Quote from: "1FATGMC"This past year I got a keyless chuck for my mill/drill. I love it and would like to also get one for the tailstock of my lathe and for the new mill I just ordered. The one thing that has been a problem with the new chuck and the old chuck is that occasionally when drilling with a bit in the 3/4 inch to 1 inch size the bit will grab the metal and the chuck will spin on the R8 tapered adapter.any drill over 1/2" should be a taper drill which fits your Drill head taper and tail stock etc. Using turned down drill shanks is asking for trouble with inaccurate work.
I can get the new keyless chucks with either 6JT or 33JT mounts and I can get both a R8 to 6JT or R8 to 33JT adapter for the mill and a 3MT to 6JT or 3MT to 33JT for the lathe tailstock. Is one of these tapers less prone to slipping than the other??
Thanks,
Sum
Buy quality taper shank drills which fit your tapers. mark them with blue and check the taper is correct before use, If there are high spots etc use a fine lapping paste to to get the taper to fit correctly.
A correctly fitting taper should NEVER have to be hammered home!.
A drill should be just pushed into the taper and must be capable of sitting by itself.
Any normal drill made in the last 180 years will have a slot to insert your taper drift to release the drill and, to release it from the tail stock ,this should be designed to pop it out when the screw is returned back fully.
Keyless chucks are for cheap quick work,something you should avoid if you want to make quality stuff with your machine.
if I had been caught wacking a machine with a hammer when I was serving my Apprenticeship ,I would have had the hammer used on me...