11

So I got "creative" with these shelves I installed. Looking for ideas to keep these nuts from loosening. I considered just gluing them in but that would make it annoying in future if adjustments are required.

Thoughts?

enter image description here

I know they have nuts that specifically are supposed to not loosen but that requires me taking it apart more than I'd prefer.

Thanks

  • 27
    Use two nuts, and tighten them against each other. – Hot Licks Dec 18 '17 at 4:50
  • I'd have put a nut/washer on the top of the shelf so you could tighten it. Frankly though I don't think it will go anywhere if you just leave it as is. – agentp Dec 19 '17 at 15:51
  • although it's not its intended use, from my experience PTFE tape does work wonders with screws that are prone to unscrewing; after having the screws on my bike unscrew every couple of weeks, I've gone the PTFE route and the problem stopped. – vaxquis Dec 20 '17 at 14:02

10 Answers 10

32

If you use a product known generically as anaerobic thread locker, you will prevent the rotation of the fastener unless it is done by a wrench. Locktite™ is one such brand name, although many other names abound. Do not use the red version, as it is nearly permanent, requiring application of intense heat to release. Blue is medium and holds well under vibration, while green is considered low strength. For your application, one would expect even green will work well, although in my experience it is rare to see it on the shelf. You can find threadlocker in red and blue at most auto parts stores and certainly in a well stocked hardware store.

Until I read the Loctite page, I wasn't aware there is also purple threadlock.

As noted in the text from the web site, use caution on selecting the product. The packaging/bottle color is not a good indication of the holding strength.

  • My experience is that Green has never worked for me. I often use a dab (not the full soak all the threads amount) of Blue for these types of things even though it's probably overkill just because I have Blue laying around for use on my car. – Brian Knoblauch Dec 18 '17 at 13:12
  • 1
    Loctite make a huge range of threadlocker products, many of which have the same colors. Please consider specifying the actual products rather than just the color. – Peter Green Dec 18 '17 at 21:08
  • 1
    According to the linked Loctite™ page, the threadlocker line consists of four colors, each of them assigned to a specific strength. The color refers to the liquid contained within the bottle, of course, not the color of the bottle. If you've discovered, for example, there are two different strengths of red threadlocker, please expound. – fred_dot_u Dec 18 '17 at 21:53
  • Nuts are supposed to tighten against something, so the thread locker only prevents them from loosing up. For op's free floating nuts, even the strongest thread glue might not be enough. – Agent_L Dec 19 '17 at 14:08
  • 1
    Nuts that are properly tightened against something will usually not loosen unless subject to vibration or other forces. If the boards do not have a nut on top, the nuts could walk down the rod under vibration from use. Thread lock adhesive will indeed prevent the nuts from movement. Even when blue thread lock is in place and cured, cracking it free with a wrench does not always result in easy movement until the nut has cleared the treated area. Red thread lock adhesive will not release unless heated. – fred_dot_u Dec 19 '17 at 16:35
16

The answer is simple: Lock washer.

It looks like a washer but it's split, and slightly bent to form a spring compression against both surfaces and locks them together. Hence, "lock washer." There are various types of lock washers (I'm technically referring to a "split washer"). The split ones are most common.

They're simple, cheap, and effective.

Check out the Wikipedia article on washers (or Google) for pictures of split washers. They're available at almost any store with a hardware aisle.

  • 4
    Don't they need something to clamp hard against? The shelf looks like it's floating. – jkd Dec 18 '17 at 10:35
  • 1
    @jakekimdsΨ is right, this would only work if shelves are secured both above and below, but we can't see if that's the case, and I doubt it is. – Mołot Dec 18 '17 at 11:14
  • Yes, a lockwasher absent compression will do nothing. – Harper Dec 18 '17 at 13:45
  • 4
    Note though that he DID say he didn't want locknuts because he doesn't want to take the nuts off to replace them (furniture is built, replacing nuts is a nuisance). Applying a lock washer is subject to a similar level of inconvenience and would hence not be a preferred option – Caius Jard Dec 18 '17 at 14:18
12

An even cheaper solution is locknuts, which are different to nyloc nuts.

Locknuts are simply second nuts threadded on at the same time as the main load bearing nut.

Then you oppose the two nuts by tightening them against one another.

Locknuts are often thinner, and strangely they cost more than normal nuts, so its totally workable to use two normal nuts threadded onto the rod together.

This technique is used in bicycle wheels, where one nut is a bearing race, and the outside is held in position with a thin locknut. Its only expensive pro bikes in the last decade have gone away from this, the vast bulk of bikes still use this.

My car's wheel bearings are held on by two 2 1/8" nuts, cinched against each other in this matter.

Here's a nyloc nut

http://media.rs-online.com/t_large/F0521951-01.jpg

and here's a locknut - as you can see its quite thin.

https://media.rs-online.com/t_large/R7417654-01.jpg

7

Post fab, your only choice is threadlocker as Fred describes, or really, any sort of glue will do, maybe even nail polish.

Pre-assembly, you use

  • two nuts, and fix them by cranking them in opposite directions so they bind.
  • "Nylok" or other binding nuts. However this is a nightmare to assemble because they will not easily turn, and you must turn them rather far... All the while struggling to hold the threaded rod firm without damaging the threads (which would make it impossible to disassemble).
  • pipe or tubing as a sleeve around the threaded rod, which then allows you to tighten the screws, putting the sleeves in compression which binds the nut. Of course the tube lengths define the spacing and are not adjustable.
  • 1
    Super-glue (cyanoacrylate) works pretty well too as a thread locker. – Criggie Dec 18 '17 at 7:32
  • Back when I worked in construction we always double nutted items on threaded rods. Of course, we always had the extra nuts to do it because we were already at the store buying all the stuff. Nowadays I mostly do repairs and typically do not have the correct nuts on hand... – Brian Knoblauch Dec 18 '17 at 13:16
5

My preferred solution is to use locknuts, which have a nylon insert that grips the nut.

Or, as fred_dot_u mentioned, Loctite.

  • 10
    I shudder at having to drive a nylon lock nut up 3 feet of thread. – user71659 Dec 18 '17 at 3:32
  • 2
    @user71659 - Use the drill on the bolt head, then a wrench on the locknut - no problem. – William - Rem Dec 18 '17 at 3:48
  • 1
    Except no bolt has 3 feet of thread. He's dealing with threaded rod, which is annoyingly hard to hold. – Harper Dec 18 '17 at 6:13
  • 2
    Threaded rod fits fine in a drill chuck. If you're concerned about damaging the thread, just leave another nut in front of the chuck, then wind it back over the damaged section when finished. – Someone Somewhere Dec 18 '17 at 6:49
  • Sounds like a good use for a lathe. – Criggie Dec 18 '17 at 7:31
2

A simple dab of clear silicone calk will also to the trick. Apply it where the threads of the rod exit the existing nut.

1

I often had these situations especially in installing professional light equipment. The best (and cheapest) solution I found was adding a second nut.

First you use your first nut to find the desired distance, than you get your second nut to this location. While keeping the first nut on its place with a wrench, tighten the second nut with another wrench.

1

Or, post-installation, drill a small hole through the nut and rod and place a locking pin or wire in the hole. See Hairpin Locking Pin. The trouble will be finding one small enough. You can re-drill later if you end up changing the configuration (or switch to nylon nuts).

1

I suspect they will not move in any noticeable way.

It depends on lots of things like vibration and force that the nuts are resisting.

I would suggest just leaving it alone and seeing if you have anything to fix.

0

Use A 1/4 inch tie wrap to grip the threads below the nut.

  • By tie wrap do you mean a zip tie or cable tie ? Not particularly load-bearing. – Criggie Dec 19 '17 at 6:20
  • 2
    doesn't need to bear any load, just stop the nut from turning. – KevinDTimm Dec 19 '17 at 14:55

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.