Installing a thread insert

[Desmo]

"Do it up until it goes loose, then back it off half a turn"

I think all of these kits are pretty much the same regardless of which manufacturer you buy it from, but the most common kit is a "Helicoil" kit.
The one I have is a "Recoil" kit from Alcoa fasteners. This is an M6 kit and comes with a drill bit, a tap, an insertion tool and a tang break off tool as well as an assortment of M6 inserts in varying lengths.

It doesn't come with a tap handle, so I had to make do with a spanner.
The inserts are stainless, so they will always be stronger, and last significantly longer than the cast aluminium that most of our engine cases are made from.

Let's say this old cylinder head has a stripped thread.


*
Take the fastener from your workpiece and one of the thread inserts and check you do indeed have a matching thread.


First start by taking the drill bit and drilling out the old thread, and making way for the tap to be run down it.
Ideally, this would be done with a pillar drill whilst holding the workpiece perfectly level and straight. I had to make do with my eye.



Here's the tap, I like to use cutting oil, although it probably doesn't matter too much with aluminium.



Start the tap by hand, making sure it's true.


When you start tapping, do about 2 turns at a time, then back it out to clean out the swarf.


Here's the newly tapped hole, make sure you clean out all the swarf.


The insertion tool has a movable collar so you can get the depth setting right.
Slide the thread insert over the tool and line up the tang with the slot in the tool.



*
Wind the thread insert with a slight downward pressure into the workpiece. The inserts are marginally larger than the thread you just tapped so they take a little bit of effort to start, once they are in and the tool is removed, they spring back out, effectively locking the insert in tight.


*
When the collar is flush, wind it 1/4 to 1/2 a turn more to ensure the insert isn't inserted too far in, check a few times to be sure, it only needs to be 1/4 to 1/2 a turn inside.


Take the tang break off tool and insert it up to the tang, give the end a sharp tap with a hammer and the tang will break off.
You don't have to remove the broken off part but I like to.



*
Here's the completed item. I actually wound the insert in too far on this one as you can see, but it is still better than the old, wrecked thread.

[Satan1]

Nice write up mate.

[rharris]

thank you for that where did you buy the kit cheers

[Desmo]

I actually got it from the local Auto-pro up here.
The guy loves the bike and is going out of his way to source tools etc. I may be paying a little over the odds, but I'd rather the money stays in town.
The kits range from about $50 upwards, this one was about $70 but I got 36 inserts with it.
Enough to do all of the cases on the 748.
I should imagine Coventry's or Atom would stock them.
You can get an M6 powercoil kit from Collins for about $50 IIRC.
Collins Industrial Distributors

[chee]

nice one jim

[g0zer]

cool, ive never seen a heli coil before

[monsta]

did ya do that on the kitchen bench? rental is it?


good write up...

[Desmo]

Lol, nah, outdoor table.

[MattstaZX10r]

No 1 MUST HAVE for older Jap bikes in 6mm .. Good Thread DG..

Helicoil kits used to be the better ones but think all pretty much same same now..

[Desmo]

First post edited, edits and editions denoted by a *.

How durable would these be over standard?
I'm thinking more thread in the aluminium=greater surface area + stainless threads would make for a much better than factory job.

[chew]

First post edited, edits and editions denoted by a *.

How durable would these be over standard?
I'm thinking more thread in the aluminium=greater surface area + stainless threads would make for a much better than factory job.

I have used them on Airconditioning compressor head bolts, Ducatis and everything in between. Have never had an issue with them when installed as per instructions.

[Desmo]

I have a few stripped threads on the Duc engine cases, and I'm seriously considering just doing the lot.

[chew]

Do you have a tension wrench? Or is it previous ham fisters efforts? (maybe poor use of phrase on this site).

Personally I would inspect them and only replace those that look stretched or have actual damage. I am from the "If it aint broke, dont fix it" school.

[Desmo]

Yeah, it's from the motor being apart so many times I think, worn threads, previous hamfistedness etc.

[Viper]

I had to use these when putting my spools on the swingarm for the stands.

Kwaka in their wisdom use some fkn random thread size so I converted it to 10mm I think it was.

[Mockery]

Thanks for this thread, Jim.
I'm familiar with Helicoils but always wondered just how they are installed... now I know.

[BigTim]

Nice write-up, dude.
One thing I like to do with helicoils is Loctite them in place, so you can be fairly certain you'll always be removing just the bolt, and not the thread insert too. 272 is more than enough.

Oh, and I'm with chew, as far as the other threads go. If they're still intact, it's not worth stuffing with.

[Desmo]

Just do them as they strip

Thanks for this thread, Jim.
I'm familiar with Helicoils but always wondered just how they are installed... now I know.

Expect a lot more write ups in the future as I do the Duc.
I'll update the build thread, then link to a how-to of how it's done if I think it'll be useful or interesting to others.

[Satan1]

I'm bored in exmouth

Least we get to benefit

[Desmo]

Reading up, a helicoil repair is about twice as strong as the original which is good.
These are interesting, positive locking steel inserts, would be good for head bolt repairs, main bearing etc.
++ TIME-SERT Metric Kits ++ thread repair kits and inserts repair stripped threads damaged threads repaired threads threaded inserts for metal thread inserts for metal aluminum inserts threaded inserts for aluminum