Mini Lathe Cross Slide Bearing Mod

Not sure about the bearing size for the back of the bushing that's up against the compound. The bushing is much smaller in the back as can be seen in the second photo where I have it turned on its side. It seems to me that I'll have to find a small diameter bearing that would fit, otherwise I'll only be able to fit a bearing in the front or will have to make or find a different style bushing that attaches in a different way that can house a larger bearing in the back which may not be worth it.
 
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If anyone has added 2 thrust bearings - 1 in the front and 1 in the back of the cross slide retainer like the one below - on a 7X14 mini lathe, or fabricated a new retainer that houses 2 bearings that will fit the 7X14 mini lathe please explain how you did it and the ID and OD bearing sizes you used. Looks like an easier project for a larger lathe. Thanks.480.1386.jpg
 
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Are the bearings tightly press fit onto the leadscrew shaft?
Did you use grub screws to lock each bearings' outer edge to the neck?
Does the leadscrews' flat/shoulder rub against the cross slide or do you have some sort of teflon washer between them?
 
No they do not press on the shaft. I made a 7/17 lead screw so I used 7/16 bearings. The bearings are a more or less an interference fit in the mount. I used a trick I got from Billgruby (believe thats how it's spelled). He's a mod here. What I took away from what he said was to bore the hole till your 5-10 thou out from what you need. Then take a thou and set the bottom of the bearing in the hole and roll the top in. Take another cut and try again. When it's just right the top will fall in. Once cool it seemed to tighten up just right. But a screw could do it. But just try to sneak up on the number you need. Get close and fit it after every pass till it's perfect. When I bore to a stop like that I dont bore all the way to depth. I leave a touch in the back for clean up so you have a nice flat surface. That way if you go to deep or shallow on this pass or that, you can clean it up at the end
 
I was thinking the inner bearing needed to be a tight press fit on the leadscrew so it would turn when the screw is turned and there wouldn't be any "play".

I just ordered some 1-1/2" aluminum round stock to make a bearing housing prototype. I'll precisely measure the leadscrew shaft diameter again and order some bearings. They're inexpensive so I'll get a few different sizes to try. All will probably become clearer in the physical fabrication process rather than theorizing all this in my head. I'm so curious to see how the bearings will reduce enough friction for me to turn the handles smoothly while the gib is tight. Seems like there are other metal-on-metal friction points that the bearings can't cover, but I won't know for sure until I try it out. Maybe I'll add a bearing to the topslide first because that seems simpler but the concept will be similar. I'll take pictures and post my progress.
 
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Mini Lathe Cross Slide Bearing Mod - SUCCESS!

I finally took the plunge and installed a ceramic bearing in my mini lathe's cross slide bushing and the difference is incredible. I can tighten the gib and still have smooth operation. My backlash went from .010 to .002 and my facing finish, which was already good, is even better. I also added a set screw to the bottom of the bushing to make sure the bearing's outer race was locked in. What a great, simple mod!
 
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ehamady said:
Mini Lathe Cross Slide Bearing Mod - SUCCESS!

I finally took the plunge and installed a ceramic bearing in my mini lathe's cross slide bushing and the difference is incredible. I can tighten the gib and still have smooth operation. My backlash went from .010 to .002 and my facing finish, which was already good, is even better. I also added a set screw to the bottom of the bushing to make sure the bearing's outer race was locked in. What a great, simple mod!
Click to expand...

Can you provide details on how you completed the mod? I am going to install the extended travel lead screw from LMS and might as well install some bearing while I have it all torn down. Details on the bearings would be great.

Thanks,

Brooks
 
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