Headstock Lock Stuck

[1957jimp]

When I turn the knob, only the front wedge moves. The back wedge does not move. Is that normal? Should I try and put it back on now to see if it locks?

The wedges are currently both at the outside of the tube.
Thanks, Jim

[DLB]

When I turn the knob, only the front wedge moves.
In relation to what?
The back wedge does not move. Is that normal?
No. Both should move toward the center of the threaded rod assuming they are not spinning in place. The way tubes normally prevent that spinning.
Should I try and put it back on now to see if it locks?
I would.
The wedges are currently both at the outside of the tube.
Way tube? If yes that should work.
Thanks, Jim

What did they look like when you first removed the headstock, and what have you changed? If there is interference again, try moving the whole wedge lock assembly in or out and see if it clears.
Only need to answer if you still have trouble: Fully unlocked, can you see threads between the front wedgelock and the locking handle?

- David

[1957jimp]

As suggested, I put the head stock back on. The lock mechanism at first seemed stuck. I twisted with more pressure and with a snap, it moved. The lock mechanism now works properly! Thanks much for the help! Jim

[JPG]

Glad to hear it behaves 'normally' for the present anyway.

Somethings need to be clarified as to how the lock is supposed to work.

The lock 'wing nut' when rotated rotates the threaded rod on which the wedges travel.

The wedges flat portion interferes with the way tube and prevents the wedges from rotating with the threaded rod.

The rear wedge has a 'right' hand thread, and the front wedge has a 'left' handed thread.

That results in the wedges moving in opposite direction when the wing nut is rotated.

A clockwise rotation of the wing nut/threaded rod results in the wedges moving closer to each other.

Observing only one move only implies the other has encountered some resistance.

When the two wedges are separated by the distance between the outer surface of the waytubes, clamping will commence. The wedges have an inclined plane that presses against the outer surface of the way tubes.

Rotating the wing nut counter clockwise will cause the wedges to move away from each other and thus release the locking force.

Verbose fer sure but think it should provide greater understanding.

[DLB]

JPG question - What does correctly adjusted look like to you on an assembled and mounted headstock? In the full unlocked position I want to see a few threads between the front wedge lock and the handle. In this case if I fully unlock it the wedges will stay put if I remove the headstock from the machine and still be the same when I put it back. The other case is the front wedgelock runs into the handle and that stops the turning, so the assembly is unlocked but the whole assembly can move in and out and will still turn if I take it off the tubes. I don't have the experience to know if this is all adjustment or if there are some other factors.

- David

[JPG]

JPG question - What does correctly adjusted look like to you on an assembled and mounted headstock? In the full unlocked position I want to see a few threads between the front wedge lock and the handle. In this case if I fully unlock it the wedges will stay put if I remove the headstock from the machine and still be the same when I put it back. The other case is the front wedgelock runs into the handle and that stops the turning, so the assembly is unlocked but the whole assembly can move in and out and will still turn if I take it off the tubes. I don't have the experience to know if this is all adjustment or if there are some other factors.

- David

Makes sense! I never considered that the few times I have removed/replaced a headstock, but always had cut off tubes or similar to position the wedges at reassembly. Gotta think about this - good suggestion!

I have always considered balanced travel on the rod a good goal, but this might require a tweak!