Spindle bearing woes

Hi Izzy,

I don't see a 3 thou high spot as an issue. You will get that anyway because that is where the oil feed is.
 
So you say I shouldn't try to polish out that 3thou? Or the rest of the bearing surface to smooth it out? Just sand the bearing smooth and hone it to size? I could shave a bit off the caps as suggested by @pontiac428 with my Bridgeport.
 
It could be nothing but the bearings being so out of round and tapered like they are worries me. Also Due to the thrust face wearing out the high spot on the spindle doesn't spin in the center of the bearing anymore it's pushed back by about a 1/16.
 
Izzy, The 3 thou is nothing ! Don't even bother about it.

As far as shaving anything off the caps or bearing for that matter isn't going to improve things. You have already said that the spindle binds up when you remove the shims ! In that case you need to add shims in order to reduce the effects of any wear.

Assuming your measurements are accurate the variation that you see in the caps is because they probably were not tightened down evenly. Again the few thou difference could quite easily be due to the bearing cap being slightly twisted when fitted. They are not doweled so there is no saying that when you replace them, that they won't end up being in a slightly different place.

I wouldn't worry about the bearings being slightly out of round ! They will never be truly round. Worn thrust faces are another thing altogether.
You may need to make bronze thrust washers to sort that.

But lets do one thing at once.
 
@BaronJ thanks I appreciate the help so far! The lathe was restored about a year ago I did it myself and at the time nothing was done to the bearings other than shimming them to get proper oil clearance. I torqued the caps down myself so I know they where done evenly as I used a torque wrench. I measured the step for the bearing cap it seems like the cap itself is what's tapered not the bearing. Looks like this problem is unraveling itself...IMG_20180928_173104.jpgIMG_20180928_173136.jpg
 
My thoughts with the spindle binding up without the shims was that I could remove the shims and take out the extra material that causes it to bind. I just need to have this back up and running a bit longer. Then when the time comes, do as Pontiac said and have a shop skim the caps and line bore it back to size.
 
Hi Izzy,

You need to think very carefully about this, once you remove material, thats it, you cannot replace it !

When the lathe was made originally, the bearings and caps were deliberately made with shims, not because they were cut wrongly, but because things wear. The shims are there so that the spindle clearances can be adjusted to account for the inevitable wear that will take place over time.
The shims are usually, but not always, a stack of very thin ones, often only a thou or so thick, they can seem like one solid shim because they are compressed by the cap and tend to bond together.

The normal way to adjust the bearings is to remove one or two shims at a time, measuring the spindle rotation as you go.
When the spindle becomes more than hand tight, put one shim back, and check again. It is not a quick process ! I've seen engineers take days to shim shaft bearings. This is why I suggested feeler gauges earlier, in case the shim was solid and not a stack. Even compressing out the surface oil between the shims will affect the clearance.

Whilst I think about it ! Carefully clean the oil drain hole in the bottom bearing. The oil must have somewhere to drain. Remember any dirt that gets into that top oil cup will get into the bearing and cause the scoring that you talk about on the shaft, and lack of oil is even worse because particles of the bearing itself will cause scoring.

When you put it all back together use plenty of clean oil, 10 or 20 SAE motor oil is perfectly fine. If perchance you use multigrade, oil, do not mix it or allow it to mix with detergent oils. It will turn into a paste that won't lubricate anything.

I'll come back later and discuss thrust washers with you.
 
Yes I understand about the shims being there to take up wear over time. This is why I measured without the shims because at that point you've used up all your adjustment and need a more permanent fix per say. The thrust washer I can remake myself once he bearings are good enough I can use the lathe again. I would one day like to do a "real" restoration and get the bearings done properly. I really like this machine and I feel like if I had the bearings done properly the machine would cut much better and last another 100 years. I tried honing the bearings yesterday and i managed to remove alot of the scoring without affecting hole size too much.
I've been using iso32 hydraulic oil on the bearings.
 
Also that isn't an oil drain hole, I thought the same thing but that's actually a pin I can only image to prevent the bearing from spinning. Oil simple runs out the sides of the bearings and honestly it runs through oil like crazy which is just one more reason I want to get this bearing situation all sorted out
 
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