immobilizing a nut?

[Tai Fu]

Suppose I have a Acme threaded rod (otherwise known as a lead screw) and a few nuts... I want to have one nut in a position and frozen in place so that it can bear against another surface... but other than locking two nuts together, which proved to be unreliable (one nut moves and defeats the whole lock system) does anyone have a better way of freezing a nut to their thread? Some mentioned welding but I don't have a welder... do you think those bandsaw blade brazing strips will work? Another idea I have is drill/tap the nut for a set screw...

[John Downey]

You can braze it if you have enough torch and it is mild steel (as in not heat treated).
You can also soft solder it, that will be plenty to keep it from rotating.

Set screw would work, maybe two of them, just in case. You could even use lock tight or CA glue. You can also peen the threads or the edge of the threaded hole of the nut with a sharp punch - deform the threads to lock it on.

[John Lanciani]

How about red Loctite?; http://www.henkelna.com/industrial/red-threadlockers-permanent-high-strength-12892.htm

[Pat Houle]

you can get Loctite, available at part stores and some hardware store, blue for medium hold, red for a more solid hold. I bought the new "format" of Loctite in a stick/paste format. Less messy than the liquid format.

[Mark Bolton]

Drill a hole an insert a roll pin. By far the best option because its "un-doable" with a simple dowel punch. If you want it even easier drill a hole and insert a nut and bolt.

[keith micinski]

If not a roll pin you could also use a threaded Allen jamb screw.

[Erik Loza]

...a threaded Allen jamb screw.

This ^^^^

I would drill the nut, tap the hole, then insert a recessed allen-head grub screw. If you do this, however, I would make sure to apply (very tiny amount of) anti-seize paste to the grub screw before you tighten it. Reason being that most of the grub screws out there have a "black oxide" finish, which is not at all rust resistant, so they tend to seize into place pretty readily. Best of luck with it.

Erik Loza
Minimax USA

[Michael Wildt]

Instead of a nut you can use a lock collar as listed below or you may have one already from a counter-sink drill bit or dowel drill bit, though that one wouldn't be threaded.

http://www.globalspec.com/industrial-directory/ACME_threaded_collar

Else follow Erik and Keith's recommendation.

[Keith Outten]

Drill through and use a cotter pin. It won't come out unless you want it to and you won't have to worry about threads or having to lock another threaded fastener.
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[keith micinski]

It probably would be easier to just drill all the way through And use a roll pin.

[Ronald Blue]

Will you have a need to adjust it after you lock it in place? The set screw idea would be best if so. If not pinning it would be easiest. You could also go with the setscrew and put a dimple in the screw with the tap drill size drill bit and it would be a positive lock also if no adjust is desired.

[Jason White]

Maybe add another nut and use it as a "jam" nut?


Suppose I have a Acme threaded rod (otherwise known as a lead screw) and a few nuts... I want to have one nut in a position and frozen in place so that it can bear against another surface... but other than locking two nuts together, which proved to be unreliable (one nut moves and defeats the whole lock system) does anyone have a better way of freezing a nut to their thread? Some mentioned welding but I don't have a welder... do you think those bandsaw blade brazing strips will work? Another idea I have is drill/tap the nut for a set screw...

[Tai Fu]

It's not reliable... sometimes they can work itself loose.

[Jim Andrew]

Lock tite and long wrenches. Double nutting works if you can get it tight enough, and the lock tite will glue the nut to the threads.

[Chris Fournier]

In a recent thread you mentioned that you lived close to metal workers alley and that the cost of having machinists work for you is reasonable. Take your design to them if this is the case and pick up the assembly when they call you.

[Dave Kirby]

JB Weld. If you never want it to move again, that'll be the easiest way to do the trick!

[Myk Rian]

Maybe add another nut and use it as a "jam" nut?
You didn't read the entire post, did you?