what is the technique for a stripped thread in hardened material?, how to re-tap a pinion shaft threads / Tranny problems |
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what is the technique for a stripped thread in hardened material?, how to re-tap a pinion shaft threads / Tranny problems |
brant |
Oct 22 2020, 09:21 AM
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#1
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914 Wizard Group: Members Posts: 11,639 Joined: 30-December 02 From: Colorado Member No.: 47 Region Association: Rocky Mountains |
Ok...
so I had a big transmission failure this box was built by a friend, at a clinic I'm guessing the 30mm Bolt (for the speedo drive) was not torqued correctly? apparently it came loose the stack slid and drove the brass angle drive through the back of the tail cone the little button in the picture is the plug from the magnesium tail cone but as you can see the bolt threads were heavily damaged I have a replacement bolt with good threads but the threads inside the pinion shaft received some damage also I have the correct tap but the material of the pinion shaft is so hard, that I can't get the tap to start What is the technique to thread something hardened? I'm betting the process involved heat, and softening the metal then rehardening... which may not be a good idea with a pinion shaft so I may need to build a different transmission but if I could tap this thread, I'd be willing to give this box a shot. any metal experts out there.. or machinist know if this is possible? thanks in advance brant Attached thumbnail(s) |
brant |
Oct 26 2020, 03:28 PM
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#2
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914 Wizard Group: Members Posts: 11,639 Joined: 30-December 02 From: Colorado Member No.: 47 Region Association: Rocky Mountains |
Chris, Jeff, EVERYONE....
thank you again for all of the advice tips and help Update I followed Jeff's idea. I carefully measured the depth and used a dremel to remove 2 or so threads from the beginning that were mushroomed. and then.... I WAS ABLE TO GET MY TAP STARTED success... threads restored. bolt inserted ... blue lock tite used... torque achieved I'm going to pull the box from the chassis now and finish the rebuild. I've got the stack back together and ever thing looks visually good I even replaced 1st syncro while I was there. once I get the shell out, I'll wash it out better... replace both side shaft seals and the front main while I'm there.... planning on pulling tonight. Hopefully I'll save this box as all of the sliders and parts are really in decent shape (reflecting the few thousand miles put on it since Jeff (RIP) built it at a clinic thanks again EVERONE! Gint. Hopefully I can return your cores soon I washed up the one missing the shift console brant |
Superhawk996 |
Oct 28 2020, 05:42 AM
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#3
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914 Guru Group: Members Posts: 5,892 Joined: 25-August 18 From: Woods of N. Idaho Member No.: 22,428 Region Association: Galt's Gulch |
and then.... I WAS ABLE TO GET MY TAP STARTED success... threads restored. bolt inserted ... blue lock tite used... torque achieved I'm glad to be wrong -- Great news that you were able to save the shaft. And . . . I may have learned a new trick along the way. (IMG:style_emoticons/default/pray.gif) |
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