I have tinkered with making a couple vacuum chucks, but so far have not found them to hold well enough in their current configuration and with my shop vac. I have not yet set up the lamp all thread and actually put a vacuum on the chucks when on the lathe. Trying them directly on the shop vac hose has not made the set up look promising enough for me to proceed as is.

They hold fairly loosely and do not seem like they will stay centered well. I tend to think maybe the problem is the poor vacuum of the shop vac. Am I kidding myself on that? I am willing to buy a real vacuum pump or improvise one from a refrigerator compressor, but would hate to go through the trouble or expense to have the chucks not work well any way.

It seems like they would work fine as long as I used a live center along with them, but at that point i don't see much or any advantage over a jam chuck.

Comments or suggestions?