Lathe chuck question

H

Half Nut

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Hello all, I have a craftsman commercial lathe, I picked up a 8 inch 4 jaw chuck for it, Question is it's about 50 lbs. Will that weight chuck damage the headstock bearings, The standard 4 jaw that came with the lathe is only about 12-15 pounds?

Thanks all.
John.
 
No, cutting forces far exceed 50 lbs.
 
This will be an interesting thread. I had a similar question a while back with regard to my lathe that has a 1 1/2"x 8 spindle with tapered bearings. My 4 jaw and my 3 jaw that came with the used lathe each weighed around 9 lbs and 7 lbs, respectively. The new chuck weights over 13 lbs and sticks out much further than the other 2.

Yours chuck is obviously significantly more weight. What size (type) spindle does your lathe have?
 
Hi it has the same as yours 1 1/2 x8 with Timken tapered roller bearings.

John.
 
What size chuck came with your lathe from the factory? That should be an indication if it's oversize or not. For what it's worth,
the FAQ on Logan's website advises against oversize chucks.
 
I am surprised that more members have not responded to this thread. Maybe this little bump will help.
 
I suspect the bearings will be fine as they are roughly the same kind of capacity as a car axle bearing - others here will know more. I would want to be very careful about applying any braking to this load, or running the lathe in reverse, with this mass spinning on a threaded spindle though.
 
Most of what I've read about larger chucks not being ideal has to do with the jaw opening be larger that they might strike the lathe bed.
My thoughts were about not having to clamp so dang hard to get a good grip on the material eventually causing damage to the jaws by over torqueing them. I'm thinking because the weight is applied radially, I think that's right, that it wouldn't be much of a concern with the Timkin roller bearings.
Still ,not so sure .

The lathe does not have any kind of breaking system, and having a screw on chuck I can't run it in reverse, bummer.
 
Still wondering if the 1 1/2-8 spindle can handle that kind of weight. Just seems like way too much weight to me. But, I am just a novice.
 
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