I’ve acquired a used Nova chuck and four sets of jaws. The Allen screws holding the jaws were really tough to back out. An Allen wrench didn’t come with the chuck so I’m using one from a metric set that I have. I had to clamp a vise-grip on to the wrench in order to break them loose. Just how tight are these screws supposed to be? Do I need to invest in a special wrench? Thanks.

Thanks Rick, for the help. Is it your experience that the screws tighten or might back out during turning? As I am new, I'm still a wee bit skitish of something comming loose.

Hi:
I use a plastic T handled allen wrench for mine.  I would think a regular allen wrench in that size would be pretty small and not give a lot of leverage.  The countersink that the screw head sits in seems to be a really good fit which generates a lot of friction to resist loosening the screw.  I probably do tend to overtighten them, just like everything else... 

Take care
Bob

It is well worth the few extra bucks to get a quality set. The steel/heat treat in some of them is not up to the job.

i also have a nova chuck. mine came used with two regular allen wrenches. the first time i took them out, they were in very tight, when i put them back in, i just snugged em up, and i had no problems.. i change jaws fairly often, and don't have any problems.


three of my four sets of jaws are made to accept both screws. so if one starts to back out, it will probably feel funny, or throw the workpiece out of center just a touch or something.


i am more scared of the wood coming out of the nova than the jaws coming off.

I have the nova, just hand tighten. Directions say do not overtighten. I have never had a problem with them loosening.

Make sure the bottoms of the jaws and the groove is clean though, any dirt will leave some wobble in the jaw.

Don't think they will come loose unless you do a lot of reverse turning since the lathe turns left and the screws turn right to tighten.

And, I think there's the fact that the jaws are very soft steel (so they don't destroy your tools if you nick them) and the screws are very hard. It makes them seat a lot tighter than you realize you're turning them.

Definately just snug them down. I learned the hard way and now have to take the EZ-Out to my small PSI chuck. Been putting it off for a while, but need my smaller jaws for a project so gotta get it done.   

I don't remember putting them on tight the last time I swapped jaws, but that's what I tell my wife too about the caps on the soda bottles .

Since I don't swap jaws very much, I have thought about using that anti-sieze stuff like you use on spark plugs and stuff. What do ya'll think of that?