Helicoils? One time fix?

I have been having a discussion about helicoils and would like to bring it to the board.

Are helicoils one time use items? In other words, do you use them to get out of a jam, but replace the part the next time the fastener need to be removed? (assuming it's possbile)

One concern is that the removal and replacement of the fastener will damage the helicoil.

We are talking about just helicoils and not a threaded, steel insert. Just the spring-looking thread 'repair' item.

So who wants to throw their change on the table for discussion?

According to this, they are a permanent solution.
Helicoil

I will agree with QuickTD. I use helicoils in my line of work. I manufacture circuit boards for many big name corporations and we install then regularly to back up aluminum threading. Once they are in you can run a screw through them a thousand times and they're still good.

I, too use helicoils in my work and they are subjected to much more stress than on a circuit board. The bolts also get tightened to much higher torques. Like 3000 ft-lbs. and some of them get R&R once a year.

Typically I work with all steel components, but sometimes I run across helicoils in aluminum. Since the helicoil is what is contacting the aluminum and it has a larger diameter than the bolt, the strength of the joint is stronger than with just the bolt.

The helicoil is a great choice where a high torque is required, but there are space limitations. If, say a 14 MM bolt with standard torque would give the required clamping force, but there is only room for a 12 MM bolt, put in a helicoil, then use a 12 mm bolt that can be torqued to what the 14 MM bolt would be torqued to. The threaded part of the joint is now strong enough to get that torque of the 14 MM, but you can use a smaller bolt.

As far as frequent R&R of the bolt, I would rather use a helicoil and R&R the bolt correctly (IE-no impact) especially in dissimilar metals. The steel alloy turning against the aluminum causes galling of the aluminum, thereby weakening the threads. With the helicoil (or other threaded insert) you now have a steel alloy turning against a steel alloy. Much better.

Thanks for the feedback. Any others?

If you did loose faith in an installed helicoil, how would you get it out?

Pick and a screwdriver and patience. Then install a new one.

Bump. Any other input, helpful or otherwise?

Helicoils are considered a permanent repair. If installed correctly they do not back out or sustain damage easily.

Of course if you install a Helicoil and then thread in a cross threaded bolt you will damage the coil, (as you would by threading a cross threaded bolt into just about any material).

When I worked at an air cooled VW repair shop we used Helicoils exclusively for the exhaust manifold studs that always tended to rust and break off in the aluminum head, (taking the thread with it when you tried to remove the broken off stud).

Helicoils...they're not just for repair.

We put them in aluminum all the time. Much stronger and much more desirable if repeated assy/disassy is required.

I personally like Keenserts better, but they cost a lot more.

Thanks for the tip CP. These look very user friendly & I like the locking mechanism. Posted a few links for this product:

http://www.stanleyfasteners.com/catalog/ch8/AuvecoCatalog/pg_0093.htm
http://www.source-products.com/new_items/read_more_keensert.htm
http://www.newmantools.com/kee.htm
http://www.mcmaster.com/ (do a search for Kleenserts)

Last time I had the oil changed they told me that I had a problem with the oil plug being stripped out. The Dealer replaced it with a Helicoil. (No Charge)

My question would be; I have come up several times with Aluminum against Steel. I question the AL against Steel.

The Helicoil is Steel, and it would seem to me that it could suffer the same fate as the orional oil plug - Unless something is done to stop this corrosion; such as putting it in with Epoxy or Permatex.

The Helicoil is Steel, the plug is said to be steel here I see not real problem; However would Anti-Sieze be a good idea? The engine oil may be enough.

From now on the Steel against Steel for the working surface should be no problem ?


Wish VW could be a little more comunicative about this.


I was looking into the Oil-tight Magnetic Plug. They have a rubberized washer. That washer could be a good idea in that it may not have to be torqued at tight as the copper washer.

The helicoil should be stainless steel and relativly impervious to even Boston chemicals. (I hear that Tea is Hell on Aluminum) The pan plug runs on the stainless, so I shouldn't be a problem. Anti-seze can be skipped since the threads are basically in oil all the time and purists may say that even that little bit of anti-seze in your engine oil is a bad thing.

The only problem I see possible is if the plug does sieze to the helicoil, it ay pull it out. That is typically only a problem when an impact gun is used, or so an engineer told me when he wasn't driving his choo-choo.

I say run it and if you change your own oil next time, try to have a spare helicoil on hand just in case you need it.