ID an unknown drill chuck.

[alfadan]

A local surplus place has a bunch of 3/4" drill chucks for $30. The only markings are the capacity and "japan".
The only thing I'm not familiar with is the mounting. There are two ears on the back and I think the hole is tapered but didn't have anything to measure it with. I didn't grab a pic but they look similar to this:
If I had to guess they came from the aircraft industry. Anybody know if these are a Jacobs taper?

 

[PBCampbell]

Most likely a JT3 mount with a chuck of that size. I have no idea what the purpose of those "ears" would be, hopefully someone with more knowledge will chime in, because I'm curious.

 

[neophyte]

Yukiwa Seiko, probably.
Yukiwa isn’t or at keast wasn’t the only Japanese manufacturer of drill chucks, but they seem to be the only widely available Japanese Manufacturer of drill chucks for the past couple decades or more.
They are, or at least were the manufacturer for the large majority of drill chucks Milwaukee used for the last two or three decades, and they manufacture chucks for Makita as well.

YUKIWA SEIKO USA INC. Drill Chucks, Tool Holder, Rotaly Tables, Spring Collets

www.yukiwa-usa.com

 

[alfadan]

They are, or at least were the manufacturer for the large majority of drill chucks Milwaukee used for the last two or three decades, and they manufacture chucks for Makita as well.

Interesting. I wonder if these are intended for a mag drill, maybe even Milwaukee since the only picture I can find says for Milwaukee drill.

 

[neophyte]

Maybe.
A couple pics of 3/4” Milwaukee drill chucks stolen from the internet.

 

[Rinspeed]

I was thinking mag drill as well with the tabs.

 

[alfadan]

Ok I went back and I found it was marked 3JT so I guess I just missed it. I got a couple, just need to get a couple arbors for my tailstock and mill.
30 bucks for a japanese 3/4" chuck ain't too bad!

 

[alfadan]

Yukiwa Seiko, probably.
Yukiwa isn’t or at keast wasn’t the only Japanese manufacturer of drill chucks, but they seem to be the only widely available Japanese Manufacturer of drill chucks for the past couple decades or more.
They are, or at least were the manufacturer for the large majority of drill chucks Milwaukee used for the last two or three decades, and they manufacture chucks for Makita as well.

YUKIWA SEIKO USA INC. Drill Chucks, Tool Holder, Rotaly Tables, Spring Collets

www.yukiwa-usa.com

You wouldn't by chance have disassembled one of these chucks before? One of the two has some very tight spots and might have to see whats going on inside it. I'm familiar with a Jacobs plain bearing.

 

[neophyte]

You wouldn't by chance have disassembled one of these chucks before? One of the two has some very tight spots and might have to see whats going on inside it. I'm familiar with a Jacobs plain bearing.

Never taken one apart.
I presume the basic keyed Yukiwa chucks are clones of Jacobs, but am not certain.

 

[rustyzman]

I have a large Jacobs chuck with those same ear cutouts.
Way back when I got it ~20-25 years ago, the guy at J&L Industrial had a name for that style (when I brought it in to get an arbor for it) and said the one I had was a special for GM. According to him they specified that style for their use. Who knows if he was correct or not. I'll have to dig it out and see I can jog my memory on what he called it.

 

[RaisedByWolves]

Interesting. I wonder if these are intended for a mag drill, maybe even Milwaukee since the only picture I can find says for Milwaukee drill.

Yes, mag drill chuck.

 

[alfadan]

Thanks everyone. I ordered a couple of arbors. The ears may interfere with the R8 arbor so may have to cut the ears off.

One was binding but a couple whacks upward on the chuck body freed it up nice; probably got dropped at some point.