MON Sjogren 2J Collet Speed Chuck Tightening

J

JFL4066

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Hi all,

I have a 10EE Monarch square dial machine with the Sjogren 2J Speed Chuck. It has the aluminum finger grip hand wheel. My problem is I can never get the collet tight enough using the hand wheel. All of the collets and chuck are in excellent condition. I'm usually chucking round bar from 3/8" to 1" and they will move inward when taking a face cut and rotate slightly when taking a regular cut. I have tightened an empty collet to be sure it does pull in and reduce in size. What else can I do?
 
Spring collets like R8. 5C, and 2J only really clamp well on stock that is within a few thousandths of the nominal size, with anything else, the work is being held by a cone shape instead of a cylindrical parallel bore. The cone only clamps at a small ring along the length of the collet, and the work can also flex easily away from the axis. Are you having this problem with multiple sizes of nominal size stock, using collets the same size as the stock?
 
Hi Bob,
Yes. Multiple sizes, 3/8, 1/2, 3/4, etc. Nominal stock is within a thou. and clean. No oil or rust. I use the 3/4" collet with the 3/4" nominal bar stock.
 
Is there a way you can put more torque on the wheel?
Maybe a strap wrench?
With my Kurt 8" vise I sometimes use a 2" by 18:" pipe to get extra leverage,especially for pressing.
 
If I remember right, that chuck is supposed to have a hammer feature on it. In other words, the wheel is free in reverse so you can snap it forward to hammer it shut. It just may need a cleaning.
 
I've never had a problem getting my 2J chuck to tighten. No need for a strap wrench or anything else. There's probably something wrong with your chuck. They're not very complicated internally.

Have a look at this YouTube series: James Kilroy - Hardinge Sjogren chuck repair. He repairs a chuck with a bad internal thread by pressing in a bushing and threading it. He mentions that the idler gears need to be properly timed for the chuck to work, but doesn't show how to reassemble it.

This video shows disassembly, greasing and reassembling the chuck: Hardinge Sjogren Collet Chuck Cleaning

Here's a link to the parts diagrams for the various models: Sjogren Speed Chucks Parts Lists
 
Some of that type chuck have a rubber grips molded on over the metal, which gives a better grip. If the machine has a foot brake or a spindle lock, that could also give more tightening strength. Wiping any oil off the chuck and hands before trying to torque it would probably help as well. I sold one of those chucks once, and the new owner loves it. I watched him tighten it without any theatrics and it worked fine. It may need a disassembly, careful inspection, and cleanup and fixing/replacing anything not in good shape.
 
Thanks for everyone's input! I'm going to take it apart and inspect. I agree, it's designed to use hand tightening and using tools is just not right. My Monarch was built in 1953 and the chuck came with it, so it probably needs a little TLC. I'll post my findings for everyone's info. An additional thanks to Cal for all of the info links.
 
If it's original to the machine, the machine's serial number should be stamped on the back of the chuck.
 
So, I took the chuck apart and cleaned it. Grease was nice and clean - no debris. Felt seals were intact and very good condition. No excessive wear on spur gears, ring gear, gear studs, collet threads, etc. No burrs or galling. Lightly greased and reassembled. Motion is nice and smooth. The only thing I did notice was grease on the chuck threads, which I cleaned off and put some #2 mobile Vactra oil on. I also checked chuck collet taper and locating pin. Both were in excellent condition. I reinstalled the chuck on the lathe and chucked up 5/8" bar stock and 1 3/8" bar stock. The only movement I got was when I was center drilling the 5/8". Moved about 10 thou. I retightened the chuck and it helped. I'm going to buy some 2 part urethane grip coating and apply it to the aluminum hand wheel and see if it improves my grip. It seems the last couple of degrees of rotation is what matters.

Cal - thx for the tip. I'll check it when I'm back in the shop.
 
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