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Tool Caliper with broken screw

Tool
Is using a threading die out of the question?

No, it's a very reasonable way to do it. The problem with that option is that I'd have to go with standard SAE thread profile. If I have to do that, I might as well just get threaded bar and a nut from MC. Which I still might do. I'm not sure how much benefit there is in the Acme thread profile but it is not zero. To rebuild it to factory, an Acme thread is required. To do that, I'd have to single point. Albeit still with a slight thread pitch mismatch.
 
From the latest post to the H-M thread:

IMG_9012.jpeg
 
From the latest post to the H-M thread:

$122US. That's $200 Cdn. Not happening Charlie!

More and more I'm leaning toward just buying a piece of 2-56 threaded rod and a ball nut from McMaster-Carr. It's not a perfect original repair, but it is more than adequate for my needs.

Even that is not without issues. I'd still have to drill it for the pin.....
 
Cut your self a gear and then you don't need to modify the nut and then it is as original as it can be. Everyone knows it's not a real project unless it requires at least 1 other sub project first.:D
 
Cut your self a gear and then you don't need to modify the nut and then it is as original as it can be. Everyone knows it's not a real project unless it requires at least 1 other sub project first.:D

That's very true. But it's more than a gear (or two). It's also a micro travelling steady.

But ya, I always seem to need to make tools for my tools and sometimes tools for my tools for my tools! It would be ridiculous if it were not so enjoyable.
 
$122US. That's $200 Cdn. Not happening Charlie!
It’s not a real project if you don’t buy at least one tool that costs 5x the cost of replacing the original item.

Even that is not without issues. I'd still have to drill it for the pin.....
There you go: you need to make a small shaft cross-drilling fixture, complete with hardened drill bushings.
 
Hmm
The bearing tips on the follow rest look familiar..
I have some used roller tappets. They look remarkably similar to those bearing tips…
I might have to dig them out and do some measuring.
 
But isn’t cool watching him single pointing 2-56 in CRS on what looks like a 14” lathe?

Yes, VERY COOL! I was flabbergasted! His first shot was pretty much what I expected. Not easy to thread a noodle......

But his micro follower clobbered that pesky little issue.

I like this concept: saves remaking the entire follower. If it were me, I’d use the bearing mount to attach the individual “backers.”

The bearing axles are pressed in pins. I didn't know that till I had a better look. Quite frankly, I think I'll add another item on my project list to make that a Stub threaded axle so I can change the bearing or insert a custom end ala this project. I'll call that item "Follow Rest Threaded Axle" or something similar. I'll also add a micro follow rest.

Setting that pesky little issue aside, I agree it's a better plan. Just need to make the Bearing axle replaceable first.

Joe used Linen Phenolic because the threads will cut into it without tending to transfer material into the threads (and he likes using this material :) ).

I'm thinking some kind of plastic would do the same. Maybe nylon or ABS.

But if you don’t use the original TPI you’ll need to modify the nut; if you’re going to do that you may as well up-size the diameter to make it easier to cut.

Can't increase the screw diameter. Won't go through the existing caliper legs which are already thin enough.

I was thinking I could rethread the existing nut from 60 to 56. That would jam over the length of the nut. But, if I drill out half the nut so it's just a tube, the remaining portion of threads might not jam.

Hey: you were the one who (foolishly? unnecessarily?) asked for opinions!

Not complaining Charlie. I like debate, discussion, and hearing other opinions. None of us is perfect and I really do treasure other opinions and input!
 
And from another corner:

I've seen Nano motors made at the molecular level. The motor in your link would look like mount everest by comparison. They are not hand made though. Both are WAAAY beyond my skill set.

Thanks Charlie!
 
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