Need help with Sjogren collet chuck

I acquired this Sjogren collet chuck, model 2A-D3, and took it apart while looking into some runout issues. The first photo shows the front half of the chuck with the rear (spindle side) half in the background. The bore of the center gear is threaded to receive the 2J collet. As the center gear rotates and pulls the collet in, the opposite face of the center gear hub, as I surmise, is supposed to contact a thrust washer (tinted blue in the second photo) which in turn contacts a thrust bearing. However, in my unit the back end of the hardened spindle sleeve (tinted in purple) projects farther into the chuck body than the thrust washer/thrust bearing assembly by about .020" (1/2 mm), so that the hub of the center gear rubs against the narrow back face of the spindle sleeve instead, rendering the thrust bearing unused. It appears to me that there is a missing washer or spacer that fits between the center gear and the thrust washer. It's odd, since a thicker thrust washer would obviate the need for an additional part. It makes me think there's something missing in my understanding of how this contraption works. It's hard to find accurate info on this as there seems to be a large number of models of this chuck, with the innards arranged somewhat differently for each model. Any definitive advice on this would be much appreciated.

Mike

Maybe this will help.
https://www.shophardinge.com/assets/docs/B123.pdf

JB Bergman

JB Bergman said:

Maybe this will help.
https://www.shophardinge.com/assets/docs/B123.pdf

JB Bergman

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Thanks, I've seen that cut-away view before, and it doesn't seem to show an extra spacer, so I'm puzzled.

Mike

I have a 2A-D3 disassembled and setting on the workbench at home. I'll try and remember to have a look at it tonight. Feel free to PM me as a reminder if I forget and don't followup and you are still looking for an answer.

Complete photo breakdown of a 5C D1-6 Sjogren (for comparison with the 2A-D3) available at this PM post.

I can't tell from the 2A-D3 photos if the center gear is intended to take felt washer rings, which would serve the purpose of spacers. See the 5C D-16 photos. I see grooves in the right place in the 2A center gear, but can't tell if they are deep enough.

sfriedberg said:

Complete photo breakdown of a 5C D1-6 Sjogren (for comparison with the 2A-D3) available at this PM post.

I can't tell from the 2A-D3 photos if the center gear is intended to take felt washer rings, which would serve the purpose of spacers. See the 5C D-16 photos. I see grooves in the right place in the 2A center gear, but can't tell if they are deep enough.

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Yes, thanks, I saw those pics and studied them closely. The center gear for that chuck has deeper grooves than mine on both faces, plus the hub has two different diameters (I would guess the larger diameter contacts the thrust bearing), whereas mine has only one. On mine there is a deeper groove in the rear plate (you can see it in the upper left of the first photo) that carries a felt ring that "seals" against the center gear, but there is no trace of felt to be seen on the opposite side of the gear. Besides, I don't think a compressible felt washer is a good candidate for taking up thrust loads.

Mike

morsetaper2 said:

I have a 2A-D3 disassembled and setting on the workbench at home. I'll try and remember to have a look at it tonight. Feel free to PM me as a reminder if I forget and don't followup and you are still looking for an answer.

Click to expand...

Thanks very much, perhaps that can clear up the mystery.

--Mike

Mike, On mine, when I install the thrust bearing, then the thrust washer, the thrust washer sits proud (up higher) than the back end of the collet sleeve by about .013-.015 or so. Measured w/ caliper depth rod, which is not very precise, hence the range of the dimension. But I can verify that dim by feel w/ my finger.

The center gear def rides on the thrust bearing washer, not the back of the collet sleeve. I can feel it. And when I take the thrust bearing & washer out, and put the center gear back in (w/o bearing & washer), so it sits on the back of the collet sleeve, that center gear sits down lower into the "nose housing".

My thrust washer is quite thick. So maybe that might be the issue, if yours is thinner.

Thrust bearing ball diam = .156
Thrust washer thick = .172
Center gear OA thk = .625

And two pics of center gear installed. One w/ thrust bearing & washer in place, the other w/o, showing distance gear stands proud from back face of nose piece.

morsetaper2 said:

Mike, On mine, when I install the thrust bearing, then the thrust washer, the thrust washer sits proud (up higher) than the back end of the collet sleeve by about .013-.015 or so. Measured w/ caliper depth rod, which is not very precise, hence the range of the dimension. But I can verify that dim by feel w/ my finger.

The center gear def rides on the thrust bearing washer, not the back of the collet sleeve. I can feel it. And when I take the thrust bearing & washer out, and put the center gear back in (w/o bearing & washer), so it sits on the back of the collet sleeve, that center gear sits down lower into the "nose housing".

I'll add some pictures of my parts in another post. which may provide some clues. My thrust washer is quite thick. So maybe that might be the issue, if yours is thinner.

Thrust bearing ball diam = .156
Thrust washer thick = .172

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Thanks so much, this is very valuable information which tells me something is amiss with my chuck. My thrust washer thickness and bearing ball diameter are the same as yours, but the thrust washer is not even flush with the back end of the collet sleeve--as I mentioned earlier, it's about .020" short. Another curious thing (and I would very much like to know if yours is the same), is that the nose bore diameter is 2.315", but the thrust washer is only 2.297" and the gear hub is only 2.294", so that they both rattle around in the bore, and this of course affects the engagement of the center gear with the pinion gears. This kind of slop seems to me to be way beyond any normal wear and I can't imagine this is by design. Looking forward to hearing about any additional comments, measurements, and photos you may be kind enough to send my way.

Mike

Added some photos and ctr gear thickness to post #8. One thing, on mine, looks like there is a thrust washer held captive in the nose. But hard to tell what it is down in that recess.

I'll have another look at your new questions tomorrow when I'm in the shop. -ML

Mikel Levy said:

Another curious thing (and I would very much like to know if yours is the same), is that the nose bore diameter is 2.315

the thrust washer is only 2.297"

and the gear hub is only 2.294"

Mike

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The nose bore OD (where thrust washer & bearing go into, is 2.315 on mine, just as yours.

My thrust washer OD is 2.291 (vs yours @2.297). My thrust washer has just a couple thou clearance on its ID to the OD of collet sleeve. The OD of collet sleeve keeps it in place.

The boss on my gear (see picture) is 2.310 (vs yours @ 2.294)

Also, another picture, which sort of shows what looks like a "captive" thrust washer down in the cavity.

Well I got to thinking about that "captive" thrust washer. And I blasted some compressed air to the edge and that washer is not captive. Just held in place by years of congealed grease. It loosened and came out. It has the same exact dims as the other thrust washer on opp side of bearing. So you might try and remove the lower thrust washer and measure it. You could shim behind it to get everything sitting "proud" of the collet sleeve?

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And a question about your first photo. You have an additional dowel pin that I don't have. I have two dowel pins, 180* opposed, that are the axis of rotation for the two small duplex gears, like yours. However, you have a third dowel pin, on the collet nose side, that I don't have on my chuck.

morsetaper2 said:

Well I got to thinking about that "captive" thrust washer. And I blasted some compressed air to the edge and that washer is not captive. Just held in place by years of congealed grease. It loosened and came out. It has the same exact dims as the other thrust washer on opp side of bearing. So you might try and remove the lower thrust washer and measure it. You could shim behind it to get everything sitting "proud" of the collet sleeve?

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And a question about your first photo. You have an additional dowel pin that I don't have. I have two dowel pins, 180* opposed, that are the axis of rotation for the two small duplex gears, like yours. However, you have a third dowel pin, on the collet nose side, that I don't have on my chuck.

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To answer your question, I believe that extra pin is to register the two chuck halves so that they cannot be assembled in the incorrect orientation.

Neat trick getting out that washer with compressed air. Didn't work for me, so I squirted some penetrating oil in there and let it sit overnight. Next morning the old grease was dissolved sufficiently for the washer to come loose. I fabricated a .026" thickness shim washer and placed it in the bore before replacing the original thrust washer. This let the hub of the center gear clear the rear of the collet sleeve by about .009". So now the center gear properly rides on the thrust bearing, but not all is well. The center gear now rises above the inner face of the chuck half by .144". The recess to receive it in the inner face of the mating chuck half is only .134" deep, Therefore the center gear now prevents the two inner chuck faces from contacting when the chuck is reassembled. If you do the math, the only practical solutions require either machining off some material from the face of the center gear hub, or making the recess deeper. Not sure I can take a skim cut on that gear hub because the threaded insert is probably hardened. It's pretty clear that this chuck could never have functioned properly with its current parts.

There are quite a few things that are curious about this particular chuck. As noted above, if it came from the factory the way it is now, it was defective from the get-go. Unlike my seven other pieces of D1-3 tooling, this one would not seat properly on the lathe spindle. After carefully dressing the D1-3 taper on the chuck back via a tedious iterative process and achieving a proper and accurate fit to the spindle, the collet taper exhibits .003" TIR, which is not good. Another weird thing, if you look at the first attached photo, is that the face of the center gear adjacent to the hub shows tool marks that suggest that it was milled on a rotary table setup--seems rather odd. And the outside of the chuck nose (see second photo) has the appearance of having been turned down--what possible purpose could that serve? And that lubrication port looks more like a ball oiler than a grease fitting. Even if I finally manage to get the moving parts working properly, I have the .003" runout to contend with, and the last thing I want to do is to grind that collet taper.

It's all very strange, and I would be embarrassed to tell you how much time I have spent fooling with this piece of crap.

Mike

Mikel Levy said:

After carefully dressing the D1-3 taper on the chuck back via a tedious iterative process and achieving a proper and accurate fit to the spindle, the collet taper exhibits .003" TIR, which is not good. Another weird thing, if you look at the first attached photo, is that the face of the center gear adjacent to the hub shows tool marks that suggest that it was milled on a rotary table setup--seems rather odd. And the outside of the chuck nose (see second photo) has the appearance of having been turned down--what possible purpose could that serve? And that lubrication port looks more like a ball oiler than a grease fitting. Even if I finally manage to get the moving parts working properly, I have the .003" runout to contend with, and the last thing I want to do is to grind that collet taper.

Click to expand...

FWIW I have a 5C on a D1-6 mount that i couldn't get to run true, it ran out ~.0015 no matter what or how I stoned the surfaces or reassembled it. I finally hard turned the taper ID with CBN with the lathe compound and it goes on at .000 TIR easily.
I don't remember anything unusual about the innards, sorry I can't help there.

Mud said:

FWIW I have a 5C on a D1-6 mount that i couldn't get to run true, it ran out ~.0015 no matter what or how I stoned the surfaces or reassembled it. I finally hard turned the taper ID with CBN with the lathe compound and it goes on at .000 TIR easily.
I don't remember anything unusual about the innards, sorry I can't help there.

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Interesting, and thanks for the input. I don't have any CBN inserts, and they look to be pretty expensive, but it's good to know that possibility exists.

Mike

OK, makes sense about that pin. As mine can assemble either way.

I'll put some pictures of my innards up for you to compare. I see what looks like a set screw or pin in your center gear. Mine does not have that, nor those "ro-tab looking" milling marks. Of course yours could be older than mine and Hardinge/Sjogren didn't have their process down. Or perhaps someone has been in there monkeying around, switching parts out, who knows.

My 2A-D3 no longer has a D1-3 back. It was machined off. So I bought it to mount to a back plate for my South Bend 10" lathe. Haven't made that back plate yet as this project went on hold for other things.

Mikel Levy said:

Interesting, and thanks for the input. I don't have any CBN inserts, and they look to be pretty expensive, but it's good to know that possibility exists.

Mike

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There's lots of cheap CBN on ebay, you can get TPG 322 inserts for under $20. My favorite all purpose grade is Sumitomo BN200 if you can find that, but just about anything will work for that job.

morsetaper2 said:

...Or perhaps someone has been in there monkeying around, switching parts out, who knows.

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Someone has definitely been in there before me--when I opened it up, the timing marks on the pinion gears were not aligned to the marks on the center gear (as an aside, the gears are radially symmetrical, so why should it matter?).

Mike