Help! My Bessey F clamp got stuck

[Susumu Mori]

On the other day, I was in a woodworking shop and saw a gentleman brought a Bessey F clamp (K body) which was closed shut completely. I didn't pay much attention but I did mentioned to the store manager, "oh, even Bessey sometimes has a problem." I'm not sure if he could solve the problem but when I left the shop, I saw a couple of shop people were still working on it.

Now, a week later, I put one of my Bessey clamps against a wall and the jaw dropped by the gravity and "bang", it completely closed and no matter what I do, it doesn't move at all. Now I know how he got that problem. I think this thing costed my about $50!

I'm wondering if this is what F clamps do or a defect affecting only a small number of the clamps. I would really appreciate if any of you know how to open it.....

[George Bokros]

Make sure the handle is screwed to the fully released position and wiggle the knob toward and away from the bar.

[Sam Murdoch]

This is more likely NOT A DEFECT but caused by the jaw being shut tight without any wiggle room on the threads. Always need to back off the jaws a bit by unscrewing 2 or 3 threads (at the least). I find this to be the case with any kind of clamp that slides on a bar. What George said is your best solution to open - maybe also whack the other end against the floor as you wiggle the head.

[Jim Matthews]

There is a pawl, at the back that engages the ridged bar.

Drive a wedge into the top of the pawl, where it
is stuck in place. Rap the bar on the floor (preferably concrete)
to get gravity working in your favor.

[Susumu Mori]

Thank you all.
I tried to what you suggested and became more familiar with the structure. Then it came to my mind; maybe I could just slide out the red protective pieces of the plastic of the jaws. I slid them out (of course they were tight but eventually came out) and the jaws got released from the stuck position; problem solved.

Thank you for your kindness to offer your solutions anyway!

[Judson Green]

Isn't there a set screw like thing that engages the micro teeth on the bar? You could perhaps loosen/remove that.

[Rick Moyer]

That almost happened to me once, so now I try to always have a few threads showing beyond the handle jaw piece so I can back the jaw up.

[glenn bradley]

Glad you got it fixed. As others have said, the screw at maximum on this type of gripping system can get stuck if jammed into position (sliding handle section due to gravity is a familiar culprit). Clamps with looser (some say sloppy) fitting jaw systems are not as prone since you can jiggle things enough to get them to let go. This doesn't have to happen often to get one to start confirming that there is some adjustment room left at the screw. DAMHIKT.

[Susumu Mori]

Glenn, that makes perfect sense.
Now I'm much more careful about the position of the screw and gravity!
It is a nice learning curve to properly use well-made tools.

[John Coloccia]

I grab the clamp by the jaws and bang the bar straight down on the floor. It usually flies right open. Obviously though, easiest is to simply never screw the clamp all the way out. :)

[Randy Tucker]

Thank you all.
I tried to what you suggested and became more familiar with the structure. Then it came to my mind; maybe I could just slide out the red protective pieces of the plastic of the jaws. I slid them out (of course they were tight but eventually came out) and the jaws got released from the stuck position; problem solved!

Kudos to you! Thanks for the solution to my stuck clamp.