Anyone know how to remove chuck in Delta mortiser?

[Kevin Perez]

I have a Delta 14-650 hollow chisel mortiser that has quite a bit of runout in the jaws (i.e., using different bits to measure it), but nearly none in the shaft or chuck body. I’d like to remove it to investigate but can’t figure out how. The manual says to put a screwdriver in the top part of the shaft above the motor, and to use the chuck key to unscrew it. But I’m not sure what the last part means—to use the key to hold the chuck so the shaft can be unscrewed, or twist the key as if you are loosening the jaws until the chuck body unscrews. I’ve tried each gently with no luck, and don’t want to break anything. Any ideas?

[Bill Dufour]

Sounds like it is screwed onto the arbor like many hand drills. Put in the biggest allen wrench the chuck can hold. then wack the arm of the allen wrench to unscrew the chuck. Hold the arbor with the screwdriver so it does not turn.
Bill D

[Kevin Perez]

Thanks Bill, I’ll give that a shot.

[Tom M King]

If a chuck screws off, doesn't it have a screw inside for security? If so, that has to come out first. Check that before doing the big allen wrench thing. Double check about whether that inside screw is left handed threads.

[Kevin Perez]

Thanks all. I got the chuck off using an impact driver with a hex bit in the jaws and a screwdriver on the motor shaft. I couldn’t get the threaded spacer off, so I just cut down my mortising bit. Once I cleaned and lubed the chuck, the runout is only about .005-.007, which works just fine.