, bodily injury or death could occur to you or to other persons.

The hazards are identified by the safety alert symbol which is followed by a signal word such as danger, warning, or caution. The "WARNING" safety alert symbol is shown below.

Illustration 2	g00008666

This safety alert symbol means:

Pay attention!

Become alert!

Your safety is involved.

The message that appears under the safety alert symbol explains the hazard.

Operations that may cause product damage are identified by "NOTICE" labels on the product and in this publication.

Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard. The safety information in this document and the safety information on the machine are not all inclusive. Determine that the tools, procedures, work methods, and operating techniques are safe. Determine that the operation, lubrication, maintenance, and repair procedures will not damage the machine. Also, determine that the operation, lubrication, maintenance, and repair procedures will not make the machine unsafe.

The information, the specifications, and the illustrations that exist in this guideline are based on information which was available at the time of publication. The specifications, torques, pressures, measurements, adjustments, illustrations, and other items can change at any time. These changes can affect the service that is given to the product. Obtain the complete, most current information before you start any job. Caterpillar dealers can supply the most current information.

Summary

Caterpillar has issued many Reuse and Salvage Guidelines, and various other publications for the salvage, modification, and repair of specific components. This guideline describes:

• Measurement techniques

• Various repair and salvage methods.

• When and how the salvage methods can be applied to Caterpillar components not covered by other publications or specific guidelines.

• Machine shop practices

• Several methods of detecting cracks before and after parts are repaired or salvaged.

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NOTICE
Some components are unacceptable for salvage or reconditioning due to the application, heat treatment, or metallurgy. These components are not covered by this publication or any other publication.

References

Table 2

References
Media Number	Publication Type & Title
Channel1	"Gear Tooth Inspection"
	https://channel1.mediaspace.kaltura.com/media/Gear+Tooth+Inspection/1_5ujdi5zp
	"Why Reuse and Salvage Parts"
	https://channel1.mediaspace.kaltura.com/media/Why+Reuse+and+Salvage+Parts/0_ae9rhu2z
REHS2133	Reuse and Salvage"Cylinder Block Salvage Procedure for Using Belzona® 1311 (Ceramic R Metal)"
SEBD0512	Reuse and Salvage Guidelines "Caterpillar Service Welding Guide"
SEBF8187	Reuse and Salvage Guidelines "Standardized Parts Marking Procedures"
SEBF8357	Reuse and Salvage Guidelines "General Cleaning Methods"
SEBF8728	Reuse and Salvage Guidelines "Specifications for Inspection of Driveline Fasteners"
SEBF8882	Reuse and Salvage Guidelines "Using Lock-N-Stitch Procedures for Casting Repair"
SEBF9236	Reuse and Salvage Guidelines "Fundamentals of High Velocity Oxygen Fuel (HVOF) Spray for reconditioning Components" (1)
SEBF9238	Reuse and Salvage Guidelines "Fundamentals of Arc Spray for reconditioning Components" (1)
SEBF9240	Reuse and Salvage Guidelines "Fundamentals of Flame Spray for Reconditioning Components" (1)
SEHS8792	Special Instruction "Using Caterpillar Replacement Thread Inserts"
SEHS8919	Reuse and Salvage Guidelines "Reuse and Salvage for Cast Iron Cylinder Blocks"

(1)	Only Cat dealers may utilize applications for Thermal Spray. The processes must be carried out within the facilities of the dealership. The dealership must maintain a clean environment and always use the correct equipment for all processes in each Thermal Spray Application.

Service Advisories, Service Letters, and Technical Information Bulletins

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NOTICE
The most recent Service Advisories and Service Letters that are related to this component should be reviewed before beginning work. Often Service Advisories, Service Letters, and Technical Information Bulletins contain upgrades in repair procedures, parts, and safety information which pertain to the components being repaired.

Canceled Part Numbers and Replaced Part Numbers

This document may include canceled part numbers and replaced part numbers. Use the Numerical Part Record (NPR) on the Service Information System Website (SIS web) for information about canceled part numbers and replaced part numbers. NPR will provide the current part numbers for replaced parts.

Tooling and Equipment

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NOTICE
Failure to follow the recommended procedure or the specified tooling that is required for the procedure could result in damage to components. To avoid component damage, follow the recommended procedure using the recommended tools.

Table 3

Required Tooling and Equipment
Part Number	Description	Qty
1U-5516	Disc (Coarse)	As needed
1U-5518	Shaft, Threaded	As needed
1U-5519	Disc Pad Holder	As needed
1U-9366	Automatic Tape Measure	1
1U-9915	Curved Handle Wire Brush	1
4C-3770	Grinding Wheels	As needed
4C-4804	Penetrant	As needed
4C-5823	Heating Torch Handle	As needed
4C-5830	Heating Torch Mixer	As needed
4C-5831	Tip Tube	As needed
4C-8514	Flapper Wheel (2" x 1" 60 grit)	As needed
4C-8515	Flapper Wheel (2" x 1" 120 grit)	As needed
4C-9442	Flashlight	As needed
4C-9619	Welding Blanket	As needed
4S-9405	Caliper	1
5P-3920	Steel Ruler	1
5P-7414	Seal Pick	1
6V-2010	Polishing Stone	1
6V-6035	Hardness Tester, Leeb Style	As needed
8H-8581	Feeler Gauge	As needed
8S-2257	Eye Loupe	As needed
8T-5096	Dial Indicator Group	1
8T-7765	Surface Reconditioning Pad	As needed
9A-1593	Comparison Gauge	As needed
9S-8903	Indicator Contact Point	1
9U-6182	Inspection Mirror	1
173-0531	Sealant Kit	As needed
222-3071	Portable Angle Grinder Group	As needed
222-3074	Wheel Grinder Group	As needed
222-3076	Die Grinder (RIGHT ANGLE)	As needed
222-3080	Air Hammer	As needed
223-4356	Weld Breaker	As needed
236-8097	Carbide Burr	As needed
237-5181	Respirator	As needed
254-5319	Surface Condition Brush	As needed
262-8390	Microscope, Pocket 40x	As needed
263-7184	Crack Detection Kit	1
288-4209	Paper Towel	As needed
349-4202	Infrared and Contact Thermometer 12:1 Ratio	As needed
367-9109	Digital Caliper	1
385-8484	Level 305 mm (12 inch)	As needed
385-4008	Micrometer Tool Set, External 1524 mm (60 inch)	1
385-9422	Micrometer Extensions, Internal 50 - 609 mm (2 - 24 inch)	1
386-3364	Straight Edge	As needed
415-4055	Ultrasonic Tool Group	As needed
420-5317	Tool Cribbing	As needed
423-4373	Digital Caliper 0.0 - 203.2 mm (0.00 - 8.00 inch)	As needed
431-4150	Micrometer, External 25 mm (1 inch)	1
459-0184	UV Lamp Group	As needed
473-8688 or 473-8689	Micrometer, Inside 2.00 - 12.00 inch	1
	Micrometer, Inside 50 - 300 mm	1
473-8690	Micrometer, Outside 0.00 - 4.00 inch	1
473-8691	Micrometer, Outside 2.00 - 6.00 inch	1
473-8691	Micrometer, Outside 50.8 - 152.4 mm (2.00 - 6.00 inch)	As needed
473-8692	Micrometer, Outside 152.4 - 304.8 mm (6.00 - 12.00 inch)	As needed
474-3709 or 474-3710	Micrometer, Inside (8.00 - 32.00 inch)	As needed
	Micrometer, Inside 200 - 800 mm	As needed
477-3166 (1)	Portable Boring Bar (110 v)	As needed
477-3167 (1)	Portable Boring Bar (240 v)	As needed
477-3189	Bore Welding System	As needed
-	Bright Incandescent Light	1
-	Carbon Arc Gouging Torch	As needed
-	Clevis	As needed
-	Compound	1
-	Developer	As needed
-	GO/NO-GO Thread Gauge Set, Metric	1
-	GO/NO-GO Thread Gauge Set, SAE	1
-	Lifting Eye Assemblies	As needed
-	Oxy-Propane Kit	1
-	Plasma Arc Gouging Torch	As needed
-	Plastic Plug Assortment	As needed
-	Quick Cure Primer	As needed
-	Retaining Compound	As needed
-	Suitable Lifting Device	As needed
-	Tap and Die Set	1

(1)	Various bar lengths and extra Tooling are available through Dealer Service Tools.

Measurement Techniques

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NOTICE
Precise measurements shall be made when the component and measurement equipment are at 20°C (68°F). Measurements shall be made after both the component and measurement equipment have had sufficient time to soak at 20°C (68°F). This will ensure that both the surface and core of the material are at the same temperature.

Preparation Recommendations

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Personal injury can result when using cleaner solvents. To help prevent personal injury, follow the instructions and warnings on the cleaner solvent container before using.

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Personal injury can result from air pressure. Personal injury can result without following proper procedure. When using pressure air, wear a protective face shield and protective clothing. Maximum air pressure at the nozzle must be less than 205 kPa (30 psi) for cleaning purposes.

Illustration 3	g03794147
Typical burr removal tooling. (A) Die grinder/right angle (B) Wheel Grinder Group (C) Conditioning discs, disc pad holder, and threaded shaft (D) Flapper wheel

• Before you inspect a component, clean thoroughly to ensure that all components are free from rust, oil, burrs, and debris prior to inspection. A surface irregularity can hide the indication of an unacceptable defect.

• Use a proper lifting device to provide safety to the operator. Also, use a proper lifting device to prevent damage to the part when you lift the part.

• During cleaning, do not damage machined surfaces.

• Do not use pressurized air to dry internal components. Compressed air has moisture and contaminants that can cause premature failure of internal components.

• Put hydraulic oil on all machined surfaces to prevent rust or corrosion if inspection is not done immediately after cleaning. Carefully store the parts in a clean container.

• Inspect all flange mating surfaces for fretting. Ensure that flange mating surfaces are true and free from raised material resulting from rust, nicks, and dents.

• Use appropriate thread taps to chase all threaded holes.

Illustration 4	g03794153
(E) Typical example of chasing threaded holes.

Illustration 5	g06001315
Typical example of checking threaded holes using GO/NO-GO Thread Gauges.

Inspect all threaded holes with appropriate Go/No-Go Thread Gauges.

Note: NO-GO Thread Gauge (F) can be screwed into threaded hole no more than two turns. For acceptance of part, GO Thread Gauge (G) should pass through the entire length of the threaded hole without requiring too much rotational force.

If NO-GO Thread Gauge (F) exceeds two turns, then repair threads. Refer to SEHS8792Special Instruction, "Using Caterpillar Replacement Thread Inserts".

Measurement Tooling Calibration

Micrometers

Illustration 6	g03735896

Measurement Tooling include precision inside and outside diameter micrometers capable of measuring four decimal places in inches or three decimal places in millimeters. Measuring tools should be calibrated using gauge blocks certified to a national standard such as the National Institute of Standards and Technology (NIST).

Straight Edge

Illustration 7	g03822876
Example of checking flatness of a straight edge (C) using a precision granite flatness plate (E). (C) Straight Edge (D) Hole (E) Granite Toolmaker's Flat

Note: Storage of a straight edge is crucial to ensuring that it remains true.

• Cover the machined surface of the straight edge.

• Hang straight edge vertically using hole (D).

Bore Diameters

Illustration 8	g06085430
Typical example of measuring Inside Dimension (ID) of a bore .

Note: Measurements taken on the edge of a bore may not give an accurate measurement.

Take measurements at locations (A1), (A2), and (A3).

Then take measurements at locations (A4), (A5), and (A6).

To ensure adequate life of the components, this document contains precise tolerances for measurements taken on various features. Ensure that several sample measurements are taken at different locations on the same feature. Measure diameters of internal bores in six places to identify tapered and or oval conditions. Refer to Illustrations 8,9, and 10.

Illustration 9	g06001444
Typical example of measuring a large bore.

Illustration 10	g03772954
Typical example of measuring the small bore.

Shaft and Journal Diameters

Illustration 11	g06068348
Typical example of measuring an Outside Diameter (OD) Dimension. To obtain the Dimension (F), measure the distance between Locations (D) and (E). (C) Indicates the diameter of the shaft. (D) Shoulder of the shaft. (E) End of the shaft. (F) Indicates 25% of the overall length of the shaft.

Note: Measurements taken on the edge of a shaft may not give an accurate measurement.

Take measurements at locations (C1), (C2), and (C3).

Then take measurements at locations (C4), (C5), and (C6).

To ensure adequate life of the components, this document contains precise tolerances for measurements taken on various features. Ensure that several sample measurements are taken at different locations on the same feature. Measure diameters of external shafts/ journals in six places to identify tapered and or oval conditions. Refer to Illustration 11.

Illustration 12	g03735958
Typical example of measuring the OD of a labyrinth sealing ring.

Internal Splines / Teeth

Gage pins are available to order, if size is not available, the pins can be made. Care must be taken to precisely machine these pins to specification due to the close tolerances of the pin diameters. If these pins are to be made, the use of 52100 alloy steel is recommended. These gage pins are Class ZZ and have an allowed deviation of 0.00508 mm (0.0002 inch), geometry of 0.00254 mm (0.0001 inch), and a surface texture of 0.2540 µm (10.000 µin) Ra. Each pin must be machined for each individual spline set according to specified dimensions.

Illustration 13	g06075213
Typical example of taking an internal spline measurement.

Illustration 14	g06085434
(G), (H), and (J) Measurement Locations

Take measurements at locations (G), (H), and (J) between gage pins at 60° intervals. The location of the gage pins at 60° intervals is critical to the formula. These three locations will provide information about the wear of the part. Refer to Illustration 14.

An inside micrometer must be positioned to measure the shortest distance points on the gage pins. This procedure will provide the measurement of the wear on the spline/ tooth. The gage pin diameter for each individual part is determined by the size and pitch of the spline/ tooth.

Calculate the average of the values taken from locations (G), (H), and (J). The difference between the measurements will determine if there is an out of round condition caused by poor load distribution on the splines/ teeth.

External Splines / Teeth

Illustration 15	g06075290
Typical example of taking a Measurement Over Pins (MOP).

Illustration 16	g06085436
(K), (L), and (M) measurement locations

Take measurements at locations (K), (L), and (M) over gage pins.

Note: The location of gage pins at 60° intervals is critical to the formula. These three locations will provide information about the wear of the part.

Place gage pins at 60° intervals on the gear tooth/ spline. Take the measurements over gage pins that are located approximately 180° away from each other.

Note: For odd tooth/ spline gears take measurement as close to 180° from each gage pin as possible.

A micrometer must be positioned to measure the highest external points on the gage pins. This procedure will provide the measurement of the wear of the gear tooth/ spline. The gage pin diameter for each individual part is determined by the size and pitch of the gear tooth/ spline. Calculate the average from the values taken. The difference between the measurements will determine if there is an out of round condition caused by poor load distribution on the gear teeth/ splines.

Methods of Securing Gage Pins

Illustration 17	g06075262
Typical example of MOP. (N) Rubber Band (P) Gage Pins

Note: Rubber band (N) or a bungee strap can be used to secure gage pins (P) in place when taking measurements of external splines. Refer to Illustration 17.

Illustration 18	g06124082
Typical example of a magnetizer/ demagnetizer.

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NOTICE
If gage pins are magnetized, then demagnetize after use. When a gage pin is magnetized, cuttings and iron powder will easily stick to the surface, thus precipitating wear.

Gage pins can be magnetized to aid in taking measurements between or over gauge pins. Ensure that gauge pins are demagnetized after use and stored properly.

Illustration 19	g06075285
Typical example of taking a Measurement Over Pins (MOP). (R) Gage Pin (S) Magnet

Note: Magnets (S) are another method that can be used to keep gage pins (R) in place when taking measurements. Refer to Illustration 19.

Gear Tooth Span Method

Illustration 20	g06123902
Typical example of taking gear tooth span measurement (T). (T) Gear Tooth Span Measurement

Illustration 21	g06123897
(U), (V), and (W) Measurement Locations

Take measurements at locations (U), (V), and (W). If necessary take measurements at secondary locations (U1), (V1), and (W1).

Measure required span of gear tooth / spline at 120° intervals from center of gear tooth span to center of next gear tooth span. A micrometer must be positioned, as shown in Illustration 21. This procedure will provide the measurement of the wear of the gear tooth. The number of teeth for each individual part is determined by the size and pitch of the gear tooth. Detailed information is located in a table following each gear within this document. Calculate the average from the values taken.

Standardized Parts Marking Procedure

Reference: , SEBF8187Reuse and Salvage Guidelines, "Standardized Parts Marking Procedures".

The code is a Cat standard and is used to record the history of a component. The code will identify the number of rebuilds and hours at the time of each rebuild. This information is important and should be considered for any decision to reuse a component.

Ensure that the mark is not covered by a mating part. Use a metal marking pen to mark the code onto the component.

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NOTICE
Do not use numbering stamp punches to mark internal components. The impact from striking the stamp will cause an abnormal stress riser. The added stress riser may cause premature part failure.

Illustration 22	g06124077
DO NOT use numbering stamp punches to mark internal components.

The procedure for marking components is a Cat standard. This code is helpful when the machine is sold into a different territory after the first rebuild. During an overhaul, the previous code of a part should never be removed.

Example 1

Illustration 23	g03856853
Typical Example

Illustration 23 shows code (1-15). The first number (1) indicates that the gear had been rebuilt once. The second number (15) indicates that there were 15,000 hours on the gear at the time of rebuild.

Example 2

Illustration 24	g03856857
Typical Example

Illustration 24 shows code (1-12) and code (2-10). Code (2-10) represents the information from the second rebuild. The first number (2) indicates that the gear had been rebuilt twice. The second number (10) indicates that 10,000 hours accumulated on the gear between the first and second rebuild.

Note: Add the first and second rebuild hours to obtain the total number of hours for the gear in Illustration 24. In this example, the gear has a total of 22,000 hours.

Types of Salvage Procedures

Following are the procedures to salvage:

1. Machine and Sleeve to Manufacturing Specifications

2. Machine Undersize/Oversize

3. Weld and Machine to Manufacturing Specifications

4. Weld (Reference SEBD0512)

5. Thermal Spray and Machine to Manufacturing Specification (Reference SEBF9236, SEBF9238, SEBF9240)

6. Composite Fill

7. Machine, Chrome Plate, and Machine to Manufacturing Specifications

8. Machine and Nickel Plate to Manufacturing Specifications

9. LOCK-N-STITCH Method for Metal Stitching (Reference SEBF8882)

10. Anaerobic Materials

11. LOCK-N-STITCH Full-Torque Thread Inserts

12. Threaded Hole Repair

Typical Applications

Table 4

Typical Applications of Salvage Procedures
Type of Part	Material	Type of Salvage (1)
		1	2	3	4	5	6	7	8	9	10	11	12
Bearing Inner Race Support	Mild Steel	X	−	X	−	X	−	X	X	−	X	−	−
Bearing Outer Race Support	Cast Iron	X	−	X	−	X	−	X	X	−	X	−	−
Worn Dowel Hole	Cast Iron	X	−	X	−	−	−	−	−	−	−	−	−
Worn Seal Ring Bore	Cast Iron	X	X	X	−	X	−	X	X	−	−	−	−
Cracked Housing (Non-structural)	Cast Iron	−	−	−	X	−	X	−	−	−	−	−	−
Cracked Housing	Various	−	−	−	−	−	−	−	−	−	−	X	X
Damaged Tapped Hole	Various	−	−	X	−	−	X	−	−	−	−	X	X

(1)	The "Type of Salvage" number correlates with the salvage procedures in the "Types of Salvage Procedures" Section.

Selecting Procedure

As Table 4 indicates, there may be more than one acceptable salvage method that best fits your machine shop equipment. Sometimes, characteristics of a specific “Type Of Part” may prevent the use of some options. For example, wear in a seal ring bore may exceed the maximum acceptable diameter. The wear will eliminate the “machine undersize / oversize” option. It may be necessary to remove a small wear step from the ring bore.

Note: Some of the procedures refer to the term “Machine”. Whenever there is a machinery operation, it is important to use good machine shop practices concerning feeds, speeds, size, condition of machine tools, condition of cutting tools and cutting fluids to ensure the successful salvaging of a part. Refer to the “Machine Shop Practices” section.

General Types of Salvage Procedures

1. Machine and Sleeve to Manufacturing Specifications

Description of the Procedure

This salvage procedure consists of machining a shaft or cylindrical bore undersize or oversize, respectively, and installing a sleeve made of a material compatible with the base part.

Application Limitations

Illustration 25	g06087421
Simple Cylindrical Sleeve

Illustration 26	g06087452
Sleeve against a shoulder in the bore

Illustration 27	g06087457
Sleeve with a flange

Illustration 28	g06087464
Sleeve against a shoulder on outer diameter of bore

Do not install simple sleeves, cylindrical sleeves if one end of the sleeve will be subject to the hydraulic pressures or other thrust loads that would tend to push out the sleeve. Such applications require positive retention of the sleeve by pins, weld or set screws. Other methods include incorporating a flange on the sleeve, or either a shoulder in the bore or on the outer diameter of the piece being repaired. Refer to Illustrations 25,26,27, and 28.

This procedure is not recommended for highly stressed bores and highly loaded bores such as loader frames or ripper bores.

Sleeve Material

Whenever possible, material for the sleeves should be similar to the base material. Similar materials will minimize the possibility of the sleeve coming loose during operation because of different expansion rates. Similar materials will also minimize the possibility of corrosion that is induced by electrolysis. Of lesser concern, but still worthy of consideration, is the need to maintain compatibility between mating surfaces to avoid problems such as galling or excessive wear.

Expansion Fit

An “expansion fit” sleeve is one that requires the lowering the temperature of the sleeve, which reduces the outside diameter of the sleeve, to be installed in a bore. When the installed sleeve reaches ambient temperature the sleeve will expand into the bore. The expanded sleeve will create the desired fit. Lowering the temperature may be accomplished with a freezer, do not go below the temperature of −55 °C (−67 °F).

Illustration 29	g03638296
Typical example of dry ice.

Illustration 30	g03638303
Typical example of a freezer.

Shrink Fit

A “shrink fit” sleeve is one that requires the heating of the sleeve, which increases the inside diameter, to install it onto another part. As the sleeve returns to ambient temperature, the sleeve shrinks to the correct fit. Heating may be done with an oil bath or induction type bearing heater, or an oven. The use of a torch is not recommended because of inherent uneven heating, and localized overheating problems.

Illustration 31	g01152304
Typical example of an oven.

Press Fit

A press fit is the interference between the outside diameter of the bearing and the inside diameter of the housing bore. This type of fit is intended to determine the accurate location of the mating parts, and for parts requiring rigidity and alignment with no special requirement for bore pressure. In this type of fit, the sleeve/ bearing should be pressed into the bore not driven in.

Note: It may require lowering and raising temperatures of mating parts before pressing in.

Sleeve Retention

Use the following procedure to insert a simple cylindrical inside diameter sleeve:

1. Be sure that the sleeves and bores are as clean and dry as possible.

2. Apply quick cure primer to the outside diameter of the sleeve and bore.

3. Apply a thin film of Retaining Compound to the outside diameter of the sleeve.

4. Press the sleeve into the bore. Refer to “Expansion Fit” section to lower the temperature of the sleeve.

Use the following procedure to press the simple cylindrical outside diameter sleeve:

1. Be sure that the inside diameter of the sleeve and outside diameter of the shaft are as clean and dry as possible.

2. Apply quick cure primer to the inside diameter of the sleeve and outside diameter of the shaft.

3. Apply a thin film of retaining compound to the outside diameter of the shaft.

4. Press the sleeve onto the shaft. Refer to the “Shrink Fit” section to heat the sleeve. Do not exceed a maximum temperature of 150 °C (302 °F) to heat the sleeve.

Other Sleeve Design Requirements

Outside corners of sleeves and shafts must have a radius or chamfer at least as large as the radius or chamfer on the mating inside corner. Failure to provide such chamfers or radii can result in a sleeve that loosens, and ultimately fails during use. Chamfers or radii also permit the sleeve to be pressed into or onto the part being salvaged without shearing material from the bore or shaft. Lastly, chamfers permit the repaired part to be assembled more easily.

Typical Applications

• Sleeve bearings pressed into heavy section steel or cast iron housings.

• Bores with rotating shafts.

• Repair of reaction dowel holes in transmission clutch housings.

2. Machine Undersize / Oversize

Procedure Description

This salvage procedure consists of machining a surface to remove worn or damaged areas and restoring the original surface texture, but with different finished dimensions. Either the change in size must not affect the function of the part. Or a special service part must be available or fabricated to compensate for the material removed during the salvage operation.

Applications Limitations

Seal ring bores and piston ring bores.

Not all piston/seal ring applications have oversized / undersize rings available. A small amount of material can be removed from the contact face to remove wear grooves or steps. It is important not to exceed the general wear limits listed here.

Typical Applications

• Engine cylinder liner bores. Refer to the appropriate Reuse And Salvage Guidelines, "for reusable parts for permissible wear".

• Transmission clutch piston bores for cast iron seal rings.

• Transmission clutch piston bores for Teflon seal rings.

• Transmission and torque converter housings, cages, and manifolds.

• Crankshafts.

• Camshafts.

• Clutch plates.

• Transmission pistons.

• Hydraulic pump parts.

• Bores and shafts that serve as bearing races. Engineering design does not permit the removal of wear steps.

3. Weld and Machine To Manufacturing Specifications

Procedure Description

This salvage procedure consists of building up worn or damaged surfaces or areas with weld, and machining the weld back to original dimensions. Refer to Reuse And Salvage Guidelines, SEHS8919, "Reuse and Salvage for Cast Iron Cylinder Blocks" for typical cast iron welding procedures.

Application Limitations

• Cast iron and steel require a specific weld. Refer to Reuse And Salvage Guidelines, SEHS8919, "Reuse and Salvage for Cast Iron Cylinder Blocks" for specific procedure.

• Potential for heat-induced warping must be considered.

• Potential for annealing or cracking heat-treated shafts.

Typical Applications

• Seal wear areas.

• Bearing support of the shafts and the bores.

• Worn dowel holes.

• Loader frames and ripper frames.

• Track roller frames.

• Hydraulic cylinder eyes.

4. Weld

Procedure Description

This salvage procedure consists of building up worn or damaged surfaces or areas with weld. The noncritical nature of the “finished dimensions” given for areas of some parts do not require post-weld machining of the weld deposit other than dressing with a hand grinder or rotary file.

Refer to Reuse And Salvage Guidelines, SEBD0512, "Caterpillar Service Welding Guide" for general welding information.

Refer to Reuse And Salvage Guidelines, SEHS8919, "Reuse and Salvage for Cast Iron Cylinder Blocks" for typical cast iron welding procedures.

Application Limitations

• Cast iron and steel require a specific weld. Refer to Reuse And Salvage Guidelines, SEHS8919, "Reuse and Salvage for Cast Iron Cylinder Blocks" for the specific procedure.

• Potential for heat-induced warpage must be considered.

Typical Applications

• Weldable areas damaged by external forces.

• Track rollers, links, and idlers.

• Bucket edges.

• Crankcase guards (belly pans).

5. Thermal Spray and Machine to Manufacturing Specifications

Procedure Description

This salvage procedure consists of machining the worn or damaged surface, then build up the surface with thermal spray, and machining to original dimensions. Thermal spray is not a welding process, but a bonding process by using heat and high velocity particles and does not add any structural strength. Correctly applied thermal spray will not affect the heat treat of the base material. Thermal spray at Caterpillar consists of the following processes:

1. Flame spray is the basic thermal spray process for restoring a surface and is limited to a lower bond strength and hardness of the coating. Refer to Reuse And Salvage Guidelines, SEBF9240, "Fundamentals of Flame Spray for Reconditioning Components"

2. Arc spray provides a higher bond strength and the ability to apply a harder wear resistant coating. Refer to Reuse And Salvage Guidelines, SEBF9238, "Fundamentals of Arc Spray for Reconditioning Components"

3. High Velocity Oxygen Fuel (HVOF) is the thermal spray process that provides the highest bond strength and hardest coating. This process is used to replace chrome plating on cylinder rods. Refer to Reuse And Salvage Guidelines, SEBF9236, "Fundamentals of High Velocity Oxygen Fuel (HVOF) Spray for Reconditioning Components"

Application Limitations

• No impact or point-loading applications currently recommended.

• Quality of coating is dependent upon process control during every step of the salvage procedure.

• No bending applications.

Typical Applications

• Seal wear areas.

• Bearing support of the shafts and the bores.

• Worn dowel holes.

• Bores in housings.

• Cylinder rods and struts (HVOF).

6. Composite Fill

Procedure Description

This salvage procedure consists of building up worn or damaged surfaces or areas with nonmetallic composites. Refer toReuse and Salvage, SEHS8869, "Cylinder Block Salvage Procedure Using Belzona® (Ceramic R Metal)" for typical repair procedures using composite materials.

Application Limitations

• No impact or point-loading applications.

• Quality of coating is dependent upon process control.

• Operational temperature limitations.

Typical Applications

• Cylinder blocks

• Porosity

• Erosion

• Crack repair (non-structural).

7. Machine, Chrome Plate, and Machine to Manufacturing Specifications

Chrome plating is a specialized process. Actual instructions for plating are beyond the scope of this publication.

Procedure Description

This salvage procedure consists of machining worn or damaged outer surfaces undersize, chrome plating, and finish-grinding the surfaces to original dimensions. Although more difficult to do, inside surfaces are sometimes machined oversize, plated, and ground to original dimensions. Chrome plated parts may need to be put into an oven at a temperature of 150 °C (302 °F) for 3 hours to prevent cracking (hydrogen-embrittlement) of the part. The baking must be started within an hour after removal from the plating tank.

Plating thickness can range from 0.005 mm (0.0002 inch) to more than 0.5 mm (0.02 inch), depending on the application.

Application Limitations

• No impact or point-loading applications.

• Quality of coating is dependent upon process control.

• No bending applications.

Typical Applications

• Seal wear areas.

• Bearing support of the shafts and the bores

• Transmission and hydraulic control valve spools

• Hydraulic cylinder rods.

• Bucket and loader pins.

8. Machine and Nickel-Plate to Manufacturing Specifications

Electroless nickel plating is a specialized process. Actual instructions for plating are beyond the scope of this publication.

Procedure Description

Electroless nickel plating, a chemical process, is less common than chrome electroplating, but has certain advantages over chrome. The most important advantage is the ability to plate to exact size and not require a post-plating grinding operation.

Another advantage of electroless nickel plating is the uniformity of the build-up. Corners and unmasked inside diameters will plate at the same rate as the outside surfaces, whereas chrome builds up on sharp edges at a higher rate than on flat, outside surfaces, and inside diameters build up at a slower rate than outside diameters.

The basic salvage procedure consists of machining worn or damaged outer surfaces undersize and plating the surfaces to original dimensions. Although less commonly done (but easier to do than chrome plating), inside surfaces are machined oversize and plated to original dimensions. Care must be taken during pre-machining, as the surface texture of the premachining determines the final surface texture.

Application Limitations

• No impact or point-loading applications.

• Quality of coating is dependent upon process control.

• Build-up thickness is limited to approximately 0.130 - 0.180 mm (0.005 - 0.007 inch).

• Plating build-up is slow, approximately 0.013 mm (0.0005 inch) per hour.

• As plated hardness is Rockwell C 48-52. Hardness after a low temperature 190 °C (374 °F) heat treatment goes up to about Rockwell C 58. Maximum hardness of Rockwell C 65 is reached with a high temperature 370 °C (698 °F) heat treatment. Sometimes light polishing may be required after the high temperature heat treatment.

Typical Applications

• Seal wear areas.

• Bearing support of the shafts and the bores.

• Transmission and hydraulic control valve spools.

9. LOCK-N-STITCHMethod for Metal Stitching

Procedure Description

Metal stitching is a simple concept where the crack is removed and replaced. Metal stitching is done with an overlapping series of stitching pins, with locks installed at intervals along the length of the repair for added strength. The following are the four steps of metal stitching:

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Illustration 32	g02050576

1. Drilling the lock hole pattern.
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   Illustration 33	g02050577

2. Installing the lock.
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   Illustration 34	g02050578

3. Start installing the stitching pins.
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   Illustration 35	g02050579

4. Completed repair is ground flush.

Note: For further information on metal stitching refer to Reuse And Salvage Guidelines, SEBF8882, "Using LOCK-N-STITCH Procedures for Casting Repair".

Application Limitations

Varies depending on parts to repair.

Typical Applications

• Cracked engine cylinder block or cylinder heads

• Transmission case

• Oil pan

10. Anaerobic Materials

Procedure Description

This salvage procedure uses polymers that are self-curing without air to compensate for marginally excessive wear in press fit joints. Materials in this category are found in the 173-0531 Sealant Repair Kit.

Applications Limitations

• Operational temperature limitations.

• Surface cleanliness is important for maximum success.

Typical Applications

• 9S-3265 Retaining Compound usable up to a temperature of 200 °C (392 °F). Restores fit to worn parts such as pins, splines, gears, pulleys, keys, and keyways.

• 7M-7456 Bearing Mount Compound usable up to a temperature of 150° C (302 °F). Restores fit to worn parts, and aids the fit for new parts such as: ball and roller bearing races, cups, and cones, bushings.

11. LOCK-N-STITCH Full-Torque Thread Inserts

Procedure Description

This salvage procedure consists of drilling out the damage threads and tapping new threads, then installing the new Full-Torque insert. What makes this insert different from other thread inserts is the spiral hook threads that only transfer a radial drawing force to the surrounding material. This allows you to repair cracked bolt holes, because the insert will contain the force of the bolt. It also can be used along with the locks and pins to repair cracked castings.

Illustration 36	g02050596
Full- Torque thread repair insert

Note: For further information on Full-Torque thread inserts refer to Reuse And Salvage Guidelines, SEBF8882, "Using LOCK-N-STITCH Procedures for Casting Repair".

Applications Limitations

Some application may have to thin of wall to allow the use of a Full-Torque insert.

Typical Applications

• Any hole with the damaged or cracked threads.

• Ductile iron wheels.

12. Threaded Hole Repair

The selection of an appropriate thread repair method for a given application is determined by several factors.

• Design of the work piece being repaired

• Work piece material - Do not weld on ductile iron

• Type of thread damage being corrected

• Pull-out strength required of the repaired thread

• Physical access to the work piece to accomplish the repair

Table 5

Threaded Hole Repair Method Advantages vs. Disadvantages
Repair Method	Advantages	Disadvantages
Welding Threaded Hole Drill and Tap	- Can result in a repair that is cosmetically and structurally no different than the original material - Most effective in relocating of improperly positioned threaded hole	- Heat distortion during welding is a concern for close-tolerance parts, and for parts with a narrow cross-section design - Some materials may form hard spots during welding which limits the number of materials that are well-suited for this weld-repair process
Replacement Thread Inserts	- Increase strength of an assembly by distributing fastener clamping forces over a larger area of base material - Increase the pull-out force and wear resistance capability of the thread when installed in softer materials - Easily replaced in the event of a stripped thread, cross-threaded, or worn threads - Easily installed using common Tooling	- Threaded fastener installation mounting hole may weaken the part as material is removed in a narrow cross-section - Incorrectly installed thread inserts can work out of their base material mounting holes

Welding Thread Repair Method

Illustration 37	g03889667
Steps to repair damaged threaded holes.

1. Machine threaded holes slightly larger than existing thread diameter.

2. Remove debris, oil, and water from the hole.

   Note: Any grease or contaminants trapped in the original hole can cause hard spots to develop in the weld material.

3. Apply a succession of welds starting at the lowest point of the hole until reaching top of the hole. De-scale between each pass, If multiple passes are needed.

4. After the welding process is complete, remove the excess weld material by either milling or grinding so that it is flush with the surrounding surface.

5. Drill and tap holes as per specifications.

6. Reinspect threaded holes.

Replacement Thread Inserts Method

Reference: SEHS8792 Special Instruction, "Using Caterpillar Replacement Thread Inserts" for information and procedures for Caterpillar replacement thread inserts. master kits, repair kits, and refill kits.

This salvage procedure consists of enlarging damaged threaded holes, tapping the hole with an oversize tap and installing a threaded insert.

Some applications may not have enough material in the hole boss to install an insert.

Replacement of damaged threads.

Machine Shop Practices

Note: The contents of this section are summaries of more detailed information. They are intended to supplement, not replace, the knowledge and skills possessed by experienced machinists.

Several aspects can affect the quality of machining operations used for parts salvage, and sometimes make the difference between success and failure. The most easily controlled aspects are cutter and work piece speed and feed rates, depth of cut, type, geometry, and condition of cutting tool. Machine tool rigidity, available horsepower, and the correct choice and maintenance of the cutting fluid are less obvious and not as easy for the machinist to control.

“Quality” of the machining operations can be described both in terms of visually observed “Surface Texture” and “Subsurface Material Alterations”.

Surface Texture Inspection

Surface texture refers to the roughness, waviness, lay, and flaws for a given surface. Surface texture can and will impact the interrelationship of components and therefore must have controls. In some applications too smooth can be as problematic as too rough. This holds true for gasket and seals. Surface texture can be measured with a profilometer.

Surface texture can have an impact in a gaskets ability to perform in the short term and over the long haul.

Aggressive surfaces can shear gasket materials, wear down more quickly and ultimately leak. This is often observed as fretting or false brinelling when evaluating head gaskets failures. -

Surfaces that are too smooth can allow gaskets to move excessively or flow which can lead to failure. -

No universal values for finished surfaces for these characteristics are given in this guideline because of the different application requirements. The following definitions will help you understand the relationship of surface texture and the aspects contributing to the texture.

Illustration 38	g06201117
Example of surface characteristics Depicts what a typical surface would appear like in a microscopic view.

Illustration 39	g06201162
Example of separation of roughness and waviness profiles from the total profile. Shows how a tracing of such a surface can be divided into the components of waviness, roughness, and total profile.

Definitions of Terms:

Surface - The boundary that separates an object from another object, substance, or space.

Surface Texture - The repetitive or random deviations from the nominal surface, which form the three-dimensional topography of the surface. Surface texture includes roughness, waviness, and lay. Refer to Illustrations 38 and 42.

Centerline - The graphical centerline is the line about which roughness is measured and is a line parallel to the general direction of the profile within the limits of sampling length, such that the sums of the areas contained between the graphical centerline and the parts of the profile, peaks, and valleys which lie on either side of it are equal.

Profile - The contour of the surface in a plane perpendicular to the surface (normal section), unless another angle is specified.

Peak - An outwardly directed (from the part material toward the surrounding medium) excursion of the assessment profile point above the profile centerline and between two crossings of the profile centerline.

Valley - An inward directed (into the part material) excursion of the profile below the profile centerline and between two crossings of the profile centerline.

Roughness - The finer irregularities of the surface texture, usually including those irregularities which result from the inherent action of the production process. Roughness includes all irregularities whose spacing is greater than the minimum roughness wavelength Ls and less than the roughness cutoff or Lc. The roughness cutoff is also known as the roughness sampling length. These are considered to include traverse feed marks and other irregularities within the limits of the roughness cutoff. Roughness is considered to be superimposed on a “wavy” surface.

Illustration 40	g06203065

Roughness Average (Ra) - The arithmetic average height of roughness irregularities measured from the centerline within the sampling length (L). Roughness Average is also known as Arithmetical Average (AA) and Centerline Average (CLA). Older instruments calibrated to display “RMS” values will give values 11% higher than Roughness Average (Ra). Ra is one of the most commonly used surface roughness measures. It gives a good general description of the height variations in the surface. Ra can leave much to be desired when trying to determine if a surface is smooth or aggressive. This can be undesirable when considering bearing surfaces and piston ring surfaces.

Maximum Roughness Depth (Rmax) - The largest of the 5 maximum peak-to-valley roughness depths in 5 successive sampling lengths.

Roughness Average Spacing (Rsm) - The average spacing of the sampling length.

Illustration 41	g06206638

Average Roughness Depth (Rz) - The average of 5 maximum peak-to-valley roughness depths in 5 successive sampling lengths. This provides a more accurate depiction of the surface as it does not just average in outliers of a profile.

Waviness - The more widely spaced component of surface texture. Waviness results from such factors as machine or part deflections, vibration, chatter, heat treatment, warping strains, or other factors. Waviness includes all irregularities whose spacing is greater than the roughness cut off Lc and less than the waviness cut off Lf. The waviness cutoff is equal to the waviness sampling length which usually works best to be equal to the roughness measurement length (roughness assessment length). Waviness is only able to be measured using a skidless surface texture instrument.

R Profile - The roughness profile, used to determine R parameter values.

W Profile - The waviness profile, used to determine W parameter values.

P Profile - The primary profile, which is the combination of the R and W Profiles (only form error removed), which is used to determine P parameter values.

Ls - Lower bound of wavelengths that are considered part of the roughness profile, specified in µm.

Lc - The roughness cutoff which is the boundary between surface features that are considered part of the roughness profile and surface features that are considered part of the waviness profile, specified in mm. “Lc” can also be used to indicate the roughness sampling length.

Lf - The upper bound of wavelengths that are considered part of the waviness profile, specified in mm. “Lf” can also be used to indicate the waviness cutoff or sampling length.

Rough Assessment Length (Ln) - Several sampling lengths Lc or Lf defined here are combined to comprise the assessment length. The roughness sampling length is the length over which roughness parameters are evaluated. The roughness assessment length, if possible, shall include a minimum of five or more roughness cutoff or sampling lengths, but may be longer as necessary.

Stylus - The contacting interface of the measurement instrument to the surface being measured in contact measurements (also called stylus or trace measurements). Typical styli are 2, 5, and 10 µm in radius and have a conical shape with 60 or 90 degree included angle. Pyramidal (i.e., chisel) shapes are less typical, but sometimes specified. The stylus, typically fitted with a diamond that makes contact with the surface being analyzed. The up and down travel of the stylus is measured and a given roughness output will be displayed.

Lay - The direction or description of the predominant surface pattern, ordinarily determined by the production method. Lay is the direction of the predominate pattern of the surface texture. It is designated by geometric symbols or letters which are located to the right of the long leg of the surface texture symbol. Specific processing controls shall also be added as shown in Illustration 43. Conformance shall be determined by visual inspection.

Flaws - Unintentional surface discontinuities which occur at one place or at relatively. Flaws are not necessarily defects, but do include such drag, gouges, and ridges defects as cracks, blow holes, inclusions, checks, tool drag marks, gouges, and ridges. Flaws are not intended to be controlled by surface roughness measurements.

Surface Texture Testing

Note: Both the American National Standard ANSI B46.1 and Y14.36 and International Standard ISO 1302, 3274, 4287, 4288, 5436, 8785,11562, and 13565.describe and standardize acceptable measuring instrumentation for surface texture.

Illustration 42	g06087608

One-Sided Lower Hard Tolerances - When a single roughness specification is followed by the designation MINIMUM, as in Illustration 42, it is the minimum allowable value on that surface. The surface is considered acceptable if no measured values of that surface are less than the specified value in accordance with ISO 4288.

One-Sided Upper Hard Tolerances - When a single roughness specification is followed by the designation Maximum, as in Illustration 42, it is the maximum allowable value on that surface. The surface is considered acceptable if no measured values of that surface are less than the specified value in accordance with ISO 4288.

Method To Measure And Accept Or Reject The Work Piece Under The 16% Rule - Where the indicated parameter symbol does not contain the suffix MIN or MAX initially, the surface will be accepted and the test procedure stopped if:

• The first measured value does not exceed 70% of the value indicated on the drawing.

• The first value exceeds 70%, measure two more places, and these first three measured values do not exceed the specified value.

• One of these first three measured values is out of tolerance, then measure three more places, and if not more than one of these first six measured values exceeds the specified value.

• Two of the six values are out of tolerance, then measure six more places, and if not more than two of these first twelve measured values exceed the specified value.

When using this method for assessing whether the surface passes the 16% statistical tolerance limit, the value to be assigned the surface parameter being measured is the average of all the final numbers of traces required to accept the surface. For example, if three traces had to be taken, and all three values are within the limits as in the second bullet above, then the value of the parameter to be assigned is the average of the three values that resulted from the three traces.

Note: It is not acceptable practice to take multiple traces and ignore results that tend toward rejecting the surface until one or more traces are taken that tend to comply toward acceptance. For example, it is not acceptable practice to keep taking traces until one reaches a trace with the prescribed parameter results below 70% of the tolerance. The method described above is the statistically correct sampling method. Therefore in carrying out the measurement process, if any one of the conditions is not met, the surface is out of specification. For example if in the first measurements, two or more traces are taken that are just below or above the finish parameter tolerance (and thus not below 70% of the tolerance) then the surface finish requirement has not been met and the work piece is not compliant.

Note: If instructions are to assess a Part Number work piece surface by taking multiple surface traces, possibly in certain locations, then set of traces can be carried out by following the above set of rules for the number of traces prescribed. For example, engine liner bore finishes are instructed to be assessed by taking twelve traces in the pattern of three levels with four traces at each level. Then by the fourth bullet above up to two of these traces can have parameter results outside of the tolerance and the set of twelve traces can still make the bore acceptable. Then if the bore is acceptable in this way, the parameter results to be assigned for that bore is the averages of the twelve parameter results from the twelve traces.

Note: Alternatively, if the number of traces specified is for example two or four or five traces, then if one of these traces violates the above conditions, then additional traces can be added to the sampling of the finish, in the area of the questioned trace, until the total number traces such as three or six or twelve is taken as in the above sequence to see if the surface is still compliant with the above process. For example, if two are specified and one of the two traces is above 70% of the tolerance, then a third trace can be taken to show that the surface complies with the second bullet above. Then if the second bullet condition is met, the parameter result(s) for the surface for this example is not the average of two parameter results, but the average of the three.

Non-Periodic or Random Surfaces

Table 6

Ground, Honed, Blasted, Edm'd, Etc. Surfaces
AVERAGE SURFACE ROUGHNESS Ra	AVERAGE PEAK TO VALLEY HEIGHT Rz	STYLUS TIP RADIUS	Ls	Lc	Ln
µm	µm	µm	µm	mm	mm
Ra ≤ 0.02	Rz ≤ 0.1	2	2.5	0.08	0.4
0.02 < Ra ≤ 0.1	0.1 < Rz ≤ 0.5	2	2.5	0.25	1.25
0.1 < Ra ≤ 2	0.5 < Rz ≤ 10	2	2.5	0.8	4
2 < Ra ≤ 10	10 < Rz ≤ 50	5	8	2.5	12.5
10 < Ra ≤ 80	50 < Rz ≤ 300	10	25	8	40

Periodic Surfaces

Table 7

Turned, Bored, Milled, Etc. Surfaces
AVERAGE FEATURE SPACING Rsm	STYLUS TIP RADIUS	Ls	Lc	Ln
mm	µm	µm	mm	mm
Rsm ≤ 0.03	2	2.5	0.08	0.4
0.03 < Rsm ≤ 0.1	2	2.5	0.25	1.25
0.1 < Rsm ≤ 0.3	2	2.5	0.8	4
0.3 < Rsm ≤ 1	5	8	2.5	12.5
1 < Rsm ≤ 3	10	25	8	40

Stylus - The stylus used to measure the surface shall meet the requirements of ANSI B46.1 as in Tables 6 and 7. The direction of stylus travel shall be in the direction which gives the maximum reading.

Chisel Shaped Stylus - A chisel shaped stylus shall be used when chisel stylus is specified in the drawing callout as shown in Illustration 42. The maximum width of the chisel stylus shall be 1.60 mm (0.063 inch) and the tip radius shall be 0.0125 mm (0.00050 inch), or the appropriate radius as listed in Tables 6 and 7

Skidless Contact Stylus Instruments - Skidless contact stylus instruments are surface texture measuring machines having only the stylus itself extending out of the probe body which then contacts the surface. They have a precision straight motion axis integrated in the probe head or probe drive unit that provides the reference straight motion that the surface location at any point in the surface trace is measured against.

Calibration And Checking Of The Measuring Instrument - All surface texture measuring instruments require frequent calibrations and checks to provide reliable results. Calibration specimens are provided by the instrument maker and are generally in the form of step groove masters, circular groove masters. or sinusoidal master patches.

When To Calibrate - A calibration or calibration check shall be carried out at the beginning of a shift, or whenever the instrument is “bumped” or otherwise disturbed, whenever there is a large change in the instrument’s environment, at the beginning of measuring a significant number of work pieces that need to have their results compared to each other, and/or whenever the stylus is changed. A calibration check can be typically carried out by an operator, where a full calibration may require support from a quality engineer or equivalent.

Illustration 43	g06202816

Surface Lay - Lay is the direction of the predominate pattern of the surface texture. It is designated by geometric symbols or letters which are located to the right of the long leg of the surface texture symbol. Specific processing controls shall also be added as shown in Illustration 43. Conformance shall be determined by visual inspection.

Hardness Checks

Hardness should be measured using a suitable Leeb type hardness tester. Persons should be qualified or properly trained in how to use the hardness tester to ensure good results.

Note: A minimum hardness reading of 45 Rockwell "C" (RC) or 430 Brinell (10 mm steel ball) is required in the rope grooves of the drum.

Directions for using a Detroit Hardness Tester

Follow Steps 1 through 8 for using a Detroit Leeb Hardness Tester:

1. Locate area to be tested.

2. Use a non-metallic synthetic buffing wheel to clean bottom of grooves in area to be hardness tested.

3. Turn tester upside down allowing the ball to seat in the cap.
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   Illustration 44	g06085908
   Typical example (E) Leeb type hardness tester.

4. Turn tester right side up and place on area that has been cleaned. Refer to Step 2.

5. Hold tester vertically and steady.

6. Slowly depress trigger, do not strike or you will get an inaccurate reading.

7. Read the top of the ball at the highest point of the balls bounce.

8. Repeat Steps 3 through 7 for each test location three times to obtain an accurate reading.

Subsurface Material Alterations

All machining operations performed on a part will cause subsurface alterations of the material. The alterations, usually occurring within the first 0.38 mm (0.015 inch), include such defects as cracks, hardness changes, laps, metallurgical transformations, pits, residual stresses, folds, and seams etc.

Although the alterations may not cause problems during rough machining operations, in low stress applications, or with parts having wide surface feature tolerances, they could have serious consequences if they occur on highly loaded, closely tolerance parts.

Chip Cutting Guidelines

1. Keep cutting edges sharp. Dull tools promote plastic flow of the work surface with resulting tears, laps, and roughness. Those surface defects can produce places for stresses to concentrate and may result in fatigue failures. For finish cuts, the wear land on the cutter flank should not exceed 0.13 mm to 0.20 mm (0.005 inch to 0.008 inch), which is the point the wear becomes visible.

   The extra heat generated by dull cutting edges will also cause changes in metallurgy and surface burns. The metallurgy changes can result in either excessively hard or soft surfaces. Remove surface burns, which can be as deep as 0.25 mm (0.010 inch), to prevent the possibility of fatigue cracking.

2. Keep drill cutting edges sharp with maximum wear land of 0.13 mm to 0.20 mm (0.005 inch to 0.008 inch) to minimize tears, laps, and changes in metallurgy, especially in highly loaded parts.

   Avoid hand-fed drilling operations to prevent hole damage caused by feed dwell. Also, use fixtures and/ or bushings to prevent damage. Provide chip clearance between the work piece and drill bushing for holes deeper than three times the diameter.

3. Ream holes of 7.9 mm (0.31 inch) in diameter and larger in two steps. Allow a minimum diametrical stock removal of 1.2 mm (0.05 inch). Allow at least 0.4 mm (0.02 inch) stock removal in smaller holes.

   Deburr and chamfer any drilled and reamed holes to avoid potential fatigue failures. Remove at least 0.25 mm (0.010 inch) during the chamfering.

4. Inspect reamers after using. At the first sign of wear or chipping, replace the reamers.

5. Honing with a multi-stone head produces the least change of work piece surface of any conventional operation of metal finishing.

6. Boring with new sharp cutting tools can, usually produce acceptable size accuracy and surface texture. Tool wear land must not exceed 0.13 mm (0.005 inch).

Abrasive Processes

Machining (grinding) processes that are abrasive may produce the greatest loss in fatigue strength of the common processes.

• Low stress grinding techniques reduce distortion and surface damage, and are recommended for final grinding of heat treated or high strength steels. Results are accomplished by using softer grade grinding wheels, dressing coarse wheels frequently, using lower feeds and speeds, and using lubricating type cutting fluids. Low stress grinding should be used for the final 0.25 mm (0.010 inch) of stock removal.

• “Conventional” grinding is not recommended to finish grinding heat-treated or high strength steels. The heat-affected zone can be much deeper than surface color indicates. High stresses created in conventional grinding can cause the work piece to crack days after the grinding is completed, or prematurely in service.

• The hand grinding process creates a lack of control, which can produce unpredictable surface integrity and should be avoided if possible.

• Honing generates a true cylindrical form regarding roundness and straightness. Honing also generates a final dimensional accuracy with low tolerances and provides high-quality surface texture with the least amount of taper.

Cutter and Work Piece Feeds And Speeds: Depth Of Cut

Feeds, speeds, and depths of cut depend upon many variables, and what is required for the workpiece. At best, any suggested combination of feeds, speeds, and depth of cut is a starting point. Several aspects would require adjustments to those settings are: compensating for variations in machine tool horsepower, rigidity and condition, cutting edge type and condition, and operator skill and attitude. Also, work piece material, the amount of material removed and the numbers of cuts to remove the material, and the desired surface texture and surface integrity will affect the settings used.

Because of the many variables involved in selecting a feed/ speed/ depth of cut combination, and the machinist guides that are currently available, no specific recommendations are included in this guideline.

Crack Detection Methods

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NOTICE
Regardless of which crack detection method is used, it is important that the instructions furnished with the detection equipment are followed closely when checking any component. Failure to do so may cause inaccurate results or may cause injury to the operator and/or surroundings.

Crack detection methods or Non-Destructive Testing (NDT) are utilized for examining components for cracks without damaging the component. Visual inspection (VT), Liquid Penetrant Testing (PT), Magnetic Particle Inspection (MT), Ultrasonic Testing (UT), Radiographic Testing (RT) and Eddy-Current Testing (ET) are recommended methods. There may be more than one acceptable crack detection method for the inspection of a given part, though the liquid penetrant is the most versatile. For example, the liquid penetrant method can be used when inspecting smooth machined components such as shafts, gear teeth, and splines, but using the Wet Magnetic Particle Inspection is more accurate. Refer to Table 8 for advantages and disadvantages and Table 9 for standards and requirements for these NDT methods.

Table 8

Crack Inspection Method Advantages vs. Disadvantages
Inspection Method	Advantages	Disadvantages
Visual Surface Inspection (VT)	- Least expensive - Detects most damaging defects - Immediate results - Minimum part preparation	- Limited to surface-only defects - Requires inspectors to have broad knowledge of welding and fabrication in addition to non-destructive testing
Liquid Penetrant (PT)	- Inexpensive - Minimal training - Portable - Works on nonmagnetic material	- Least sensitive - Detects surface cracks only - Rough or porous surfaces interfere with test
Dry Magnetic Particle (MT)	- Portable - Fast/Immediate Results - Detects surface and subsurface discontinuities	- Works on magnetic material only - Less sensitive than Wet Magnetic Particle
Wet Magnetic Particle (MT)	- More sensitive than Liquid Penetrant - Detects subsurface as much as 0.13 mm (0.005 inch)	- Requires Power for Light - Works on magnetic parts only - Liquid composition and agitation must be monitored
Ultrasonic Testing (UT)	- Most sensitive - Detects deep material defects - Immediate results - Wide range of materials and thickness can be inspected	- Most expensive - Requires operator training and certification - Surface must be accessible to probe
Eddy-Current Testing (ET)	- Surface and near surface flaws detectable -Moderate speed/Immediate results -Sensitive too small discontinuities	- Difficult to interpret - Only for metals -Rough surfaces interfere with test - Surface must be accessible to probe
Radiographic Testing (RT)	-Detects surface and internal flaws - Minimum part preparation - Can inspect hidden areas	- Not for porous materials - Radiation protection needed - Defect able to be detected is limited to 2% of thickness

Table 9

Applicable Crack Detection Standards
Inspection Method	Standard	Acceptance Criteria	Required Personnel Qualifications
Visual Surface Inspection (VT)	EN-ISO 5817 AWS D1.1	EN-ISO 5817 - Level B AWS D1.1 - Table 6.1	EN-ISO 9712 - Level 2 ANSI-ASNT SNT-TC-1A Level 2
Liquid Penetrant Testing (PT)	EN-ISO 3452 ASTM E165	EN-ISO 23277 AWS - D1.1	EN-ISO 9712 - Level 2 ANSI-ASNT SNT-TC-1A Level 2
Magnetic Particle Testing (MT)	EN-ISO 17638 ASTM E709	EN-ISO 23278 - Level 1 AWS D1.1 - Table 6.1	EN-ISO 9712 - Level 2 ANSI-ASNT SNT-TC-1A Level 2
Ultrasonic Testing (UT)	EN-ISO 17640 - Level B AWS D1.1	EN-ISO 11666 Technique 2 - Level 2 AWS D1.1 - Class A - Table 6.3	EN-ISO 9712 - Level 2 ANSI-ASNT SNT-TC-1A Level 2
Eddy-Current Testing (ET)	EN-ISO 15549 ASTM E426	EN-ISO 20807	EN-ISO 9712 - Level 2 ANSI-ASNT SNT-TC-1A Level 2
Radiographic Testing (RT)	EN-ISO 5579 ASTM E94	EN-ISO 10657-1	EN-ISO 9712 - Level 2 ANSI-ASNT SNT-TC-1A Level 2

Visual Surface Inspection (VT)

Illustration 45	g06085008
Example of Visual Inspection Tools (A) Flashlight or adequate light source (B) Magnifying eye loupe (C) Tape measure or other measuring device (D) Inspection mirror (E) Weld size inspection gauges

Components and welds that are to be inspected using PT, MT, or UT shall first be subject to Visual Surface Inspection (VT). Visual Inspection is often the most cost-effective inspection method and requires little equipment as seen in Illustration 45. It is suggested that at a minimum personnel performing Visual Inspection are either trained to a company standard or have sufficient experience and knowledge regarding the components being inspected. It is also suggested that personnel performing visual inspections take some type of eyesight test regularly.

Liquid Penetrant Testing (PT)

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Personal injury can result from improper handling of chemicals. Make sure you use all the necessary protective equipment required to do the job. Make sure that you read and understand all directions and hazards described on the labels and material safety data sheet of any chemical that is used. Observe all safety precautions recommended by the chemical manufacturer for handling, storage, and disposal of chemicals.

Materials and Equipment Required

Refer to Tooling and Equipment Table 3 for part numbers.

• Cleaner: Removes dirt before dye application and dissolves the penetrant making possible to wipe the surface clean.

• Penetrant: This solution is highly visible, and will seep into openings at the surface of a part with capillary action.

• Developer: Provides a blotting action, bringing the penetrant out of the discontinuities and providing a contrasting background to increase the visibility of the penetrant indications.

• Wire Brush: Removes dirt and paint.

• Cloth or Wipes: Use with cleaner and for other miscellaneous uses.

Procedure

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Illustration 46	g06107074
Typical example of pre-cleaning area.

1. Preclean inspection area. Spray on cleaner / remover to loosen any scale, dirt, or any oil. Wipe the area to inspect with a solvent dampened cloth to remove remaining dirt and allow the area to dry. If there is visible crack remove paint using paint remover or wire brush.
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   Illustration 47	g06107081
   Typical example of applying penetrant.

2. Apply penetrant by spraying to the entire area to be examined. Allow 10 to 15 minutes for penetrant to soak. After the penetrant has been allowed to soak, remove the excess penetrant with clean, dry wipe.
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   Illustration 48	g06107088
   Typical example of removing excess penetrant oil.

3. The last traces of penetrant should be removed with the cleaner solvent dampened cloth or wipe. Allow the area to dry thoroughly.
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   Illustration 49	g06107094
   Typical example of applying developer.

4. Before using Developer, ensure that it is mixed thoroughly by shaking can. Holding can approximately 203.20 - 304.80 mm (8.00 - 12.00 inch) away from part, apply an even, thin layer of developer over the area being inspected. A few thin layers are a better application method than one thick layer.
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   Illustration 50	g06084042
   Typical example of cracks found during a liquid penetrant testing.

5. Allow the developer to dry completely for 10–15 minutes before inspecting for cracks. Defects will show as red lines in white developer background, refer to Illustration 50. Clean the area of application of the developer with solvent cleaner.

Dry Magnetic Particle Testing (MT)

Materials and Equipment Required

Refer to Tooling and Equipment Table 3 for part numbers.

Illustration 51	g06085930
(A) Indications shown by magnetic particle testing. (B) Typical electromagnetic yoke. (C) Dry powder bulb.

1. Dry magnetic powder shall be of high permeability and low retentively and of suitable sizes and shapes to produce magnetic particle indications. The powder shall be of a color that will provide adequate contrast with the background of the surface being inspected.

2. Dry magnetic particles shall be stored in suitable containers to resist contamination such as moisture, grease, oil, non-magnetic particles such as sand, and excessive heat. Contaminants will manifest in the form of particle color change and particle agglomeration. The degree of contamination will determine further use of the powder.

3. Dry magnetic powder shall be tested in accordance with ASTM E709 Section 18 (Evaluation of System Performance/Sensitivity) when not performing.

4. Equipment should include a "U" shaped electromagnetic yoke made from highly permeable magnetic material, which has a coil wound around the yoke. This coil carries a magnetizing current to impose a localized longitudinal magnetic field into the part. The magnetizing force of the yoke is related to the electromagnetic strength and can be tested by determining the lifting power of a steel plate. The yoke shall have a lifting force of at least 4.5 kg (10 lbs).

5. Check dry powder blower routinely to ensure that the spray is a light, uniform, dust-like coating of the dry magnetic particles. Blower should also have sufficient force to remove excess particles without disturbing those particles that are evidence of indications.

6. All equipment shall be inspected at a minimum of once a year or when accuracy is questionable.

Procedure

1. Ensure surface to be inspected is dry and free from oil, grease, sand, loose rust, mil scale, paint, and other contaminants.

2. Apply the magnetic field using the yoke against the faces and inside diameter of each bore.

3. Simultaneously apply the dry powder using the dry powder blower.

4. Remove excess powder by lightly blowing away the dry particles.

5. Continue around the entire circumference of each bore. Position the yoke twice in each area at 1.57 rad (90°) to ensure that multiple directions of the magnetic field are created.

6. Observe particles and note if any clusters of particles appear revealing an indication.

7. Record the size and shape of any discontinuities or indications found.

Wet Magnetic Particle Testing (MT)

Materials and Equipment

Refer to Tooling and Equipment Table 3 for part numbers.

Illustration 52	g06085937
(A) Indications shown by magnetic particle testing. (B) Typical electromagnetic yoke. (D) UV Lamp used in wet magnetic particle inspection process.

Illustration 53	g06003178
Pear Shaped Centrifuge Tube

1. Wet magnetic particles are fluorescent and are suspended in a vehicle in a given concentration that will allow application to the test surface by spraying.

2. Concentration:

   1. The concentration of the suspended magnetic particles shall be as specified by the manufacturer and be checked by settling volume measurements.

   2. Concentrations are determined by measuring the settling volume by using an ASTM pear shaped centrifuge tube with a 1 mL (0.034 oz) stem with 0.05 mL (0.0017 oz) 1.0 mL (0.034 oz) divisions, refer to Illustration 53. Before sampling, the suspension shall be thoroughly mixed to assure suspension of all particles, which could have settled. A 100 mL (3.40 oz) sample of the suspension shall be taken and allowed to settle for 30 minutes. The settling volume should be between 0.1 mL (0.0034 oz) and 0.25 mL (0.0085 oz) in a 100 mL (3.40 oz) sample.

   3. Wet magnetic particles may be suspended in a low viscosity oil or conditioned water.

   4. The oil shall have the following characteristics:

      • Low viscosity not to exceed 50 mSt (5.0 cSt) at any temperature at which the vehicle is to be used.

      • Low inherent fluorescence and be non-reactive.

   5. The conditioning agents used in the conditioned water shall have the following characteristics:

      • Impart good wetting characteristics and good dispersion.

      • Minimize foaming and be non-corrosive.

      • Low viscosity shall not exceed a maximum viscosity of 50 mSt (5.0 cSt) at 38° C (100° F).

      • Non-fluorescent, non-reactive, and odorless.

      • Alkalinity shall not exceed a pH of 10.5.

3. Equipment should include a "U" shaped electromagnetic yoke made from highly permeable magnetic material, which has a coil wound around the yoke. This coil carries a magnetizing current to impose a localized longitudinal magnetic field into the part. The magnetizing force of the yoke is related to the electromagnetic strength and can be tested by determining the lifting power of a steel plate. The yoke shall have a lifting force of at least 4.5 kg (10 lbs).

Procedure

1. Ensure surface to be inspected is dry and free from oil, grease, sand, loose rust, mil scale, paint, and any other contaminants.

2. Apply the magnetic field using the yoke against the surface in the area to be inspected.
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   Illustration 54	g03536210

3. For case hardened and ground surfaces:

   • Due to the sensitivity required to locate the grinding cracks, inspection of case hardened and ground surfaces require that the yoke is applied so that the magnetic field is 1.57 rad (90°) to the expected direction of the indications. Also, due to the increased sensitivity resulting when the yoke is energized, the yoke is not moved until the evaluation is completed in the first direction. An AC yoke shall be used. See Illustration 54 for an example of yoke placement.

4. Visually inspect for indications of discontinuities using the proper illumination.

5. Record the size and shape of any discontinuities found.

Ultrasonic Testing (UT)

Note: Crack depth cannot be accurately determined by UT, only full depth cracking can be consistently determined. For cracks that are not full depth, an indication of a partial depth cracks can be detected by an experienced technician.

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NOTICE
All personnel involved in ultrasonic testing shall be qualified to Level 2 in accordance to standards stated in Table 9.

Refer to Tooling and Equipment Table 3 for part numbers.

1. Ultrasonic Testing (UT) is a method of Non-Destructive Testing (NDT) using short ultrasonic pulse waves (with frequencies from 0.1-15 MHz up to 50 MHz) to detect the thickness of the object. Ultrasonic testing consists of an ultrasound transducer connected to a diagnostic machine and passed over the object being inspected.

2. There are two methods of receiving the ultrasound waveform from the transducer: reflection and attenuation.

   1. Reflection - Ultrasonic pulses exit the transducer and travel throughout the thickness of the material. When the sound waves propagate into an object being tested, the waves return to the transducer when a discontinuity is discovered along the sonic path. These waves continue and reflect form the backsurface of the material to project the thickness of the material.

   2. Attenuation - A transmitter sends ultrasound through one surface, and a separate receiver detects the amount that has reached it on another surface after traveling through the medium. Any discontinuities or other conditions within the medium will reduce the amount of sound transmitted, revealing the presence of the imperfections.

Eddy-Current Testing (ET)

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NOTICE
All personnel involved in Eddy-Current Testing shall be qualified to Level 2 in accordance to standards stated in Table 9.

Illustration 55	g06090873
Eddy-Current Testing

Eddy-Current Testing (ET) is a Non-Destructive Testing (NDT) method in which eddy-current flow is induced in the test object. Changes in the flow caused by variations in the specimen are reflected in to a nearby coil or coils for subsequent analysis by suitable instrumentation and techniques. Major applications of eddy-current testing are surface inspection and tubing inspections.

Radiographic Testing (RT)

Note: CAUTION: This process is dangerous. Only qualified personnel and test equipment should be appointed to perform this type of testing.

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NOTICE
All personnel involved in radiographic testing shall be qualified to Level 2 in accordance to standards stated in Table 9.

Illustration 56	g06090892
Radiographic Testing

Radiographic Testing (RT) is a Non-Destructive Testing (NDT) method in which short wavelength of electromagnetic radiation is used to penetrate materials to find hidden discontinuities such as cracks. In radiographic testing, the test object is placed between the radiation source and the film, or x-ray detector. The electromagnetic radiation will penetrate the thickness of the test object and, when all the way through, will project onto the film any indications that have been in the path of the radiation waves.