Stuck part on spindle cartridge

How does PN 14 (BOSS) come off? Isn't it just a straight pull? looks like the shaft should have a taper and key.
I will need to remove the small upper key once I get the BOSS moving, i expect that.

Thanks!

If you're talking about removing the large gear mount/conical cap that's labeled "14" in pic #5, there's some confusing differences in mate detail from that pic to #3. In some ways it looks like a taper mate, but the lower view of the part in #3 seems to show a key feature too.

Either that or I can't figure out what's going on (likely). It doesn't help that pic #5 shows it differently...

What's the machine and year it's from? Maybe that'll help in finding someone with a clue.

Machine is a 95 kao ming 2000sd. Cat50 spindle.

There are some differences in pic 3 and 5. Good catch! #3 is from the original manual, #5 is from a 2004 manual. Same spindle in each and I think the assembly is the same, but the newer manual has crisper lines and a cad drawing vs hand drawing.
Thanks

If you have no other options, I'd try something like a bearing separator between the large section of the cap and the housing (the drawings seem to show a decent gap there), and using a large gear puller or arbor press on the spindle end to "persuade" the parts to separate. Just be sure to have as much support as possible to prevent localized damage.

I can't be sure there's no mechanical interlock present, besides just the press taper fit. A bit scary when you don't know for sure. But given that assembly was likely though some spec for tightening up the nut, I'm not sure what else one can do...

It'll be pretty tight on that taper.

First try a slide hammer attached to the threaded holes on the face, if that fails combination of the slide hammer and a bearing heater.

gregormarwick said:

It'll be pretty tight on that taper.

First try a slide hammer attached to the threaded holes on the face, if that fails combination of the slide hammer and a bearing heater.

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If he does it that way he's beating the crap out of the bearings. Not that we know they're good, but I think it's best practice to work in a way that doesn't further damage them.

Milland said:

If he does it that way he's beating the crap out of the bearings. Not that we know they're good, but I think it's best practice to work in a way that doesn't further damage them.

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You'd have to be really rough with it to do any damage to the bearings. Like bubba rough.

Anyway, the only reason he could possibly have to remove that part of the assembly is to replace the bearings.

It popped right off. Very gratifying to hear that ping with very little pressure from the puller I setup and a tiny bit of heat. Glad I resisted the urge to beat on it last night and got M8 threaded rod this morning.


Sounds silly I know but I am keeping these bearings in a little longer if I can. In the middle of a job and if I can get a couple more weeks out them I will have more time. I'm seeing excessive heat on the tool holder taper. Nothing I can feel in the spindle though like roughness, and no abnormal tool finishes. I'm crossing my fingers they are just out of grease but largely undamaged. I am regreasing and reassembling. We'll see.
I did this with another machine a while ago and that seems to have put some life back into those bearings as well...

vmipacman said:

It popped right off. Very gratifying to hear that ping with very little pressure from the puller I setup and a tiny bit of heat. Glad I resisted the urge to beat on it last night and got M8 threaded rod this morning.
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Sounds silly I know but I am keeping these bearings in a little longer if I can. In the middle of a job and if I can get a couple more weeks out them I will have more time. I'm seeing excessive heat on the tool holder taper. Nothing I can feel in the spindle though like roughness, and no abnormal tool finishes. I'm crossing my fingers they are just out of grease but largely undamaged. I am regreasing and reassembling. We'll see.
I did this with another machine a while ago and that seems to have put some life back into those bearings as well...

Click to expand...

Heat is not really a typical symptom of worn spindle bearings IME.

Not sure of your experience level with this kind of thing, but be careful to put the correct volume of grease into each bearing or you will have heat issues...

Good stuff! Let us know how it runs when you reassemble it, and whether you see any change in running temps.

And that looks like a great way of pulling that cap off - well done!

Well shucks. New bearings it is. So after I got the bearing cartridge out of the housing I took it to an automotive engine shop near me. They are better setup for sliding the bearings off, working clean, and good mechanical practices. Its my compromise between sending to a dedicated spindle shop and completely DIY. They called that the two lower ones were toast. I asked about failure mode and he said they just looked dry, not a bunch of chips or debri in them. I had a bad feeling once I saw the discoloration of the lower bearing set after I got it out of the housing.
I have some new bearings ordered and hopefully going out today, next day shipping.

Engine shop said uppers were fine, lowers were practically locked up. This must have happened fairly quickly since I do a lot of toolchanges by hand and I noticed the heat pretty quick. I'm interested in seeing the bad ones firsthand because when the bearings (2 sets) were assembled, they spun really nice. I couldn't feel any resistance or notchiness. The upper set must have masked the bad set. Interesting imo.