Smallest chuck with 3" bore

[Geof]

I am looking for a 3 jaw chuck with a 3" bore and the only size that seems to be available is 10" body, maximum speed around 2500 rpm, weight almost 60 lbs. Has anyone ever come across anything with less weight and a higher maximum speed?

[vladdy]

I looked around last fall for basically the same type, but didn't have much success..Logan have a couple that are lighter and rated for a higher maximum speed, but after checking prices I went with a Bison [3205?] 10" two piece flat back [got it at a local acklands store cheap, was a non returnable canceled order], added the adapter [around 200?] and had an old lathe useable again..

I had a Logan 10" power chuck on there before, but wanted an ordinary manual chuck instead...tossed the logan and the power head in the corner someplace...

enjoy.

[MarkT]

Your best bet may be to research precision work holding aftermarket suplliers and have be one custom made. This will be pricey, but if you have the need it may be worth it.

Best of Luck

MarkT.

[HuFlungDung]

You do have to allow some room inside the chuck for its inards, but there is nothing saying that you cannot bore the chuck body out a little bit. I needed 12" chucks with 4.125" bore in order to make use of my large bore lathe spindles, but I believe all I could get in the chuck I wanted was about 3.5". Well.....there I was, with a big bar in the lathe, but could not get it through the chuck......

I did open the chuck up first to see how much meat I had in there before I bored it. The scroll does locate on an inner boss near the chuck bore, so you do want to leave some significant material there. But in my situation, there was maybe 3/4" of wall thickness there, so going to 1/2" wall thickness did not concern me.

[Geof]

It is a while since I posed the original question.

I did find one made by SMW-AUTOBLOK which is just over 8" OD with a 3" bore.

So now I have a GT20-BB; a Big Bore GT 20 with a bar feeder that can take 2-3/4" round bar.

[ckirchen]

Originally Posted by Geof It is a while since I posed the original question. I did find one made by SMW-AUTOBLOK which is just over 8" OD with a 3" bore. So now I have a GT20-BB; a Big Bore GT 20 with a bar feeder that can take 2-3/4" round bar.

I have been thinking of doing the same to my GT20.

Can you post the part number from SMW? How much did you pay for it?

[Geof]

Part numbers??? They are going to take a few minutes to find and I am leaving very early tomorrow for a vacation until the end of the month; remind me early in November if I forget to post them.

Cost was about $6000 for the chuck and about $5000 for the hydraulic cylinder. We had a local shop make a custom drawtube out of DOM tube and also make the adapter for mounting the hydraulic cylinder and their parts cost about $2000.