Author Topic: Mini Lathe Tapered Bearing Mod - Finished By Elves  (Read 2273 times)

Offline builditbackwards

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Mini Lathe Tapered Bearing Mod - Finished By Elves
« on: September 26, 2014, 10:11:20 PM »
Hello, fellow addicts. This is maybe not the best board for this thread, if there is a better place, then by all means move it. If anybody could please tell me wtf is going on, Ill name my next dog after you.

I finally decided to swap out my bearings and mount the steppers I bought back in febuary or march, 425oz/in torque, pro driver board, obese power supply- nice stuff, but no match for laziness. I did a lot of reading wrt the bearing swap. I was never quite satisfied that I was prepared, since it seemed that there were several versions of not only what to do, but how to do it. I keep reading about and seeing parts for hi/lo gear shifter on a counter shaft and other things that should be in my 7x14 mini lathe from Little Machine Shop. Now I know that HiTorque is a type of drive system based on a brushless DC motor.

I do not have a second lathe, so I was prepared to modify my spacers by any means nessesary, which I didnt expect to be too god awful difficult. Nylon rubbed across some 220 grit emery, lubed up with a few fat sprays of WD-40 will peel off .005"-.01" pretty easy every few strokes. One of the first things I did when I got the spindle apart and bearings off, was to throw em on the surface plate and hit the old ones and new ones side by side with my indicator, .049 and some change, made me feel good about my indicator lol. The data sheets support this by also reporting a difference of 1.25mm difference in length with the tapered bearings being the longer of the two.

So, I put the whole thing back together with no modifications to the spacers. The problem is, everything is still lined up perfectly. The only possible solution I can come up with is the manufacturer didnt push the rear bearing as far on the journal as it could have went. Almost as if in anticipation of this upgrade. All I know for sure is that I havent did a thing to my spacers or made spacers for the motor pulley, yet the motor pulley lines right up with the spindle pulley does a fine job right where its at. What should I think of this? Aliens? Here's some pr0n so you can see for yourself.



Now that youve seen the proof, here's a smattering of random pr0n from the job-

Its setups like this that are gonna break me off doing machine work barefoot.


I did manage to make me a bed guard. I should have done it long ago says the heinous hack saw scar being hidden by the nice piece of wood and foam






Still tinkering with ideas on where the Z axis stepper is gonna go. Even inside the control box is being seriously thought about.

Offline builditbackwards

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Re: Mini Lathe Tapered Bearing Mod - Finished By Elves
« Reply #1 on: September 26, 2014, 10:36:02 PM »
I forgot a couple things I should maybe mention. The rear bearing journal was a few tenths out of round. Hand polishing that diameter did little more than exaggerate any error present. Now I have a spindle running out .0015". It was .002" but some shimming got rid of a few tenths lol. Im on the fence about ordering a new spindle. Theyre cheap enough, besides, Id like to grab some good high end bearings with a quality ground new spindle of the 100mm/4" variety.


Offline Stilldrillin

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Re: Mini Lathe Tapered Bearing Mod - Finished By Elves
« Reply #2 on: September 27, 2014, 04:10:01 AM »
Hi Buildit.
I'm with you!  :thumbup:

A long time ago, I removed the spindle, leaving the spacers inside.

Then fitted roller bearings...... http://madmodder.net/index.php/topic,1292.0.html  (Just read the first pic area).

The only spacer which needed modding, is behind the tumbler gear.
I later fitted a steel one..... http://madmodder.net/index.php/topic,7643.10.html  Which made an even greater improvement!

Still running sweetly.........  :D

David D
Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!

Offline builditbackwards

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Re: Mini Lathe Tapered Bearing Mod - Finished By Elves
« Reply #3 on: September 28, 2014, 03:10:08 AM »
Got it within .0002". Time to make some parts.

Thanks, stilldrillin, for letting me know Im not crazy. Im gonna stick with the alien scenario for now, though.