Just a 3-jaw Cushman on my 10EE, plenty old but in much better than usual condition. Well, "better" except someone replaced the outer jaws with new ones.
Chuck holds/runs nice and straight, chuck itself showing very little runout, but holds stock consistently .010 eccentric.
I know I shouldn't expect much from a 3-jaw. It just becomes annoying when I flip a part and the chuck repeats that .010 runout. (Again, I know it is a 3 jaw; these aren't precision parts).
At the end of a long Saturday I decided remove & clean jaws, clean scroll and chuck jaw slots, reassemble and measure TIR from a straight shaft chucked. No improvement.
Then I started swapping jaws, keeping track of swaps as I progressed. First switch, no improvement.
Second swap gave .008 repeatably. Third swap, .006 and fourth stayed the same. By this time I was sure that was max improvement.
Went ahead with 5th possible placement of jaws and got .002 repeatable! 6th position got me a consistent .001-.0015! What a pleasant way to end the day.i was absolutely sure the moving of replacement jaws would make no difference.
Now I need to mark each jaw with new numbers, and cross out the original 1,2 and 3 numbers the jaws came with. I guess the previous owner figured installing the numbered jaws in their respective locations was the only right way to install them.
I'm happy with this outcome! No need to buy a better chuck!
Chuck holds/runs nice and straight, chuck itself showing very little runout, but holds stock consistently .010 eccentric.
I know I shouldn't expect much from a 3-jaw. It just becomes annoying when I flip a part and the chuck repeats that .010 runout. (Again, I know it is a 3 jaw; these aren't precision parts).
At the end of a long Saturday I decided remove & clean jaws, clean scroll and chuck jaw slots, reassemble and measure TIR from a straight shaft chucked. No improvement.
Then I started swapping jaws, keeping track of swaps as I progressed. First switch, no improvement.
Second swap gave .008 repeatably. Third swap, .006 and fourth stayed the same. By this time I was sure that was max improvement.
Went ahead with 5th possible placement of jaws and got .002 repeatable! 6th position got me a consistent .001-.0015! What a pleasant way to end the day.i was absolutely sure the moving of replacement jaws would make no difference.
Now I need to mark each jaw with new numbers, and cross out the original 1,2 and 3 numbers the jaws came with. I guess the previous owner figured installing the numbered jaws in their respective locations was the only right way to install them.
I'm happy with this outcome! No need to buy a better chuck!