Correct Operation of Micrometer Collars

[twooldvolvos]

I am new to machining and I have started out with a circa 1973 South Bend 10 K Lathe. So far I have enjoyed the steep learning curve. I have felt a connection with my father who passed several years ago before he had a chance to share his experience of machining with me. Today I have a question about the operation of my micrometer collars. Here is the micrometer collar of my cross slide.



With this one, I can turn the handle clockwise to take out the backlash and then loosen the micrometer collar screw and easily move the micrometer collar to any position I desire.

This is my compound micrometer collar.



With this one, after I take out the backlash by turning the handle clockwise, it pinches the micrometer collar in such a way that I cannot easily move it to lock it into a desired position.

Can any of you give me feedback on why my compound micrometer collar is hard to move once my backlash is taken out? Do I need a shim placed somewhere to compensate for wear?

FYI, I don't expect a 48 year old piece of machinery to work as new. But I am quite impressed how well my lathe has held up, all things considered.

 

[RJSakowski]

Probably because you have taken up the clearance between the collar and the frame. This is most likely due to a worn thrust bearing. Anshim washer or a new bearing should cure the problem.

 

[SLK001]

Yeah, it's jammed in tight when you took out the backlash. It can still be moved, but it takes more effort than the others. If you must move it, back off ~0.005", then move the collar to where you want it minus the 0.005". It also may have some debris in the works that is making it harder.

 

[.LMS.]

Someone also posted some good advice recently about backlash, saying it's not something you should strive to completely remove, you should learn how to live with a certain level of it. Not saying you (OP) should ignore it, just draw the right line in the sand.

And, how cool is that to go down this path of connection to your pops!

 

[twooldvolvos]

Probably because you have taken up the clearance between the collar and the frame. This is most likely due to a worn thrust bearing. Anshim washer or a new bearing should cure the problem.

Thanks for the feedback. I will have to research where and what the thrust bearing is and how one would go about replacing it.

 

[twooldvolvos]

Someone also posted some good advice recently about backlash, saying it's not something you should strive to completely remove, you should learn how to live with a certain level of it. Not saying you (OP) should ignore it, just draw the right line in the sand.

And, how cool is that to go down this path of connection to your pops!

Good point. I am not nieve enough to think that a 50 year old piece of equipment doesn't have some wear on it.