Need Help to disassemble 10 inch Bergmans 4 Jaw Chuck

[cathead]

It looks like the thread part of the chuck is held in with a cylindrical part inserted from the back of
the chuck. I removed the jaw and apparently the cylinder is press fitted in from the back. I tried
a little heat and a punch and hammer but there isn't much room to really get at it so it isn't moving.
Apparently one needs to make a little tool to fit and press it out. The jaw binds somewhat and
there is a lot of front-back slop which is the reason for the disassembly. I'm guessing the
threaded part is bent a little. It's a nice chuck made in Sweden so hoping to make some repairs
and put it to use. Any ideas out there??? The jaw is off but not the retaining cylinder holding the
acme looking threads.

 

[flutedchamber]

Aren't there 4 socket head capscrews threaded in from the face of the chuck?

 

[xalky]

That locking cylinder should be a tight fit but not a press fit. Try spraying some good penetrating oil in there. Let it sit for a day or so. You can apply heat around the cylinder but not on the cylinder, which will expand it, making it worse. After heating it you, can attempt to cool just the cylinder part with some of that "dust off" computer duster in a can. It comes out cold. Then try pounding it out. Be careful to not damage it.

 

[cathead]

The cylinder is tapered so not a press fit as it looks. After milling out a properly shaped 2 pronged punch,
one whack and it popped out. It turns out that the screw was bent slightly so chucked it up in the
lathe and used a lead hammer and a dial indicator to true it up. Also, the end play was remedied with
a shim and after reassembly, I now find it ready for service. I have a larger Bison Chuck that looks to
be made the same way. The rear of the chuck has a taper that goes from at least 2 to about 3 inches
with a depth of a couple inches. Also, there is a key way about 3/8 inch wide in the taper and some coarse
threads on a ring on the outside. I have no idea what lathe it fits, maybe someone on here will know. At
this point, I am thinking of either machining an adapter or using 123 blocks under it and clamping the
chuck to a rotary table. The other alternatives are to machine off the threads I suppose or maybe
use it as trading stock. It's a Swedish chuck so maybe it fits some European lathe. Included are
2 photos, one of the front with the punch in view(also home make key), and the rear shot showing
the taper and key belonging to the unknown to me lathe. Thanks to all for the interest and responses.

 

[Bartonius]

Looks like an L Taper.


My Logan has L00

 

[cathead]

Thanks, Bartonious! It appears to be a L00 style. It's good to know what it will fit.

 

[flutedchamber]

OK, now I understand what part of the chuck you were talking about. I made the same tool you did, but out of brass. Some penetrating oil and sharp taps and the keepers will come straight out.