Shopsmith Forums

Hi! Mark V 520 owner here, with a frozen headstock lock.

I need to replace the left wedge lock (the one on the front side) on my headstock lock. The right/rear lock turns fine on the screw (is that what it's called?), but the left one is frozen in place. I have removed the motor pan and I can access the headstock lock assembly, but I can't seem to figure out how to remove it. I've removed the pin to the lock handle, but I'm not sure how to separate that from the screw. I have a replacement handle, pin, screw, and left wedge lock, but looking at the new part doesn't offer much help: the handle came attached to the screw, and it doesn't look like it's meant to come off. I can't figure out what to do here.

The wingnut may require significant torque to remove it(left handed thread, burrs from drilling pin hole)

The wing nut needs to be removed from the new threaded rod to install the front wedge.

It may be necessary to cut the threaded rod to remove it with a wedge jammed on it.

Holding the threaded rod at the non-threaded center with a vice grip may help removal.

The handle is threaded on, with left hand threads, so turn the handle the wrong way while holding the screw with vice grips in the middle. Use some penetrating oil if it doesn't budge. The wedge locks are threaded on also, often corroded, and some penetrating oil will help the wedges turn. The screw is double-ended, meaning the threads run opposite directions. Turn the wedge locks toward the center of the screw until you can work the assembly loose from the casing.