I have this nice 25 yr old Jet 1/2" drill press--has a nicely machined
Jacobs style chuck-(16mm)--a couple of years ago, it started slipping
while tightening it up. you get it fairly tight with the key,, and then
you can just keep on turning the key--w/o it getting any
tighter---although you have to turn the chuck key further than "normal"
to loosen the chuck.. Inspecting the innards doesn't reveal any obvious
defects..Do I need to clean one area & lube another???