Helicoil

[stuessenhigh]

Hi all...

I've moaned regularly on here about many of the threads getting wrecked on my Beta...especially those going into the frame..like the REAR bash plate ones. The common suggestion was to use Helicoil.

SO...eventually I would like to purchase this kit? and learn how to use it...BUT I have no idea about the procedure etc.

IF..anyone is doing one in the near future and wants to do me a MASSIVE favour..please post a few pics on what the tool looks like, and if possible...the procedure involved.

GO ON...I'll be yer best mate.

Cheers in advance if anyone has the time/energy to do this

[jtt]

No problem Stu...here we go....

Basically what the kit contains is an appropriate sized drill bit, a tap, a "helicoil" and a driver to put it in. The drill bit and tap are pretty self explanitory. Basically you are drilling out the hole bit enough for the next size up tap. The helicoil itself is a stainless steel coil, that matches the thread perfectly. You tap the hole to the next larger size, then thread in the helicoil and it brings the thread back to the original size you desired. The driver is little more than a threaded bolt that the coil threads onto and then is threaded into the freshly tapped hole.

There a simple setup and very strong. The kits are a bit expensive, but a worthy addition to any toolbox

Hope this helps.

I should have mentioned that the "helicoil" in the picture is not the one that goes with the bit and tap...I just showed a larger one for clarity.

Edited November 13, 2004 by JTT

[sirdabsalot]

Hello Stu--

I've been through more than my share of messed up threads also, and have found Helicoils to be lifesavers. It is such an easy process that I now install them in any hole that is high use (such as the screws securing the air filter cover) or high stress (such as the disk mounting bolts).

As JTT said, it just involves drilling and tapping, then inserting a coil spring (a simplification) into the tapped hole. The tap is not the next size up, though. It is a special size for the helicoil (because of thread pitch). Also, there are different types of installation tools, including the type already mentioned, as well as one the slides through the helicoil and has a groove in the end that the tang of the helicoil fits into. Once installed, the tang is broken off and you are left with clean, strong threads.

Another point is to make sure you tap full threads to accept the entire length of the helicoil (which can be ordered in different lengths). If the bottom end of the helicoil gets into the portion of tapped threads that are tapering down (from the tapered end of the tap), you may not be able to fully insert the helicoil. If this happens, you either have to cut the remaining threads off or get a helicoil remover and tap the hole with a bottoming tap. If the helicoil does get into the taper, the screw will be difficult to install.

More than you wanted to know?

Cheers,

Richard

[stuessenhigh]

Thats great guys..special thanks to JTT for the pics.

SO..Just a couple of things...(probably being a right doughnut here)....dont really understand what a "tap" does that the drill wont have already done.

ALSO..if a hole was already helicoiled..(I think for instance the rear bash plate holes on the Beta are)..could I just pull out the old thread and insert another of the same size..without any drillling etc??

I assume that one really needs lots of different size drivers to insert the coil???depending on the coil size??...and I assume there is another? tool for pulling out old/knackered helicoils?

SOrry for all the (probably dumb) questions...hope you dont mind me bothering you all further

THANKS

[beta boy]

on my techno i had helicoils put in the sub frame, and one day i was putting my sub frame back on put the bolt in and as i was doing it the helicoil was comeing out. do you think it would be a good idead to put a bit of super glue in at the same time to stop this from happening

[jtt]

Of course your correct on the "next size tap" thing Richard, I was just trying to simplify, but may have added to the confusion.

Stu, each helicoil kit is for a specific thread and size. So there is a different drill, tap, coil and driver for each different thread.

The reason for the tap is that the coil actual threads into the drilled out hole. This is why the tap is specially designed as it must match the coil being installed. Basically, the coil is a male thread with a female thread on the inside. It literally threaded into the hole you drilled and tapped. Confusing to describe, but simple in practise.

As for removing them....I'm not sure. I think there is a special tool, but have never seen or used one myself. They are generally a one shot fix. The little coil is somewhat like a chinese finger trap, if you know what I mean...it goes in, but traps itself from coming out. If you try to turn it counterclockwise to remove it, it generally just binds itself in tighter against the outer radius of the hole.

BB, if you are having one back out, a dab of green locktite or Locktite bearing mounting stuff will bond it in there, I'd think.

[charliechitlins]

Thats great guys..special thanks to JTT for the pics.

SO..Just a couple of things...(probably being a right doughnut here)....dont really understand what a "tap" does that the drill wont have already done.

ALSO..if a hole was already helicoiled..(I think for instance the rear bash plate holes on the Beta are)..could I just pull out the old thread and insert another of the same size..without any drillling etc??

I assume that one really needs lots of different size drivers to insert the coil???depending on the coil size??...and I assume there is another? tool for pulling out old/knackered helicoils?

SOrry for all the (probably dumb) questions...hope you dont mind me bothering you all further

THANKS  

Being that the helicoul is like a spring, it has threads on the outside as well as on the inside. That's what the tap is for--so the 'spring' will thread in to the hole.

The driver comes with each kit.

If you go mail-order, there's a new kind of kit that I got by mistake. It has several different length coils and comes in a big plastic box that takes up a lot of space. Not worth the extra $$ IMO.

Helicoils are hard spring steel and I have never known one to get knackered. If one does, it could be grabbed with needle-nose pliers and yanked out. Then you would just be able to screw another in.

Beta boy...Helicoils work best in blind holes. If you use one where the hole is open, make sure you clip the coil so it doesn't protrude through the back. This will prevent it from coming out with the bolt.

If that doesn't work, try some loctite.

[sirdabsalot]

JTT and Stu--

There is a tool for removing the helicoils. You give it a tap with a hammer and turn the helicoil out while holding pressure. It's available at McMaster-Carr, on page 3061.

Cheers,

Richard

[stuessenhigh]

WOW...this is amazing..I might have actually learned something at school if there was internet in those days.

What can I say...thanks to everyone for answering my doughnut questions I think i will try and buy a kit soon and try to find something to practise on first.

BUT..just one last doughnut question..that will help make it REALLy clear to me...In your picture JTT is the driver the second from left and the tap third from left?? .................NO laughing!!

[jtt]

Yup!