Suggestions on the Best way to Repair

jpitz31 · Jan 8, 2020

Best way to Repair Stripped Acme lead screw

Hi All, Just removed the acme lead screw on my mill for cleaning. Turns out one side was cross threaded. I had to twist the end thrust nut off of the shaft.
See attached images:

I was thinking that the best way to repair is to turn and thread the next size down and manufacture another thrust nut with the smaller thread size. But I am concerned
about how much to thread while keeping the more inward shaft diameter the same as the original so I can still tighten the thrust nut.

Any suggestions would be greatly appreciated.

Joe

HuFlungDung · Jan 9, 2020

You can get fancy and make the new nut with an extended boss sticking out, bored for a clearance fit over the diameter of the main shaft. This will prevent the nut from hitting against the shoulder you plan to create when you cut the new threads.

Less fancy: just add a spacing washer.

I hate seeing setscrew locks on top of threads, which is probably why the threads galled up and seized when you tried to remove the nut. I prefer a double nut which you lock against itself. Even loctite is better than a setscrew, but you might have to remember to heat the nut for removal later on (after you've forgotten about the loctite).

Scottl · Jan 9, 2020

Suggest you modify your title to be more descriptive or the thread may get locked.

DDoug · Jan 9, 2020

Scottl said:
Suggest you modify your title to be more descriptive or the thread may get locked.

More importantly, simply continue on with the existing thread the OP has on this mill.

No need to re-invent the wheel here.

eKretz · Jan 9, 2020

HuFlungDung said:
I hate seeing setscrew locks on top of threads, which is probably why the threads galled up and seized when you tried to remove the nut. I prefer a double nut which you lock against itself. Even loctite is better than a setscrew, but you might have to remember to heat the nut for removal later on (after you've forgotten about the loctite).

I don't have a problem with a setscrew against external threads if it's done right. That means a copper, brass or nylon insert bearing against the external thread, and the insert threaded in place so it mates well with the thread and doesn't damage it. Although I definitely concede that this is finicky compared to the other possibilities.

jpitz31 · Jan 9, 2020

Thanks All, I changed the title of the post, But I do not believe I have permission to move the thread, do not see an option in advanced options.

jpitz31 · Jan 9, 2020

Thanks, I love your user name, My wife is Chinese, I will be sure to tell her this one.

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Suggestions on the Best way to Repair

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