What was this old 4 jaw?
I saw a peculiar 4 jaw "knuckle-buster" chuck at a sale yesterday. I don't have, and can't get, a picture, but I will try to describe it clearly.
It was about an 8 inch chuck, with jaws in very good shape, no wear or damaged faces. It was rather thinner than I am used to, about 2/3 as thick as my 6" Bison.
From outside, it didn't appear odd, jaws were normal except in two ways. Each jaw had two holes in it, similar to a normal two-piece jaw. And, only the hole nearer the center had a fastener in it. The others were plugged with cork. Each hole with the fastener had a round nut in it, one with slots for a spanner wrench, and the end of the stud the nut was on was visible.
I removed one spanner nut by hand, since they were loose. The stud was part of a nut that rode on the tightening screw, similar to a cross-slide nut. The jaw rode in a shallow slot in the body, with none of the normal T-slots. The only thing holding the jaw in/on the chuck was the tightening screw.
No part of the jaw, nor the spanner nut stud, etc had any T-slot or other retaining means except that the tightening screw went thru the stud/nut assembly.
I put it back together, replacing the jaw and nut, and tightening as much as possible with what tools were there. The jaw bound up pretty badly, almost as if you are supposed to be able to lock it by tightening the jaw with the spanner.
It had an adapter to a spindle size that I would expect to find on a woodworking lathe. But I could find no name on it.
I don't recall for sure if there was a thru-hole in the body. I think there was pne maybe 1 1/2 inch or so, but the adaptor covered it from behind in any case. The adaptor was obviously a much newer bolt-on piece, which was held on by what appeared to be flat-head slotted machine screws about 5/16 or 3/8" diameter.
Is that construction something common to woodworking type chucks?
I have a chuck with the jaws you were describing, but being really new to the trade I haven't really used it yet. The jaws just sit in shallow-ish grooves on the face and are held down just by nuts and bolts through to the back. They have a tightening bolt to clamp it onto the work, but it's not actually holding the jaw onto the chuck. Mine just threads onto my spindle. Don't know anything about it, the manager at my local HF threw it in free when I bought the lathe. I'll get some pics if I can.
If the HF guy "threw it in", it sounds like a new item, not old, which does suggest possibly the old one I saw was a woodworking type, still made. I know of no metalworking type made like that, it does not make sense, since with only one hold-down it can't be very stable. Then there is the question of the function of the other holes in the jaws.
Possibly the set of holes towards the outside of the jaws (jaws were on with highest step towards center, hold down screw in hole nearest to high step) was made to be used when the jaws were turned around so as to hold the OD of larger items (highest step towards OD)
Well he actually threw it in in kinda a weird way. I asked him if the lathe included a 4-jaw or not and he said no, but he had one that had been sitting around for 2 years that I could just have, he didn't know if it would fit or not (it did.) It seems to hold together really well, I mean the groove it sits in is very snug, won't wiggle at all, and the hold down pulls it in really well as far as I can tell. Again I haven't used it on metal and haven't ever seen how "normal" 4-jaw chucks work, so who knows.
Wow, found a pic really fast!
It looks almost exactly like that one, but it's about an 8 incher I think. Same style completely, I would bet that same company makes mine too. Do you think it would be too wimpy for metalworking?
(Ironically enough I actually did use it for some wood I needed drilling one time )
OK after a little more checking I now think it is indeed a wood-lathe chuck. But do you think I could get away with metal work on it?
Sounds/looks like the standard 4 jaw provided with the lathe by Grizzly and others. I’ve got an 8” that came with my Griz and it looks a lot like that.
Yah, they look close, but are different. That's a newer one.
Note jaws are only in a shallow slot, there is a hole to hold down the jaw etc.
The one I saw was similar but older. Flat-head mounting screws, knuckle-buster screwheads stuck out.
There were two holes in each jaw, and each had one more step than that.
But, I think it is a positive ID that it was a woodworking chuck. Thanks.