Timken Bearing fit question

Thank you all for the feedback. I’ll measure the spindle and the bearings and report back what I find. I had considered heating the bearings but wasn’t sure of how much to heat, so thank you tertairyjim for that info. I’m eager to complete the assembly, maybe tonight after the kids karate classes.

Thanks again
Jude
 
In a single cup installation Timkens can stand a lot of press fit on both cone and cup because the final take up is the end play, what they do not tolerate is out of round
 
As I wrote earlier, although one would think from the way in which the end float is adjusted that the cone is going to be at most a light push fit on the spindle, any number of reports indicate that isn't always the case. I would make a puller from a length of 5/8" threaded rod (UNF if you can find it), a length of structural tubing with ID just slightly larger than the left end of the spindle, a shoulder washer to fit the tubing and one to fit the right end of the spindle. and some coupling (long pattern) nuts. Or put the cone in something like a roasting bag and immerse it in boiling water for 15 or 20 minutes. Carry the pan with the bearing to the lathe, take the bearing out of the water and out of the bag with an oven mitt and slide it onto the spindle and hold it and the spindle together until it cools off and locks. Load the spacer, gear and threaded collar on the spindle. Use a dial indicator to check end float, tightening the collar a tooth at a time until it goes to zero. Then two more teeth for preload and tighten the set screws.
 
I rebuilt high speed spindles and also have rebuilt the spindle you are referring to with a press fit on the rear bearing you won't be able to adjust the spindle end play. Tha t rear bearing has to be a push fit in order to adjust.
 
I managed to measure the bearing and the spindle tonight. The bearing was 1.2450 and the spindle was 1.2490. I heated the bearing and was able to get everything put together. The bearing was a tight fit, I was able to pull it on with a threaded rod and spacer tool. Thanks for the help...
IMG_7747.jpgIMG_7749.jpgIMG_7748.jpg
 
Glad you made out. That's one fine looking head-stock.
 
And you remembered to put the belt on first - Win Win. Looks good.
 
markba633csi said:
As John mentioned the left bearing should be a light interference fit but it may require you to put together a threaded rod and spacer tool to
pull it together. That would be preferable to hammering it in. Use oil too.
Click to expand...

I know this is an old thread, but I wanted to say thanks! I've been struggling with the same tight (REALLY tight) fit on my Atlas 618. I was devising a way to use an F-clamp over the top of the headstock but a threaded rod is just so much simpler and easier to align.

I had tried heating the bearing using the old light bulb trick. It was way too hot to hold and yet stopped moving about 3/8" from home. I think the heat migrates quickly from the bearing to the spindle and there is no longer any clearance.

Since the process is anything but easy, I've decided to replace the bull gear while I'm in there. I _could_ make the old one work but I don't want to have to do this again in my lifetime!

Thanks again.

Craig
 
The threaded rod method for reinstalling the spindle bearings should if possible be used up to the point where you have reduced the spindle end float exactly to zero (as measured with a dial indicator). Then follow the instructions in the Atlas Technical Bulletin on the Atlas 06 612... by installing the threaded collar until tight and then advancing it by 1/16th of a turn or two teeth of the 32T spindle gear. This preloads the spindle bearings by a little more than 0.002" and ensures that the bearings do not go loose when the spindle length grows slightly as it warms up.
 
I haven't seen yet how to measure "spindle end float". Could someone point me to a write-up or summarize? I do have a couple of dial indicators. Thanks,

Craig
 
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