Posted by Vaughn [172.68.34.31] on Thursday, April 04, 2019 at 19:31:43 :
This analysis covers the idler gear and shaft for PTO 12525 on the Heavy-Duty Spur Gear #38711. Condition – gear causes vibration and rattles when coasting downhill, so I am going to have a new shaft made and hardened insert installed in gear to bring components back in specs. Military part manufacturers on contract with the Government to supply parts for trucks still in service use the one of the following steels to make the reverse gear shaft which I am going to apply to the idler shaft as well – 1015, 1016, 1018, 1019 or 1020. In looking at the makeup of these steels, 1015 seems to be the best for hardness/wear, using a hardness rating of 58.0 Rockwell C minimum overall and 63.0 Rockwell C maximum overall. I’m going to use a clearance of 0.001 between gear, bearing, and shaft. The combination of my units is presently 0.0115 so I am way out. The gear and shaft are the two parts I have never been able to find NOS. I take any advice you have on what I plan to present to the machine shop. Thanks!
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