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Bridgeport chuck/ shank suggestions


Dec 22, 2018
Have a bridgeport series 1 model 2j that I'd like to get running. It's sat in our shop for years after it was given to us. We're not a machine shop so never spent the time to learn it or get it set up, plus it needs a little work as some of the levers are missing and replaced with something fabricobbled that isnt really correct. It would give us a kick ass drill press...If I had a good chuck. My fear is shearing the keyway on the r8 as some of our guys should work for underwriters labs. Can anyone help me out with a set up? Most all of our stuff would be under 5/8"
Keep a supply of keys on hand and tell the operators "You broke it, you fix it." From what I saw in our shop, damage was a sheared key, not a damaged collet. One problem you may run into is operator misses or ignores a sheared key and continue running. When the tool slips in the collet, they crank the drawbar tighter and may end up breaking it, or scoring the spindle bore and collet.
I've never seen a key sheared by a drill unless a wreck was involved. Sounds like that might be the issue for you.

Slitting saws or circular milling cutters jamming up is the way I've seen most sheared. Sometimes the key will cut a notch in the collet keyseat and that is a real pain.

If your guys are gonna wreck stuff you'll probably shear some keys. Get a good R8 shank and an old good condition jacobs ball bearing chuck. New jacobs chucks and amazon shanks are well crap. Accupro brand is also crap. DAMHIK.
Remove the key. It is only useful for keeping the collet from spinning while tightening, and is not necessary for that. The taper is what drives the collet/tool once tightened. A damaged key can mean a serious headache, especially if the collet/tool can't be removed.
My 1974 Rockwell mill that I bought new has an R8 spindle and was built without a collet key. I have never had any trouble with slipping tooling because I properly tighten the draw bar. The taper will hold against any reasonable torque load if the draw bar is tight. I have never had a wreck or tried to use a huge shell mill, so never had a problem with slipping.

On a Bridgeport, it would probably be a good idea, as others said, to just remove the key before someone does something foolish and causes damage.

One caution: Using R8 tooling with no collet key in the spindle only works if the threads on the tooling and draw bar are in good shape. Tooling with damaged threads should be repaired or scrapped immediately.

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Many people remove the key since it is not a shear key. It is not designed to transmit any real torque. It's only purpose is to hold the shank from turning in the spindle as the drawbar is tightened.
Bill D
We have had a number of R8 mills in the shop that is to say different manufacturers Bridgeport, Clausing-Kondia, a number of which have left the building as surplus.
We never used the keys, never was a problem.