Atlas milling machine refresh project

[wa5cab]

I'm sorry but pressing a cup in with a cone is a bad thing to do. Although you don't care about any damage done to the old cone, you could damage the new cups. A tapered roller bearing cup only has nearly zero width line contact with its cone. Which means that if it took (just to pull a number out of the air) 100 pounds force to press the cup in, that force is concentrated on much less than 1% of the cup surface area. This extreme concentration of force leads to what's called "brinelling". Which means work hardening of the surface of the cup along however many very narrow lines as there are rollers in the cone. The potential damage is not as severe as with ball bearings, where you have only point contact, but nonetheless can be significant. The proper tool with which to press a tapered roller bearing cup in is ideally a flanged truncated cone with a flange OD just slightly less than the OD of the cup. A reasonable substitute is a thick flat disk of just slightly smaller OD than the cup OD with a cylinder (or two or more disks) on the front of just slightly less OD than the minimum ID of the cup.

Robert D.

 

[VSAncona]

I'm sorry but pressing a cup in with a cone is a bad thing to do. Although you don't care about any damage done to the old cone, you could damage the new cups. A tapered roller bearing cup only has nearly zero width line contact with its cone. Which means that if it took (just to pull a number out of the air) 100 pounds force to press the cup in, that force is concentrated on much less than 1% of the cup surface area. This extreme concentration of force leads to what's called "brinelling". Which means work hardening of the surface of the cup along however many very narrow lines as there are rollers in the cone. The potential damage is not as severe as with ball bearings, where you have only point contact, but nonetheless can be significant. The proper tool with which to press a tapered roller bearing cup in is ideally a flanged truncated cone with a flange OD just slightly less than the OD of the cup. A reasonable substitute is a thick flat disk of just slightly smaller OD than the cup OD with a cylinder (or two or more disks) on the front of just slightly less OD than the minimum ID of the cup.Robert D.

I was kind of wondering as I was doing it if it was a good idea or not. Unfortunately, I didn't have a spacer the right size to press them in. There's not much of a shoulder on that end. I actually got a couple extra cups, so maybe i'll try it again. I'll take the photos down so I don't give anyone any bad ideas.

 

[VSAncona]

Okay, let me try again. I have two extra cups that I've been saving for my Atlas lathe, so I decided to replace the ones that I just put in, just to be safe. I had some time this morning before taking the kids to school to give it another shot. I looked around my shop for something I could use to make a pusher for the cups. I didn't have any aluminum or steel large enough, but I had a chunk of Delrin lying about, so I faced it off and turned a shoulder on it to just barely fit in the bore of the headstock:



Then I used that to press the cups into the headstock bores:



Hopefully, that didn't do any damage to the cups and I can move forward with putting the rest of it together:

 

[frbutts]

I am looking forward to pic's when finished. Great job so far.

 

[34_40]

While "technically correct" you aren't building a space shuttle, those bearing cups would've lasted a long time before you noticed anything amiss.. but you've rectified the issue nicely! Good Job.


I like the oil cups you've added too. I want to investigate mine tomorrow and see if I can copy yours. TIA

 

[wa5cab]

34_40,

You are probably correct that VSA could probably have gone ahead and used the cups that were installed using the old cones. But at least now, there's no question to worry about. It partially depends upon how much force was applied. FWIW, Harbor Freight (and probably others) sell a set of cup drivers made of aluminum. But I don't know for certain that the set includes one of the proper size. KD also sells a set, which is likely better quality. And has more sizes. But it wasn't cheap like the HF set.

The spindle oilers are, unlike the ones on the 10" and 12" lathes, standard Gits oilers. I'm puzzled as to why so many mills seem to be missing them. They are on the parts list (under an Atlas part number) and I can't imagine Atlas shipping a mill with them omitted.

Robert D.

 

[VSAncona]

I was thinking about the issue of installing the cups and it dawned on me that Atlas' instructions for removing the spindle to replace the belt are to whack on the outboard end of the spindle with a soft mallet, thereby forcing the outboard cone against the cup and driving the bearing off the spindle. The instructions don't say anything about replacing the cup after you do this, so apparently the engineers at Atlas didn't think it was an issue. But I suppose I don't have to worry now. The cups are pretty cheap on eBay.

I was kind of puzzled as to why my mill was missing the oilers as well. It's also missing the little ball oiler in the arbor bearing that fits onto the end of the overarm bar. Someone would have had to go to a little bit of effort to remove these oilers, so it makes me wonder if they were just never installed at the factory to begin with.

 

[34_40]

"Beating" out a bearing is very different than pushing one into position with a press. After beating it out, I'd toss both parts.

No matter, you're in fine shape now.

I think I need to review the manual and specifically identify and verify these lube points and the condition of the components (if present!).. The timing of ths topic is perfect since I just got mine running. So thanks again!

 

[34_40]

Took a look in mine and discovered one oil cup in place and the other is gone. I wonder if it would've gone into the bottom? If so, could it be easily retrieved?

 

[VSAncona]

If you can't find it, Amazon has them. They were around $4.00 apiece.