About locking screws down

[boyardee12]

Iim wondering are there any nuts that lock on the screw and wont nudge even if  i don't tighten it all the way if not  is there some kind of thing that lock down on the screw. I'm asking this because i need to have the arms of a gripper loose and when i use just a nut i have to unloosen it a little and then the nut get more and more loose.

the screws/bolts im using ar e 3/8 and 5/16 btw

[Steve Joblin]

try using two nuts... screw the top nut down hard on the bottom nut and both will "lock" onto the bolt.  The other alternaive is to use thread lock.  Yet another alternative is to position the nut where you want, then drill a hole through the nut and bolt, and then secure it with a cotter pin.

[pomprocker]

make sure the second nut is a locknut

http://en.wikipedia.org/wiki/Locknut

[ed1380]

make sure the second nut is a locknut

http://en.wikipedia.org/wiki/Locknut

not necessary. both nuts can be regular. just tighten them against each other

[Spoil9]

If you have a way to drill, you could drill a hole in the end of the bolt and use a castellated nut, or buy some red Loctite.
I believe Blue Loctite is stronger than Red but I may be backwards. By using the lesser of the two you can take it off later if needed with out a lot of hassle.

[boyardee12]

simplest way is two use two bolts i guess which i have been doing and its ok for now. if i run into problems i brobly will get some thread locker.

Thanks everyone for helping.

[Admin]

I'm asking this because i need to have the arms of a gripper loose and when i use just a nut i have to unloosen it a little and then the nut get more and more loose.

This problem should not be solved with nuts.

The problem you are having is that you are screwing a joint, that should rotate, really tight. Obviously being tight will make that joint freeze and not work.

The correct solution would be to use a bolt, where the non-threaded region is for your joint, and the threaded region is for your nut. You can also use a small plastic tube and a long screw inside it as a joint, where the nut just holds it all together.