I am having difficulty removing the Jacobs Multicraft 3/8" chuck from an old 7.2v Bosch drill/screwdriver, model SR7.2. Inside the chuck is a left-hand threaded countersunk machine screw 3/4" long, presumably down into the spindle. I have removed this and tried the usual tapping, pulling, even prising approaches without success. Anyone know (or maybe, as it's so old, that should be "remember") the secret please?
David

David Shorto, June 2008

Do not dismantle the drill, lock the shaft with an appropriate spanner by turning the chuck so that the end of the spanner rests on the bench at the same time as the body of the drill and will prevent the shaft turning as the chuck turns off. Place preferably an old key in the chuck and while holding the body of the drill strike it sharply (the key) in the direction of removal, make it a reasonably heavy blow to break the friction. Try to hit the handle end of the key so as to force it down into the chuck and also in the direction required.

Mike Blake, March 2009

Thanks John, appreciate your help

David Shorto, June 2008

Dave,

I think you have the secret. This is a normal thead (not a left hand one like the screw in the chuck). One thing is to make sure the torque is up as high as possible and that the drill is set in the correct way(Fwd/Rvs) so that tension is against your tap else the whole motor body just spins.

FYI on the Bosch web site they carry diagrams of every tool for the last 25 years os if in any doubt you should be able to go on there and look at the exploded view and (probably) download a handbook.

Having said all that I could not get the chuck off my old drill either but fortunately I could get to what I needed with the chuch still attached.

John, June 2008