Thread locker to keep un-torqued screw in place

[EdwardC]

I have some machine screws that I need to screw into a metal structure (threaded). The machine screw needs to tighten down and hold another piece of metal, but I don't want it tight since I want the middle piece to be able to pivot and spin as needed. I feel that a nylon lock nut would be ideal for what I want (if the other side of the screw was accessible), but it's not.

So my question, is there a certain type of thread locking compound that would work best at keeping a machine screw locked in place while that screw isn't torqued at all? It's a fairly high vibration assembly, so I'm afraid that if I don't do anything, the screw will back out. I'd prefer it to be removable, so my first choice was to use a medium thread locker, or Vibra-tite VC-3, which I think both would be adequate, but I'm curious if there's a better product out there.

Thanks, I hope my description made sense!

 

[andyd]

Use a shoulder bolt and a ny-lok nut.

 

[EdwardC]

Thanks, I hadn't thought about swapping out the fastener, a shoulder bolt of appropriate length isn't a bad idea at all. I don't have access to the other side (basically a tapped blind hole), so I can't use any kind of nut (or else I'd just throw a normal nut on as a jam nut).

With a shoulder bolt, I could properly torque it down. I might be wrong, but my assumption was that most common thread lockers relied on the fastener being properly torqued to work right.

 

[zrxkawboy]

Vibra-tite sounds ideal for this situation.

 

[Trav]

+1 on the shoulder bolt, a full threaded machine screw with loctite is the wrong fastener for this job. You can use thin nylon washers to take most of the play out and have smoother movement.

 

[BrocLuno]

+2 on shoulder bolt.

I use PVA wood glue on clean threads. Always comes loose when needed. Holds pretty well while in place. Poor mans Lock-Tite

 

[Johnny2Bad]

Multiple options:
-Those already suggested
-Stake the top of the bolt / fastener
-Use Nail Polish (=lacquer and pigment, but can be borrowed or buy a close-out bottle at the pharmacy for $1) over the top / side of the fastener / bolt threads
-Solder (permanent, essentially) with a heat gun instead of soldering iron providing the heat
-Epoxy (a small ball of putty epoxy would be perhaps ideal at just one point of the top of the fastener / thread interface, could just grind off that part of the threads to remove the fastener, the remaining threads would allow removal / re-assembly)

I'm sure there are other options.

 

[Ducked]

polythene film from a bag of appropriate thickness.

(Poor man's Nylock)

 

[EdwardC]

Thanks everyone! I have several of these to assemble, so I may try a few different methods you guys listed and see how it turns out. I think my first trial is to see if I can get the proper length shoulder bolt.

I actually really do like the idea of thin nylon washers, I want the part to be able to turn, but I don't want or need it to turn super freely, a little resistance would be perfect actually.

Thanks again!