New Lathe User - Just Bought An Atlas MK2 6x18

Hi Guys - back again, I'm starting to play around with machining some aluminum and the cross slide hand wheel seems to have what I think is a lot of slop in it. It turns about 30, maybe 35 degrees right or left before it starts moving the cross slide. This brass(?) nut fits tightly into the hole in the cross slide, so the play must be in the threaded part that the screw drives. Is this nut (what do you call this thing?) worn out, or is this normal for these machines?

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The nut fits tightly into the hole then is fastened by a screw which also holds a cover plate in place.
It's normal to have some backlash on the order of what you are experiencing. Anticipating (and compensating for) backlash is part of the learning process.
Mark S.
 
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markba633csi said:
The nut fits tightly into the hole then is fastened by a screw which also holds a cover plate in place.
It's normal to have some backlash on the order of what you are experiencing. Anticipating (and compensating for) backlash is part of the learning process.
Mark S.
Click to expand...

Yep, it's a pretty simple device.

Looking at it some more it's clear that the play/backlash isn't because of a loose fit of the nut in the hole in the cross slide (it's tight) or because of the threads in the nut (look fine, minimal play when screwed onto the drive screw). It's because the brass nut is relatively narrow compared to the slot in the carriage that it and the drive screw ride in. There's about 2-3 mm space on each side of the nut, so when you turn the hand wheel the nut rotates either way before it contacts the side of the slot and only then actually starts driving the cross slide.

Seems they would have manufactured it with tighter tolerances. Ok, if it's normal I'll try to back off my AR-OCD perfectionist tendencies, LOL.
 
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If the nut is moving/rotating something is wrong. The screw and cover should hold the nut firmly (if I remember correctly) to the cross slide.
Check that the nut isn't extending above the top surface of the slide, it should be just below the surface.
I don't see the cover plate in your picture- you do have one correct?
Mark
 
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Alright, I'm stupid, sheesh, ignore that post please, sorry. Too early in the morning and not enough coffee. You're right markba....

edit: yes, do have the cover plate.
 
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great lathe i wish I got tooling with mine ,so far i've spent 350 on mine 200 more plus a new chuck and qctp 350.so thats 900 not bad 75 dollar investment LOL. you did well
 
Is it possible you are getting the backlash because the preload on the screw needs to be tightened up ? Ie: Turn the cross feed handle in and then back out so that you are at the backlash point look at the cross feed dial , is there a gap where it meets the slide ? When you turn the handle back in , does the gap close up and then move the slide ? If that is the case can you tighten up the dial to get rid of the gap ? Hope that makes sense , that is the fix on my 6" Craftsman .
 
Thanks westsailpat! I figured out what you're talking about. There was a very small gap, so I tightened up the nut on the dial as much as possible but still allowing smooth turning. Now the backlash is about half what it was. :encourage: Still there, but less.

Given the very small amount of wear I can find on this machine I'd think the carriage cross slide brass nut shouldn't be worn much on the internal threads, but maybe a new one would tighten it up even more.
 
Wow OK that worked , so now you are down to about 15* ? I don't think I would be worried about that . I like to run a little oil in the gap . Every threaded type lead screw has some backlash to some degree .
 
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