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How to determine the condition of bearings in a 10ee, and other questions

Hmm - I might be fundamentally missing something. It would seem to be that 1) the rear bearing is only offering support for the back of the spindle - not a precision operation like the front bearings, though maybe this is incorrect (please correct me if this is not the case). 2) the amount that the spindle race is off (.0001-.0002") is inside of what the tolerance for the ID for a 5210/or 3210 precision bearing would be anyhow - or am I missing something? If the fit on the spindle should be an interference fit, I can understand that this isn't likely to be ok, unless I can find a bearing that is at the lower edge of the tolerance limit, but it would seem that this should be an accurate slip fit, but not necessarily interference fit. Then again, I'm not an engineer, so I may be just missing the boat.
Ah - I see Bill. I get where you are coming from. I can understand that.

I was thinking about it a little bit, and I had a little thought about the situation:

The rear bearing has a nice slip fit in it's bore (O.D.). I don't see any slip marks on the outside of the bearing, or in the headstock casting - it appears to my novice eyes as being as originally made. Therefore, the original fit of that bearing on the spindle must have been also nothing tighter than a slip fit because if it were a tight fit, when the bearing locked up, it would have been more likely to spin the outer race in the headstock, rather than around the spindle. That would mean that the original spindle fit was looser than the bearing in the headstock. That's just a theory, and maybe there are factors that I did not accurately consider there. While it seems unfortunate that it happened at one time, when feeling it with my fingers, and measuring it with the mic, I don't get a gut dropping sensation that something is particularly wrong. Clearly, something DID happen back there, but it doesn't strike me as catastrophic.
Thanks Bill.

I'll do some more advanced searches regarding spindle bearings, fit and the like. Believe it or not, I have spent quite a few hours reading about various topics here. I sort of hate to think about how much time I've spent over the years, actually - probably in the thousands of hours if I counted it all up, just here, not counting other places on the web. I've actually tried to spend quite a bit less time on the internet the last couple years - it's been great. All that is an aside though. I'll do some searches relating to that. I think it's good to try and think for oneself in these matters as well, and use searches, and advice as corroborating or contradicting information to challenge ones original assumptions. I tend to be a bit expository, so that might be taken as not wanting to do the work, which isn't the case.

I think your statement should be revised to "word FROM the wise in this case, to the, well, sumthin'..." (less wise, at the least). :) I've never had my retention rate measured - I'm guessing it's about 60% in the first minute, with a steady decrease of 2% per minute after that. Wait, what is this thing I'm looking at? Who are you? Why am I not wearing any pants? (No offense meant to the legitimately memory impaired)
Well, I can't crack it loose tonight - it won't budge, and I want to get a better wrench - mine is too small to be as effective as I want it to be.
You might try attaching one of your chucks, preferably a big 4-jaw, so that you can clamp the spindle to something and get better leverage with the wrench on the spindle nut. But, were it me, I would leave that part alone until I at least tried it with a new rear bearing. It may be plenty good enough without messing with the front bearings. Bringing a well used 10EE back to new condition is an expensive and time consuming process...

You might try flushing the front bearings with fresh kerosene or mineral spirits to see if you can clean out the grit that you're feeling.

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"...There's your problem..."
Yikes, a zombie in the shop, RUN AWAY!! :eek:

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Front spindle bearing area

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Just behind front spindle bearing area, looking down. The front weep hole (exits front of headstock) ends right into this space. It surprised me a bit - I thought it would end up somewhere else, for some reason.

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Welding rod showing trajectory of weep hole, which goes underneath the front bearing cavity, and into the next headstock space (see picture in previous post). ...

Oh and Cal - I couldn't find ANY external hole from the main headstock casting front bearing cavity to the outside, save the sight glass window. …
Let me make sure that I understand: the hole at 6 O'clock goes straight through and exits in the center reservoir? Is that right?

Are there passages in the front bearing retainer plate that lead to the passage under the front bearing reservoir?

Thanks for the serial number information and the extra photos. Keep 'em coming!

Hi Cal,

If I understand what you are asking, then yes - that front hole (with the welding rod) goes straight under the front bearing reservoir, into the next chamber over - where the spindle tach fiber gear is. I haven't found any holes in the front bearing headstock casting area. It's a sealed tomb. I will look at the round front plate that attaches to the headstock to see if there are holes of some kind in there, other than the 6-oclock weep hole.

I just got the 5210 in the mail today - appears to be a full bearing compliment, with the little cutout in the race (just like the original). Boy, that thing seems to just fit about perfect, assuming it should have just the tiniest amount of "stick" to the spindle.
Spindle relate notes from other posts:

"It's been too many years to remember details about fits without going back and researching. But I recall that Timken recommended for spindle assemblies similar to this where you had TRB at each end of the spindle, the first bearing on the spindle was a interference fit. The last bearing on was a snug fit, small interference to about .0005" loose. this pretty much followed on any spindle assembly similar to this, rather it was two single roll bearings used or two double roll bearings used at each end of the spindle.

"The front bearings are held, the rear set is loose. That is normal. Get the shaft and bearing bore dimensions and compare that to the tolerance for your class of bearing. If the shaft is out of tolerance Locktite makes a filler, not red or blue."

"If the rear bearing is a 5210 replacing it is not going to fix deflection if that bearing is free floating in there as I suspect it has to be (to allow for spindle expansion)
A modern 5210 bearing is not preloaded at the factory and has internal clearances.. I suspect the old 5210 bearings monarch used, did have factory installed preload..
If it has a pair of duplex 7210 bearings in there, they are preloaded..."

This is reference for me, more than anything else. If these statements hold true for the 10ee spindle, than I believe the burnish on the rear spindle journal is not a significant problem, as the new bearing fit is consistent with these statements.
I removed the spindle nut - I just needed to get a better way to hold on to the spindle - Bison 2-position pipe vise clamped to the tail end of the spindle tube did nicely. That nut was on their TIGHT. I am suspicious of the tightness, though maybe there is a legitimate reason for it.

I haven't figured out a way to non-destructively remove the bearings. Heating isn't a realistic option, as the ball separator is a fiber/resin type, with limited temperature tolerance. The other option would be to press the whole shebang off, using the front plate as the pushing surface, but that seems risky to the spindle itself, without having first expanded the bearing to loosen the fit. I'm going to consider removal a last resort. I ran across mention of using 250°F oil poured on for thermal differential, which was an interesting idea.

There were quite a few pieces of metal that I was able to remove from the rearward bearing. Yikes! I was able to carefully tap the outer spacer around, to get access to a small portion of the front bearing at a time. I cleaned what I could, but there's more in there. The bearings are smoother now, but if I could come up with a way to clean it all out, I think it would feel better yet. I just don't know how to do that. yet.

Cal - the only vent to the first headstock chamber appears to be through the bearings, out the space between spindle and the front plate, and then out a little weep hole in the front plate casting. Draining the front headstock chamber fully would appear to be near impossible without tipping the machine on it's side, or pulling the spindle. Or using some type of vaccum aparatus, which would seem a bit silly. It's quite strange.

I'm not clear on where the weep hole(s) in the front bearing retainer are. Could you post a photo or two with rods or wires to mark the entry and exit holes?

Hi Cal. Yes! I will do that.

I spent the evening cleaning, and putting the spindle back in. While I was at it, I poked around and discovered that the shift fork (thread selector) bolts were not tight, and that the tach bevel gear was not tight. I turned it on, not expecting much, and sure enough, I wasn't dissapointed (well, maybe a little). The noise is the same as before. At first, it seemed as though it was going to be quieter, but then it returned. I don't know if it was wishful thinking that for a moment it seemed quieter, or whether it really was the case.

I took a test cut, same issue.

The sound is so dang harmonic. I laid my ear on the machine and poked around all over the place. It's strange - when my ear is directly over the front bearing, it's not too loud (though definitely still audible). When I position over the rear bearing, it's also not too loud. But when I'm over the larger central cavity, man is that sucker LOUD. On the one hand, it might be perhaps due to it being a larger, more resonant chamber. OR it's because the sound is really coming from there. The only think I can think of that it could come from would be the tach gears (Super, duper, long shot), so I'll try removing those tomorrow, just to try and eliminate as many variables. If I remove the tach gear, and that doesn't change anything, I'm heading down the road of needing to replace the front spindle bearings (paging RC99!), that is if I can come up with a good way to pull the existing ones without damaging either the spindle or the spacers. I've searched, and haven't come up with this exact scenario yet. I'll keep looking.

Interestingly, there is another fiber gear that meshes with the spindle fiber gear. It is directly below the spindle. It isn't obvious to me what it's for. I can see it in the Monarch headstock assembly drawing (part EE-1105). Is it just to draw up oil onto the fiber gears from the reservoir below? It doesn't appear to drive anything, far as I can tell.

More pondering, more reading, more poking around. It's a good problem solving exercise, I'll give it that!
My EE is different than yours. But what I did to remove my front bearing reinstall it without the lockring then gave it small taps with a dead blow. My bearings weren't that tight on the shaft. That way the shaft is supported both front and back. use the old bearing in the back. My lathe is a tapered roller model. Don't hammer on your shaft to hard or you'll dent the races. Bob
If I remove the tach gear, and that doesn't change anything, I'm heading down the road of needing to replace the front spindle bearings (paging RC99!), that is if I can come up with a good way to pull the existing ones without damaging either the spindle or the spacers. I've searched, and haven't come up with this exact scenario yet. I'll keep looking.

If you do go this route, here are photo's of the ones I have.. Just be aware only one has the high spots marked on the inner and outer ring.. I do not know why that is, but I have had the spindle of mine out and measured up the bearings and they are the same plus the hand written suffix and prefix letters on the bearing all check out as being correct, that being duplex, medium preload, universal ground, ABEC5.


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It turned out to be a pretty nice day today, so I went on a little bike ride (until my buddy pulled a face slapper on some frozen dirt). I haven't pulled the tach stuff yet, but will try to do that tonight. If that doesn't fix it, I would seem most plausible that the front bearings are bad. Richard - I would happily pay you for the bearings you have. I'll PM you about them for payment method, etc. Did you ever pull the bearings in your machine? If so, did you use a method similar to Vettebob (which was intriguing), or some other method of removing the old bearings? I thought about suspending the spindle on a wooden frame , such that the bearings sat in warm oil. That way, I could rotate the spindle, and warm the bearings until they expanded enough to be removed. Seems messy, but messy is all right if I get them off without causing damage to the spindle. I don't know how firm the spindle and front bearing interface is. I know some of the other components do NOT want to come off with out differential expansion (such as the aluminum pulley and spindle lock ring).

I just remembered I did remove the bearings from my 10EE and found the photos.. How I did it was remove the locking nut, then upend the spindle and tap the end fairly hard onto a solid block of timber.. The bearings will slide off and should not be damaged...

Installation is through a long very clean tube that only bares on the inner ring.. after reinstallation of the bearings and spindle on my 10EE I still had the same sub 0.0001" run out and same very good surface finish..
Thanks Bill - I have the cover off now and will observe that dog clutch now to see if it does anything like what you mention. Thanks for the suggestion.

I ended up purchasing the bearings from Richard (RC99). I am quite thankful that he was willing to sell them, and for the price as well.

I pulled the upper fiber gear and ran the machine earlier - still made noise. Vettebob is right, I'm pretty sure that lower fiber gear is there just to sling oil onto my safety glasses. I was thinking that if that fiber gear runs on some small bearing down in there, I might as well replace that sucker while I'm at it - I've done many of the others. I'm going to try and replace all the idlers and bearings (or at least true the idlers, and replace the bearings), and true the sheaves as well. The lower one has some wiggle to it.

I still haven't taken photos of the weep holes that Cal mentioned. I haven't forgotten about that - I will try to do that tomorrow. When I dive back in, in a couple of weeks for the bearing replacement, let me know if there are any photos/measurements that anyone needs wants while I'm in there.
Good call on new spindle bearings, the moment you noticed notchy behavior from them sealed their fate. I'm sure you know they are under considerable preload as installed to provide stiffness for the spindle bearing system, it's a carefully designed system. Any trash in them rolled over by the balls develops pressures high enough to damage both the races and balls, hence the source of the rhythmic noise you observed. Corrosion can cause it too but you found trash in them. I vote for trash.

It's not clear if you purchased the ABEC class 5 or class 7 bearings. It won't matter to casual users between the two, however if one needs what a 10EE is capable of it does indeed matter. Let us know where you are on that spectrum.

Cleanliness is paramount with precision rolling element bearings, installing expensive new bearings into what is currently a dirty headstock would be an error. You know the current bearings were ruined, prevent the situation that caused it. Big job to clean it all up but that is what it takes. The inside of your headstock: clean to better than you'd eat off.

Your machine was abused, the dog clutches proved that.

It might seem silly to vacuum out the bottom of a bearing lube cavity but rest assured there are some of us who do exactly that. And we know why it's necessary.
In my case, I'm confident that the ABEC 5 bearings will be sufficient, and in fact, they should be a large improvement over what I've got currently. I can understand that for the work that some might do, a higher ABEC would be required, but not in mine! I primarily do fabrication work, where the lathe supports that through making tools, and production turning of small, simple parts, such as acetal bushings, boring tubular parts, etc. I certainly won't turn my nose up at higher accuracy, but I believe that those ABEC 5s will restore the machine to well beyond what I've previously ever had. I'd love to hear some stories of parts made on 10ee machines where that level was required - I'm sure it's happened, and it would be very interesting to hear some accounts of that.

Cal - I took a picture of the weep hole on the front plate but realized that I didn't quite get it right - the weep hole must go to the passage that goes under the front bearing cavity into the large headstock cavity. The only passage then from that front bearing cavity on mine would actually be through the space in between the spindle nose and that front plate. I'm assuming my front plate is similar to others, but I'll submit the photo for reference just in case it's useful somehow. I'm curious if on other machines there is a passage from the front bearing cavity to the outside. Is this known to be the case, and my machine is a bit of an oddity that way (at least as far as anyone knows)?

Shift fork bolts were loose here.

Weep hole where welding rod is pointing.
I have seen pictures of other 10EE's with that drain hole...

Oil is not supposed to come out there, it is an overflow should the return hole get blocked.. On my 10EE it does not have that drain hole as it predates it and when I got it, oil came out from around the spindle nose.. When I pulled the spindle out, the return hole was blocked with a grease like substance, and oil would go in that area, and could not return to the reservoir and came out around the spindle nose instead... It is fixed now...

I personally would keep some paper towel in that hole... That area is not the place you want any dust or muck to enter, even though the chances are rare...
Hi Bill - Is there any chance that on your machine, the shaft that runs into the headstock from the selector could be off by a tooth? If I recall from looking down in there (don't quote me on it, my memory is NOT good with stuff like that), the selector engages a gear 90 degrees to the selector shaft. If it had been pulled out, and then reinserted 1 tooth off, would that explain your issue? Just wondering - I might be totally off base.