Fixing stripped nylon threading

[shorne]

Is there any recommendation for repairing parts where the nylon threading has been stripped?

For example, some the threading in my stealth transmission case where it connects to the chassis brace are stripped. The screws hold in ok but if I tighten them too much they loosen up again.

[GoMachV]

To repair the hole, I have heard of people melting a plastic/nylon of the same type with a chemical- laquer thinner maybe? And using it as a putty to fill the hole. It should "bond" itself well enough to drill out the holes once it hardens. I have not tried this but it sounds like a jb weld type fix and those have always worked for me

Personally I move to a 5-40 or 3mm screw and all is fine

[jwscab]

this also sometimes works:

put oil on the screw threads. apply a dab of medium CA to the damaged hole. apply oiled threads with the intention of leaving the threads in place(ie, don't try this temporarily, do this at the final install of what you are working on.) The glue will form threads, but will also probably stick somewhat to the metal screw threads, hence the oil. the oil gives you a chance of the bond happening to the plastic, more than the metal, for dis-assembly later. this will give you a nice strong threaded joint, but will usually have to be redone again if you take it apart. not something for high strength areas, or something that gets adjusted, like tie rods.

[rctenracer]

http://www.ebay.com/itm/NEW-Perma-Coil-4-40-Thread-Repair-Kit-Uses-Helicoil-/300664235052?pt=US_Hand_Tools&hash=item4600fc242c&vxp=mtr#ht_4650wt_906

[GoMachV]

Dang...that's one tiny helicoil!

[AYKBOBCAT]

I have the same question but for cast metal. I have a gear case with a stripped screw hole. There should be some cement that I could use to fix that I guess?

[shorne]

I have the same question but for cast metal.

For metal the are a few resources on the web I found before asking here. Like here they mention filing the hole with welding then re drilling or using helicoils.
http://diy.stackexchange.com/questions/16815/how-can-i-fix-a-stripped-hole-in-an-aluminum-piece

For nylon I wasn't sure what to fill with.

[shorne]

To repair the hole, I have heard of people melting a plastic/nylon of the same type with a chemical- laquer thinner maybe?

Yeah I was thinking that but not to sure where to get the right kind of plastic or what thinner would work best.

I was thinking job weld might be to hard to properly mesh with the threads. Is that not the case?

So I was thinking maybe filling with some kind of paint and drilling would work.

Personally I move to a 5-40 or 3mm screw and all is fine

I was thinking of doing that too. But I am a bit of a purist so using original spec screws would be preferred.

[klavy69]

But I am a bit of a purist so using original spec screws would be preferred.

a purist would replace the damaged threaded part .

Todd

[shorne]

But I am a bit of a purist so using original spec screws would be preferred.

a purist would replace the damaged threaded part .

Really? I would rather keep the original part. Maybe I'm not a purist? Maybe just cheap

[THE H.P FREAK]

HI!... I use these on stripped out RC plastic/nylon parts. They work great.

http://www.tonysscrews.com/category.sc?categoryId=12

[klavy69]

Really? I would rather keep the original part. Maybe I'm not a purist? Maybe just cheap

an original replacement part is an original part to most purists. A re-re part will spark an explosion to most purists.

I can absorb what you are asking/meaning though...I am by far cheap . Many a time to buy a complete car for a part I'm after just to try to revamp my paypal by getting rid of what I don't need after the fact. Getting too lazy as of late though so running outta room

I've done alot of what jwscab mentioned above but without the oil. Just ca'd the screw in. If you have decent tools the steel screws will come back outta the nylon...just have to glue it in again like he mentioned.

Todd

[GoMachV]

I've done alot of what jwscab mentioned above but without the oil. Just ca'd the screw in. If you have decent tools the steel screws will come back outta the nylon...just have to glue it in again like he mentioned.

Todd

If anyone is watching just tell them it's thread locker. Yeah, that's the ticket!

[klavy69]

If anyone is watching just tell them it's thread locker. Yeah, that's the ticket!

funny you say that, reason for doing it the first time was my threadlocker was dry and didn't want to buy anymore (insert 'cheap' here) so I ca'd my gt's rear bulkhead screw in one side . You might've noticed I said steel screws in my last post...aluminum doesn't let go so nicely

Todd

[DennisM]

I have the same question but for cast metal.

For metal the are a few resources on the web I found before asking here. Like here they mention filing the hole with welding then re drilling or using helicoils.
http://diy.stackexchange.com/questions/16815/how-can-i-fix-a-stripped-hole-in-an-aluminum-piece

For nylon I wasn't sure what to fill with.

Good luck on welding a 3mm hole shut in old cast aluminum

In Denmark we´ve got something called chemical metal, from PLASTIC PADDING. I.E I´ve used it to repair a broken mount on a clutch housing for 1/1 car.
If proper preparred (cleaned) it will hold.