I think the lock up is solid. The jaw do a great job of holding all hooks. I just put a #2 salmon hook in the jaws and tugged on the eye of the hook, the hook shaft bent but no slippage at all. This vise is the Cadillac of all vises, I just never tie fiys anymore so its a waste to hold on to it. I would love to see this vise go to a avid fly fisher who is going to run it hard.