There is an Ausonia 1-13 mm keyless chuck here on a
13 mm drill press. The chuck is roughly 30 years of age and has not received heavy use. When the power is switched off and the spindle winds down, the chuck frequently loosens enough to allow the drill to fly out. As the chuck is turned to tighten or loosen, it is free of any friction or roughness.I've just dismantled, cleaned out a few chips and reassembled with fresh grease. This had no effect on the loosening behaviour.
Seems that the problem might be just a geometrical feature of the design, such as the helix angle, which is problematic only after the surfaces are worn smooth from use.
Is there any solution other than buying a reverse-locking chuck?
If replacement is the best solution, I am interested in advice about brands. These are approximate local prices in Canadian dollars.
Rohm Spiro Heavy Duty 1/32 - 1/2" $210. Jacobs High Torque/High Precision .039" - 1/2" $325. Albrecht Classic 1/32" - 1/2" $345.
Thanks, Peter E.