[tutorial] Threading!

[Nodroz]

Hello guys,

I had some problems with my screw's threads on my engine. I didn't want to replace the whole case, so I decided to re-thread.

Tools needed (See the pictures. I don't know the English names, sorry. EDIT: Thanks to r-chez, the tools now have a name!)

Helicoil tool

Tap and tap wrench

Helicoil

I have found all these tools in my local repair shop. He gave me his tools for 1 day so I could fix it myself.


1. Get a tap and a tap wrench. Be sure it's the correct size for your hole! Mine is an M10. However, this is slightly bigger than an M10. You make the new thread bigger than the previous one. Then thanks to the helicoil, the thread will be back to a normal M10.

You go very slow, in clockwise direction into the hole. DON'T do this with an electric bore. Simply DONT. Be sure you're going straight in the hole. You don't want to go a bit skew and you'll completely ruin it. To get it straight it takes some time and patience. Just slowly turn it and watch what you're doing. Once you got it straight in for about 2 cm, you're almost done. Keep turning the tap wrench slowly in the whole to make your thread. Don't forget to oil it often, so everything goes a little bit smoother.
Go as deep as you need to. It's better that you go a little bit deeper than it should be. Once finished, slowly turn the wrench back out. This shouldn't be too hard.

2. Once finished with the re-threading, it's time to get the helicoil inside it. These are special rings designed for this. You screw it in and when you're sure it's at the good location, you turn counterclockwise. You'll need to put a little bit of force onto it. Suddenly the little pin that's used to get it inside the thread will break off and your thread is done!

(You can see the little nipple. That's nothing, once you screw in your screw it'll gone.

This proces takes time and patience. But it is cheap and better than replacing the whole engine's cover just because for new threads.

I hope you understood a bit of my explanation. It is quite hard to explain something like this in English for me, though.

Hope it helped!

Regards,
Nodroz

 

[r_chez_08]

Ah sweet you helicoiled it (a helicoil is the little spring like thing that you used).
The English names for your interest-
Tool 1: helicoil tool.
Tool 2: tap and tap wrench.
Part 1: helicoil.

I have some stripped threads which I think I might helicoil. They are to hold on a recoil shroud. The little kits are about $10.

Thanks for the tutorial, do you think you could use pliers instead of tool 1?
I have a tap and tap wrench.

 

[Nodroz]

Ah sweet you helicoiled it (a helicoil is the little spring like thing that you used).
The English names for your interest-
Tool 1: helicoil tool.
Tool 2: tap and tap wrench.
Part 1: helicoil.

I have some stripped threads which I think I might helicoil. They are to hold on a recoil shroud. The little kits are about $10.

Thanks for the tutorial, do you think you could use pliers instead of tool 1?
I have a tap and tap wrench.

Thanks for the names! Changed the first post according to these names.

I don't suggest to use pliers, you won't be able to break off the little nipple easily. Altough, with a bit of patience I think you'll be able to do it.

 

[r_chez_08]

Thanks. Do you think a small steel bar with a notch in the end would be OK?
BTW the nipple is called a 'tang' according to helicoil

 

[Nodroz]

Thanks. Do you think a small steel bar with a notch in the end would be OK?

What do you mean with this?
And thanks.

 

[Bluethunder3320]

wow, for someone who learned english through repair manuals (am i right?) youre doing a great job. i would be clueless.

i have never used a helicoil but i have an engine with a stripped exhaust bolt, maybe i will do it now

 

[r_chez_08]

I agree bluethunder. We have exchanged a few PM's, could not believe it either.
If you didn't say you were from Belgium I would not have known.

What I meant was get a steel bar just under 6mm for the 6mm helicoil, get a hacksaw and cut a slot in the end to screw the helicoil in. I can draw up a pic if you want.

Edit: I would like to add- when using a tap wrench you should reverse the direction routinely to remove any swarf (metal fillings) otherwise the tap can jam up and break, causing a far greater issue than you started with. I usually go 1 turn forward, 1/4 turn back etc, but there is an exact number you are meant to do IIRC.

Maybe this could be moved to the FAQ section or stickied? It seems too good to be lost.

 

[Nodroz]

wow, for someone who learned english through repair manuals (am i right?) youre doing a great job. i would be clueless.

i have never used a helicoil but i have an engine with a stripped exhaust bolt, maybe i will do it now

Thanks for the compliment. After all the hard learning and reading was worth it!
I get teached English at school, only 2 hours a week though. I learned mostly on the internet - such as forums like this one, manual from engines, tutorials, etc.

I have heard good things about these helicoils. They're atleast as strong as a normal thread.

This was my frist time I did something like this. It's not that hard, but you need to be sure. You don't want a tilted screw.

I agree bluethunder. We have exchanged a few PM's, could not believe it either.
If you didn't say you were from Belgium I would not have known.

What I meant was get a steel bar just under 6mm for the 6mm helicoil, get a hacksaw and cut a slot in the end to screw the helicoil in. I can draw up a pic if you want.

I understand what you mean. That would actually be an cheap and easy tool. I think it will do the job...
As you can see in the picture below, the helicoil tool has a weird shape milled in. Not exactly sure why that's there though.

 

[r_chez_08]

Yeah, see what you mean. I have ordered some helicoils without the tools. I will see what I can do.

 

[Bluethunder3320]

helicoils are probably stronger than the original thread because theyre steel, and they cover a larger surface area

 

[souperman000]

good thread.

I love the WD-40 in another language

 

[pipehack]

good thread.

I love the WD-40 in another language

Also in 300ML

I have the head on my old triumph helicoiled for the rocker boxes. Haven't failed me yet.

 

[OzFab]

do you think you could use pliers instead of tool 1?

You can if you're careful, I've done it before, but I wouldn't suggest it under M6 unless you have really small pliers. To break off the tip just twist back against the thread

helicoils are probably stronger than the original thread because theyre steel, and they cover a larger surface area

No they don't, they cover exactly the same surface area as the original thread.

good thread.

Was that pun intended?

@ Nodroz: Great job; well planned & easy to understand for the beginners

 

[souperman000]

Was that pun intended?

I just realized that when I read pipehack's comment. Wasnt supposed to be originally but I guess now it is! :arf:

 

[fowler]

Good write up

But for the sake of instructions it is better to use terfolex or other cutting compound as the tap will last much longer

Not to say I don't get slack and use CRC or WD40 when I can't find some proper stuff

 

[Doc Sprocket]

I agree. I'd also like to add that it's a good idea when tapping threads to stop every couple of turns, and back out a turn before continuing. This helps break the chips and clear them into the tap's flutes.

 

[Nodroz]

I agree. I'd also like to add that it's a good idea when tapping threads to stop every couple of turns, and back out a turn before continuing. This helps break the chips and clear them into the tap's flutes.

Yes, I did this. Apparently I forgot to mention it in the tutorial. I'll update it later.

 

[Fallenleopard]

great tutorial,
i have an engine that has 3 threaded holes but the 4th looks like the threaded piece has just fallen out.
would it work if i just put a helicoil in?

 

[Doc Sprocket]

great tutorial,
i have an engine that has 3 threaded holes but the 4th looks like the threaded piece has just fallen out.
would it work if i just put a helicoil in?

There should be no "threaded piece", just threads. Probably stripped- it can look like the threads "came out". As long as there is still enough material in the hole for the helicoil drill size, there's no problem. If not, then you need to select a larger fastener and drill and tap to suit. (no helicoil)

 

[Fallenleopard]

There should be no "threaded piece", just threads. Probably stripped- it can look like the threads "came out". As long as there is still enough material in the hole for the helicoil drill size, there's no problem. If not, then you need to select a larger fastener and drill and tap to suit. (no helicoil)

thanks,
yeah i know it should be stripped, but it is smooth like there was never a thread there. so maybe i will just tap a new thread in.