What size nylon insert for an M6 lock nut?

[donverse]

I'm designing something and part of it has a aluminum block that will be have a M6 threaded hole. I want to add a nylon washer to give it a stop nut or lock nut type of feature. I'm looking for input into the appropriate diameter and dimensions of the washer. also I'm wondering if there are any special considerations for the housing of that washer or would I just simple create a housing/cutout that would fit the washer? Nylon/POM type? Thanks for any insight.

 

[jrmichler]

Nylon or UHMW make excellent elastic stop nuts. If you want to use a plastic block inserted into a tapped metal block, machine an elongated slot into the metal block and use a rectangular piece of plastic. You need to have a positive means for preventing the plastic from rotating. You do not need to tap the plastic, but expect (some experimentation is needed) to drill the hole larger than normal tap drill diameter, and smaller than 6 mm. You may want to partially tap the plastic after installing in the metal block to make it easier to start the bolt.

Another technique is to put the plastic into the bolt. Cross drill the bolt near the end, and insert a piece of plastic. The plastic can be a tine from a comb, a piece of weed wacker cord, a piece of large diameter monofilament fishing line, or any small diameter ductile plastic. Poke the plastic through and cut off with a pair of diagonals (side cutters).

My father had an early model Ruger Super Blackhawk 44 Magnum. At the time, it was the most powerful handgun on the market, and it had a reputation for shaking the screws loose. He got tired of tightening the screws every time he shot the gun, so cross drilled all the screws and used tines from a comb as described above. It worked. The screws stayed tight. And he only used full loads.

Side note: I learned to shoot handgun with that gun. Same full loads, of course. I was in my early teens, and small for my age, so I used both hands to hold it. With a relaxed stance, every shot ended with the gun over my head, and me bouncing back about ten feet. Walk forward, load another round, shoot again. The other club members found the whole scene very entertaining.

 

[Tom.G]

Both bolts and nuts with Nylon locking inserts are widely available commercial items, and they work.
https://nylok.com/products
Cheers,
Tom

 

[donverse]

Nylon or UHMW make excellent elastic stop nuts. If you want to use a plastic block inserted into a tapped metal block, machine an elongated slot into the metal block and use a rectangular piece of plastic. You need to have a positive means for preventing the plastic from rotating. You do not need to tap the plastic, but expect (some experimentation is needed) to drill the hole larger than normal tap drill diameter, and smaller than 6 mm. You may want to partially tap the plastic after installing in the metal block to make it easier to start the bolt.

Another technique is to put the plastic into the bolt. Cross drill the bolt near the end, and insert a piece of plastic. The plastic can be a tine from a comb, a piece of weed wacker cord, a piece of large diameter monofilament fishing line, or any small diameter ductile plastic. Poke the plastic through and cut off with a pair of diagonals (side cutters).

My father had an early model Ruger Super Blackhawk 44 Magnum. At the time, it was the most powerful handgun on the market, and it had a reputation for shaking the screws loose. He got tired of tightening the screws every time he shot the gun, so cross drilled all the screws and used tines from a comb as described above. It worked. The screws stayed tight. And he only used full loads.

Side note: I learned to shoot handgun with that gun. Same full loads, of course. I was in my early teens, and small for my age, so I used both hands to hold it. With a relaxed stance, every shot ended with the gun over my head, and me bouncing back about ten feet. Walk forward, load another round, shoot again. The other club members found the whole scene very entertaining.

There's a lot of good stuff here jrmichler! Thanks for this and the entertaining story. : )

 

[donverse]

Both bolts and nuts with Nylon locking inserts are widely available commercial items, and they work.
https://nylok.com/products
Cheers,
Tom

Tom, thanks. I realize that but that's not what I need for this project.

 

[mthiru555]

Here you can see dimensions for M6 size https://itafasteners.com/products-nuts-nylock-nut.php

Hope this help. Thanks

 

[Dullard]

I'm not sure what you're building, but:
Most purists advise against re-use of the kind of elastic locking device you're contemplating; they are one-shot only. I don't necessarily agree (for most applications), but you should be aware of the sentiment. It may be ignored, or addressed by making the 'consumable' easy to replace (assuming that disassembly is a possibility).

 

[Baluncore]

I expect the aluminium will gall if you do not use a steel coil thread insert. You might consider using a compound that locks the thread and prevents galling of the aluminium. The original brand is called Loctite.
https://en.wikipedia.org/wiki/Thread-locking_fluid