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View Full Version : self-locking screws/nylon patch



balddave
02-04-2008, 12:14 PM
Hey all I did the usual search routine and didn't find anything.

Does anyone have any clever ideas for something I could add on a screw to make it self locking, like the ones you can buy with the nylon patch on them. I need it to be adjustable though, so thread lockers won't work, I just want it to move only when I adjust it, not through vibrations and such. I have a handful of different sizes that I would like to add it to, and do not want to order new screws, they are oddball and expensive with the patches. I was thinking like silicon, or general caulking, but don't know how that would hold up or even work.

Thanks
Dave

BarryK
02-04-2008, 12:55 PM
Try a search for "nylock nuts" - should find 1000's

hitnmiss
02-04-2008, 01:02 PM
I read somewhere once to screw thru a plastic bag if you need a movable-locked screw.

Haven't tried it yet but might be worth a shot.

RobbieKnobbie
02-04-2008, 01:15 PM
What you're talking about is a perfect application for FlexLoc nuts. They are all steel nuts (no nylon) that have slotted crowns on top somewhat similar to a castellated nut but with much thinner slots. They squeeze the crown in slightly so that once you thread the nut down to the crown the stud has to un-squeeze the castellations.

They work extreemly well, are re-usable a thousand times (as opposed to nylon insert nuts that you're supposed to throw out once you remove them) and WILL NOT wander off.

you can get them from MSC and probably a lot of other industrial supply houses. (just search 'Flexloc')

fasto
02-04-2008, 01:42 PM
Does anyone have any clever ideas for something I could add on a screw to make it self locking, like the ones you can buy with the nylon patch on them. I need it to be adjustable though, so thread lockers won't work, I just want it to move only when I adjust it, not through vibrations and such.

Put Loctite 242 on the screw and LET IT DRY. Assemble. Voilla!

smiller6912
02-04-2008, 01:48 PM
I build some guarding for machinery and one of my punch press manufacturers specs in Flexloc due to their resistance to moving under heavy vibration. I like them a lot, they work great, and they work over and over unlike the nylocks that wear in and lose their grip.
If you only have a few to do, you might try squeezing your nuts in a vise (:eek: stop it) just a little. Try this on standard hardware first, a deformed thread or two is all you need.

Joel
02-04-2008, 02:11 PM
Dave is asking about male threads, so presumably a nylock doesn't solve the problem in his application.

You can make make your own locking bolts by drilling a hole and inserting some small dia nylon.

pcarpenter
02-04-2008, 03:53 PM
I have heard that string-trimmer line works for what Joel described.

I think it was Paul Alciatore who posted a recommendation here that involved using monofilament fish line by just sticking it in the hole before threading in the male componenet. It makes for a drag fit going all the way in.

I don't want to hijack this, but I had a bottle of something called Vibra Stop that was sold at an archery store. It came in a little bottle with a small brush in the lid (sort of like nail polish). You brushed it on male threads and let it dry. It left them rubbery and you screwed it together and it allowed for adjustment...even limited disassembly and re-assembly. Soaking in lacquer thinner would remove it. The stuff looked just like yellow carpenter's glue, but I highly doubt it was as that stuff dries hard. It eventually molded and I had to pitch it.

I have read that Loctite makes a similar product, but I do not recall the number. Wish I knew, however as with the demise of my bottle of Vibra-stop, I need something to do the same job.

I have also used clear nail polish on scope screws on firearms. It prevents vibration loosening, but it brittle enough you can snap it when needed....not a solution to something needing adjustment however.

Paul

timcasbolt
02-04-2008, 05:31 PM
There is a wealth of information on the Loctite website. Many of their products are intended for situations similar to what you describe.

Paul, was that Vibra-tite? We used that at work a long time ago for vibration resistance in lockscrew applications. Worked very well as I remember.

balddave
02-04-2008, 06:13 PM
Thanks bunch for all the replies, joel was correct I was asking about the male threads, I am familiar with the nylocks, but I've got a bunch to run with now, I'm sure one of the many suggestions will work.

Thanks again
Dave

darryl
02-04-2008, 09:54 PM
Painting on a little pvc cement would probably work in a pinch.

kniteshade
02-04-2008, 11:31 PM
I think I saw this in some cheap chinese toy (yoyo or something) once:
The bolt had a slot milled lenghtways along it, then a piece of nylon wedged into the slot. Once the bolt is screwed into the nut for the first time it cuts rough thread shapes into the nylon, and acts like a nylock.

coldformer
02-05-2008, 07:31 AM
i have used this product with good results
http://www.threadlockers.com/vibratite.jsp

Your Old Dog
02-05-2008, 07:43 AM
Dave is asking about male threads, so presumably a nylock doesn't solve the problem in his application.

You can make make your own locking bolts by drilling a hole and inserting some small dia nylon.

How about that stuff they use in weed eaters, you can get it pretty thick?


i have used this product with good results
http://www.threadlockers.com/vibratite.jsp

Makes me wonder if plain old acrylic artist paint sold in tubes would work nearly as well?

Paul Alciatore
02-05-2008, 09:29 AM
I have heard that string-trimmer line works for what Joel described.

I think it was Paul Alciatore who posted a recommendation here that involved using monofilament fish line by just sticking it in the hole before threading in the male componenet. It makes for a drag fit going all the way in.

.....
Paul

Yes, Paul I did suggest that some time ago. I'm surprised you remembered it and that it was me. I used the idea on the adjusting screws of some QC toolholders I made and they seem to still be working after some time. Like the nylock screws they are a one time use, but the neat thing about it is they are easily and cheaply renewed.