COVER 3774952 - Caterpillar

Illustration 103 g03307317First rough center the gear on the lathe. If desired, the use of a cone fitting on the tail stock can help with this process.
Illustration 104 g03306717
Hardened gage pins clamped in place under the clamping teeth.
Illustration 105 g03307436
Magnetic gage pins in place around the gears.
To accomplish locating the pitch line datum, use a matched set of hardened gage pins held under the clamping teeth of the cutting machine. Refer to Illustration 104.An alternative for using clamped gage pins is to use a matched set of magnetic gage pins next to the jaws to attain a pitch line. Refer to Illustration 105.The diameter of the gage pins used will vary with different gear sizes. Refer to Table 33 for gage pin and gear matching information.
Illustration 106 g03307017After securing the gear and the correct gage pins, the gear must be aligned for cutting. Take readings on the outer side of the gage pins with a properly affixed dial indicator, refer to Illustration 106. This measurement will ensure that the gear is centered in the machine in relation to the pitch line datum of the gear teeth.Note: If using magnetic gage pins, take care the magnetic draw of the gage pins does not cause an inaccurate reading of the dial indicator.Continue to adjust the locating jaws until the reading of the dial indicator is within the tolerance listed in "Max Pitch TIR" within Table 33.
Illustration 107 g03307542Check the face perpendicularly with the dial indicator, refer to Table 33 for the minimum specifications.Adjust the surface of the gear until within "Maximum Gear Perpendicular Runout" specification found within Table 33. The gear is now centered by the pitch line and perpendicular to the cutting machine. Recheck the gage pins to ensure that the face adjustment has not compromised the pitch adjustment.Machining the Gear Bearing Sleeve
Note: If the stub shaft is to be reused, then check the stub shaft prior to machining the bearing sleeve.The best results for machining the gear bearing sleeve is obtained by using two passes. The first pass will machine the bearing sleeve to within 0.051 mm (0.002 inch) or less. The second and final pass will machine to final size and final surface texture. When done correctly, this two-step procedure will leave an acceptable finish requiring no further attention.Note: The feed and RPM rates for your individual cutting tool, machine, and gear will vary to achieve the best surface texture. Various cutting tools have been used with different RPM and feed rates to achieve similar results. For example, a Valenite cutter using a TNMP432 insert used at 1800 RPM and a 0.04572 mm (0.0018 inch) feed rate produced similar results as a CNMG432MP insert at 850 RPM and a 0.04064 mm (0.0016 inch) feed rate.Note: The required specifications for cutting aluminum bearing sleeves are in Section "Machining Aluminum Bearing Sleeves" below.
Illustration 108 g03784239Using high RPM and slow feed rate will produce the best finish results.Machining Aluminum Bearing Sleeves
Machining of the aluminum bearing sleeve requires cutting inserts particular to the properties of the metal.