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Stem & Crank Thread Repair (Heli-Coils)

#1 2010-12-30 6:25pm

xtremevert
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Stem & Crank Thread Repair (Heli-Coils)

Over the holidays I decided to change my handlebars on my GT and one of the stem bolt threads blew out.  So I thought maybe I should buy a new stem but then remebered from my past experience working in oilfield repairing pumps and injectors that we used to use Heli-Coils to repair threads on damaged pump bodies.  So I went to the local nut and bolt supply store and picked up a Heli-Coil repair kit.

For those of you not familiar with Heli-Coils they are a threaded insert that (if done properly) can effectively fix that much needed part for your build.  I decided to share the work I did today so people can see first hand how to fix blown out stem or crank threads.  Those are the only 2 parts I think of first hand that you could repair with a kit like this but maybe there are more.

So first you need to take your bolt to the nut and bolt store and get them to match up the thread to the proper repair needed for the repair.  They matched it up and this is what I got.  The only downfall is that it cost me $40 CND (I got a $10 discount because I have an account) so they normally run $50 CND fo the average off the street customer.  It was kind of a toss up between the kit and just buying a new stem. 

http://i263.photobucket.com/albums/ii149/xtremevert/HeliCoilStem005.jpg

You will also need a drill index because the kit does not come with the drill bit required to do the job.  For that kind of money you think it would.  This particular 8mm bolt repair kit required a 21/64`` drill bit.

http://i263.photobucket.com/albums/ii149/xtremevert/HeliCoilStem001.jpg

First you need to drill out the hole.  Make certain you do it squared up and straight with the existing hole.  This makes a huge difference when you have to tap the hole.

http://i263.photobucket.com/albums/ii149/xtremevert/HeliCoilStem011.jpg

Next you need to clean out all the shavings and prep it for the tapping required to insert the Heli-Coil.


http://i263.photobucket.com/albums/ii149/xtremevert/HeliCoilStem012.jpg

http://i263.photobucket.com/albums/ii149/xtremevert/HeliCoilStem013.jpg

http://i263.photobucket.com/albums/ii149/xtremevert/HeliCoilStem014.jpg

Next you are going to tap the hole with the tap provided in the kit.  I used some tapping oil to make it a little easier not only for the tapping but also it keeps your tap threads in good shape.

http://i263.photobucket.com/albums/ii149/xtremevert/HeliCoilStem015.jpg

http://i263.photobucket.com/albums/ii149/xtremevert/HeliCoilStem016.jpg

Next I used a light weight autobody hammer to set the tap into the hole.  Make sure it`s good and straight!  This is very important otherwise you stem cap won`t go back on properly and you might have to enlarge the stem cap hole because of a badly angled insert.  yikes


http://i263.photobucket.com/albums/ii149/xtremevert/HeliCoilStem018.jpg

Next make your thread by using the tap provided and a tapping tool wrench that comes with a tap and die set or you can use a crescent wrench like I used.  I prefer using the crescent wrench.  smile

http://i263.photobucket.com/albums/ii149/xtremevert/HeliCoilStem020.jpg

http://i263.photobucket.com/albums/ii149/xtremevert/HeliCoilStem021.jpg

Make sure you bottom out the tap into the bottom of the hole to ensure a proper thread tap.

http://i263.photobucket.com/albums/ii149/xtremevert/HeliCoilStem024.jpg

After that`s done clean the hole again and re-thread the tap one more time for good measure.  smile

Next thread on a Heli-Coil to the Heli-Coil insert tool provided with the kit.

http://i263.photobucket.com/albums/ii149/xtremevert/HeliCoilStem029.jpg

Then insert the Heli-Coil into the freshly tapped threads.

http://i263.photobucket.com/albums/ii149/xtremevert/HeliCoilStem030.jpg

You want to insert the Heli-Coil 2 threads below the threads you just tapped.

http://i263.photobucket.com/albums/ii149/xtremevert/HeliCoilStem031.jpg

Once you are done there is a small tine that needs to be removed on the bottom of the insert.  I used a hammer and punch to knock it off the end of the insert and then blew it out of the hole with the air gun.  If you don`t remove it your bolt will not screw all of the way in and will stop at the tine.  The tine at the bottom of the insert serves as a stopper so you can actually thread the insert properly without the insertion tool passing through all of the threads.

Once it is done it should look like this.


http://i263.photobucket.com/albums/ii149/xtremevert/HeliCoilStem033.jpg

I used a heat gun after to cure the blue thread locker I used to permanetly set the insert in place.  This is an optional step.  I only did it so the insert would never come out by mistake.  In the past I`ve had threaded inserts back off when removing the bolt (I think it happened once in all my years) and I did this to prevent that from possibly happening.

http://i263.photobucket.com/albums/ii149/xtremevert/HeliCoilStem034.jpg

So there you have it.  I documented this thread in hopes that it might be able to help out some other members who have encountered the same problem.  It worked out great and the thread is good as new and I saved myself the headache of having to hunt for a new stem.  smile

http://i263.photobucket.com/albums/ii149/xtremevert/HeliCoilStem036.jpg

http://i263.photobucket.com/albums/ii149/xtremevert/HeliCoilStem035.jpg

Last edited by xtremevert (2010-12-30 6:34pm)


My Father once spoke to me and said "The way you look at your bike is the way I see My children, I look past the imperfections and rough surfaces to the beauty of the finished product."

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#2 2010-12-30 7:09pm

79mongoose
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Re: Stem & Crank Thread Repair (Heli-Coils)

thats pretty sweet!!big_smile


When it comes to math, there's 3 kinds of people in the world:
Those that can count and those that can't

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#3 2010-12-31 6:03am

jlewis
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Re: Stem & Crank Thread Repair (Heli-Coils)

Very cool.  Thanks for posting!  cool

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#4 2011-03-21 12:24pm

mongoosefreak
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Re: Stem & Crank Thread Repair (Heli-Coils)

Very Nice Job. That Bike looks Sweet...cool

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#5 2011-03-21 12:34pm

Swift
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Re: Stem & Crank Thread Repair (Heli-Coils)

Go for time-serts over heli coil if you can, yes they are more expensive, but more stable

http://www.timesert.com/

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#6 2011-03-21 12:41pm

manida
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Re: Stem & Crank Thread Repair (Heli-Coils)

I'd surely eff this project up.....


Im in this hobby for the nostalgia.  Most of my bikes are ongoing projects.
My day-to-day riding consists of commuting, bar-hopping and mountain biking.

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#7 2011-03-21 9:40pm

xtremevert
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Re: Stem & Crank Thread Repair (Heli-Coils)

Swift wrote:

Go for time-serts over heli coil if you can, yes they are more expensive, but more stable

http://www.timesert.com/

yup , those are cool.  how much are those per sert?


My Father once spoke to me and said "The way you look at your bike is the way I see My children, I look past the imperfections and rough surfaces to the beauty of the finished product."

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#8 2011-04-01 8:21pm

Swift
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Re: Stem & Crank Thread Repair (Heli-Coils)

Here is the same size kit that you used in time-sert. This amazon price is 54.99, so a good bit more than heli coil.

http://www.amazon.com/TIME-SERT-Metric- … B001JK44LG

I found these when one of bolt holes that was helicoiled for a camshaft cap bolt stripped out of the head in my motorcycle. Perhaps it was just too much for heli coil in the aluminum at 120 inch/lbs, I am not sure, or it could have been the repeated abuse.
I just want to make sure everyone know that I am not saying that helicoils are bad.

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#9 2011-04-01 8:28pm

79mongoose
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Re: Stem & Crank Thread Repair (Heli-Coils)

lilbike wrote:

thats too much work

only 18 posts, no feedback, and banned already? lol


When it comes to math, there's 3 kinds of people in the world:
Those that can count and those that can't

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#10 2011-04-01 11:29pm

xtremevert
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Re: Stem & Crank Thread Repair (Heli-Coils)

79mongoose wrote:

lilbike wrote:

thats too much work

only 18 posts, no feedback, and banned already? lol

that is funny!  lol


My Father once spoke to me and said "The way you look at your bike is the way I see My children, I look past the imperfections and rough surfaces to the beauty of the finished product."

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#11 2011-04-21 8:17pm

1koolripper
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Re: Stem & Crank Thread Repair (Heli-Coils)

Thank you for the info. Great step by step pics also. Where were you 25 yrs ago when this happened to me.lol Thanks again for the great info.cool

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#12 2011-04-22 11:27am

t2jeff
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Re: Stem & Crank Thread Repair (Heli-Coils)

You should use the proper tap holder instead of a wrench. Holding the tap on one side (the wrench handle) instead of of using both sides of a tap wrench promotes the tap going in off center. Looks like yours came out clean, but for 1st timers, the correct tools can only help.
Nice photo documentation to tell your story!!!


Looking for a Sugino 400 dust cap!!!! Help!

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#13 2011-04-22 10:51pm

79mongoose
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Re: Stem & Crank Thread Repair (Heli-Coils)

t2jeff wrote:

You should use the proper tap holder instead of a wrench. Holding the tap on one side (the wrench handle) instead of of using both sides of a tap wrench promotes the tap going in off center. Looks like yours came out clean, but for 1st timers, the correct tools can only help.
Nice photo documentation to tell your story!!!

i had that same thought too.


When it comes to math, there's 3 kinds of people in the world:
Those that can count and those that can't

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#14 2011-04-22 10:55pm

Dirty Habits
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Re: Stem & Crank Thread Repair (Heli-Coils)

cool


[img]https://i.postimg.cc/pXMBPm4q/dirty-tequila-logo.jpg[/img]
I asked God for a bike, but I know God doesn't work that way. So I stole a bike and asked for forgiveness............-Emo Philips

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#15 2011-04-22 11:00pm

tcbmx
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Re: Stem & Crank Thread Repair (Heli-Coils)

cool


What's the point of having a bike if you're not going to ride it?

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#16 2011-04-26 2:14pm

xtremevert
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Re: Stem & Crank Thread Repair (Heli-Coils)

t2jeff wrote:

You should use the proper tap holder instead of a wrench. Holding the tap on one side (the wrench handle) instead of of using both sides of a tap wrench promotes the tap going in off center. Looks like yours came out clean, but for 1st timers, the correct tools can only help.
Nice photo documentation to tell your story!!!

yeah I guess I never thought of the "first timer" who is going to try it.  I've done it a thousand times over and never thought of it.  Good point.  anyone want to post a pick of the actual tool used?  smile

Last edited by xtremevert (2011-04-26 2:17pm)


My Father once spoke to me and said "The way you look at your bike is the way I see My children, I look past the imperfections and rough surfaces to the beauty of the finished product."

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#17 2011-06-07 2:05pm

clubautio
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From: Maple Grove, MN
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Re: Stem & Crank Thread Repair (Heli-Coils)

Well done sir!

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#18 2011-06-14 9:06pm

ultrahots
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Re: Stem & Crank Thread Repair (Heli-Coils)

Very Nice pics and presentation.The Heli Coil kit you used is the best I have found so far.The issue with Time Serts is they cannot be flush mounted as the insert sticks up above the thread surface where as you have shown the Heli coil can be run down an extra thread or so.I normally put the insert in with Thread Locker or Loc Tite on it already and then use a product such as anti seize on the bolt.


P.S. Nice Ride !

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#19 2011-06-22 7:53am

josh2mic
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From: australia
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Re: Stem & Crank Thread Repair (Heli-Coils)

smile
thanks for posting that pic..

love it
smile

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#20 2011-06-22 7:59am

chromey
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Re: Stem & Crank Thread Repair (Heli-Coils)

Sweet thread Jason!


(no pun intended. tongue )


— — — — —
"every move is like a lightning..."

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#21 2011-06-24 11:34am

hoolian23
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Re: Stem & Crank Thread Repair (Heli-Coils)

that looks like alot of work but its cool and that bike is sick !!!!!!!


famous last words: Is it bleeding, whats the worst that can happen, that's just a small jump

Pain is temporary quitting lasts forever

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#22 2011-09-08 5:41pm

zehlersan
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From: Houston, TX
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Re: Stem & Crank Thread Repair (Heli-Coils)

nice to know this thanks man smile


smile

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#23 2013-10-20 10:07pm

Backinthesaddle44
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From: Lower Slower DE
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Re: Stem & Crank Thread Repair (Heli-Coils)

I just used this thing on my 302, plug dropped down and i repaired it with the heli coil kit. Who knew i could use it for something else ? Worked great putting that plug in.
smile


We are paid by those who learn by our mistakes ~ The Working Hour

Be kind, for everyone you meet is fighting a hard battle - Plato

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