Why helicoils suck

[Speeddog]

Some folks may have wondered why I don't recommend helicoils for repairing threads. 

This is why:




Not the first time I've seen this happen.

If it were something non-critical, I'd not be so pissed.
But it's one of the two posts that hold the front brake caliper onto the upright on my Dakota.
Some previous 'wrench' did a bush league repair.

[NorDog]

How do you feel about Time-Certs?

[Speeddog]

How do you feel about Time-Certs?

I love 'em. 

[ellingly]

Good. I can finally point my friends to a thread to show why I think helicoils are often the spawn of the devil. It's also why I used a time-sert in when I did a sump-plug repair.

But most people don't believe me and still stick with helicoils, even though the kits (least here in Aus) are about the same price.

[Speeddog]

Due to a number of factors, I replaced that Helicoil with another one. 

Can't have the truck off the road for the time necessary to get a Time-sert in my hands.
And, the helicoil thread is slightly larger than a Time-sert thread, so I need to consult with the Time-sert folks.

If they can confirm that it's close enough, I'll red loctite a Time-sert in.

Anyone need any M9x1.25 helicoils? 

[ellingly]

<James May>Cock</James May>

[Popeye the Sailor]

You know, I've used a number of helicoils over the years, and never had a problem.


Do we know if anyone competent here has used one and had issues?



Because, it's likely wahetever dumbmake the beast with two backs initially installed the one you found is some sort of, well, dumbmake the beast with two backs.

[booger]

dumbmake the beast with two backs or no the Time-Sert is a far superior thread repair

[scott_araujo]

I've used heli coils but not time certs, though I think from all that I've read that I'd go with a time cert if I needed a repair.

Something you can do to make the heli coil hold a little better...

Install the heli coil with super thread lock, the kind that needs heat and air tools to remove.  DO NOT install the bolt yet.  Let the thread lock set for say 24 hours or more before you install the bolt.  If the bolt doesn't need thread lock don't use it and use some grease or anti seize on it.  If it does need thread lock try to use one of the weaker varieties if you can.  All based on trying to get the heli coil to stick to the base more than it sticks to the fastener.

As Speeddog  says, sometimes you need to use a heli coil.  Hope this helps.

Scott

[aaronb]

looks like that heli-coil is a thread or two too short, and the bolt bottomed out on the tang (that's what she said)

[Langanobob]

You know, I've used a number of helicoils over the years, and never had a problem.


Do we know if anyone competent here has used one and had issues?



Because, it's likely wahetever dumbmake the beast with two backs initially installed the one you found is some sort of, well, dumbmake the beast with two backs.

Yeah, I think you is correct.  Not the easiest thing to do, but we're supposed to break the installation tang off after coil is in place.   If you look at the picture, the tang is still there and the bolt bottomed out on the tang, which in turn pulled the coils tight around the bolt like a Chinese finger-cuff.  So, when the bolt came out, it took the coil with it.

I personally  have never had a problem with a Heli-coil, but then I've never used a Time-sert to compare.  Looking at the Time-sert website, they come in either carbon steel or stainless steel.  For someone using stainless bolts on their Monster, a stainless threads on both bolt and insert can cause galling and seizing and I'd pick regular steel for an insert.  I think Heli-coils only come in stainless so that's something to keep in mind.

[Popeye the Sailor]

We use 'em on the satellites (really).





9 out of 10 rocket scientists agree they be fine 

[ducpainter]

We use 'em on the satellites (really).





9 out of 10 rocket scientists agree they be fine 

...and even though rocket scientists often walk in circles...

heli-coils work great...

Time serts given the perimeter clearance to work are a better solution in high torque applications.

But let's face it...

when all you have surrounding the threaded area is .125" or less a time sert isn't gonna work

[Langanobob]

...and even though rocket scientists often walk in circles...

heli-coils work great...

Time serts given the perimeter clearance to work are a better solution in high torque applications.

But let's face it...

when all you have surrounding the threaded area is .125" or less a time sert isn't gonna work

I remember from a previous epic Heli-Coil vsTime-Sert thread that Time-Serts require the same or even a smaller drill bit than Heli-Coils.  That was news to me.

[ducpainter]

I remember from a previous epic Heli-Coil vsTime-Sert thread that Time-Serts require the same or even a smaller drill bit than Heli-Coils.  That was news to me.

I just did some searching and find the hole size is actually the same.

I stand corrected.

I'll still use heli-coils...

I've never had an issue with them.