1/100mm is about .0003". Over what distance are you trying to maintain that? Just curious as it shouldn't be a problem on shorter lengths with everything properly adjusted and aligned especially the saddle and headstock. I may have missed where you said but if you're saddle travel isn't perfect you're not gonna get .0003" unless you work only in the "good" area of travel. Then the headstock has to be done but anyway...
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The inner race of the inner bearing can be an interference fit on the spindle albeit very slight. Like tap it with a wooden hammer handle only to fully seat it.?
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?The inner race of the outer bearing should be a very snug slip fit on the spindle. That race has to be able to slide just like on a vehicle. ?It's fairly time consuming process. ?Sounds like your spindle wasn't properly fit for the bearing. If it was the race would move so you can set it. I think you're first step is going to be to rectify that and from there you're going to be set on that part.?
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On Feb 8, 2025 at 1:59?PM -0500, Pierre-Raymond Rondelle via groups.io <pierreraymondrondelle@...>, wrote:
Ryan, I agree with you and I'd like to add some comments.
Concerning the use of tapered bearings, my lathe came with them and I didn't touch them until I decided to get rid off a bad surface aspect. A little bit rough with a ghost wave of the same pitch as the lead screw. I slightly improved this situation but I can't manage to tighten the spindle nut enough to go further. Hence this thread.
On to the other hand, I'm not looking at a thou but 1/100mm and a good surface aspect and ... the very last 1/100 are extremely harder to reach !
Concerning a wheel hub, make the experience to put the car on a jack and twist the wheel. You will be surprised, the clearance is probably pretty greater than a thou.
On a mini lathe, the tapered bearings are there more for reducing the stray movements than to withstand loads. The sole difference I noticed is that on a wheel hub, the adjustment is very easy because the inner ring is not pressed in but slipping on the spindle. I found an explanation for that, please, read my other post.
On 08.02.25 07:05, Ryan H via groups.io wrote:
My tapered rollers have been in for 10 years. I haven't touched them in 3 1/2 years since I installed my els. I pulled the rear when I had the nuts off to install some parts for that and in the prior 6 1/2 years hadn't done a thing. They're fine and still as smooth as the day I installed them and maybe even smoother. ?The preload has never needed adjustment after a couple days of getting it set and my lathe will hold less than .001" over 12 inches. We're talking about bearings meant for vehicle use. Carrying 2 tons and absorbing constant impacts and lasting tens of thousands of miles. I packed mine with synthetic bearing grease. It's still there. Our little lathes turn a couple thousand rpm tops and how often are you running it wide open? ?And how long are you running it? ?We're not talking the equivalent of a hundred plus mile a day, five day a week commute here. We're maybe covering the same as a hundred miles a year, maybe. ?And at a lot less load. The angular contact are probably easier to install from what I've read as there's no need to sand the spindle for the slip fit tapered rollers require but either will last a lifetime with extremely minimal if any required maintenance if property installed.?
