Broken exhaust stud removal

[JHZR2]

And I now feel like a total idiot. Please tell me there is a way to remove a helicoil?? I didn’t snap off the tang. This one I gently threaded in but it will not come out.

Fortunately it’s not the blind hole but this is ridiculous.

 

[Pablo]

There is a removal tool

 

[JHZR2]

There is a removal tool

Is it going to be as lousy as the other things getting that are all horrible??!? lol!!

I was able to feed it forward and out since it was the non-blind hole…


Beyond frustrated with all of this.

 

[Pablo]

Is it going to be as lousy as the other things getting that are all horrible??!? lol!!

I was able to feed it forward and out since it was the non-blind hole…


Beyond frustrated with all of this.

What is the issue?

 

[JHZR2]

What is the issue?

I didn’t know I couldn’t back out a Helicoil once it was started.

But my bottom tap, US made, Helicoil branded, picked up in person from McMaster-Carr, has a different thread than the other taps of the same M8x1.25 STI designation!!

Two kit taps:

M8x1.25 STI bottoming tap (right) vs m8x1.25 STI tap (left) used to cut the threads (which helicoils obviously thread into since I did it and got one stuck):

 

[Pablo]

I didn’t know I couldn’t back out a Helicoil once it was started.

But my bottom tap, US made, Helicoil branded, picked up in person from McMaster-Carr, has a different thread than the other taps of the same M8x1.25 STI designation!!

Two kit taps:



M8x1.25 STI bottoming tap (right) vs m8x1.25 STI tap (left) used to cut the threads (which helicoils obviously thread into since I did it and got one stuck):

Wow.........which is correct?
Almost but maybe not looks like the one on the left is M8x1.0

 

[JHZR2]

Wow.........which is correct?
Almost but maybe not looks like the one on the left is M8x1.0

That was my initial thought as well. But it isn’t as it doesn’t fit the 1.0 pitch gauge. Which could marginally make sense if it was an 8x1.0 STI. But lots definitely labeled 8x1.25 STI.

Going back to McMaster….

 

[Pablo]

That was my initial thought as well. But it isn’t as it doesn’t fit the 1.0 pitch gauge. Which could marginally make sense if it was an 8x1.0 STI. But lots definitely labeled 8x1.25 STI.

Going back to McMaster….

You are completely screwed now, no?

 

[The_Jeff]

Does the desired fastener thread in to that mess?

If it were my ride, I'd snap that off flush and rock the three threads of engagement, gingerly torquing of course. Not because it's right, but because I was done.

 

[JHZR2]

You are completely screwed now, no?

??? How so, or is that a pun?

I wanted a bottoming tap to get a few more threads in the blind hole. Don’t need it in the through hole.

It just doesn’t thread. Standing at McMaster will call now. Didn’t bring the other but I think it will be obvious when I open it up…

Might even ask them to pull another 8x1.25 STI bottoming if they’re willing.

 

[JHZR2]

Does the desired fastener thread in to that mess?

If it were my ride, I'd snap that off flush and rock the three threads of engagement, gingerly torquing of course. Not because it's right, but because I was done.

The belmetric M8x1.25 studs thread in fine.

It’s part of the stupid tax. I assumed that I could thread in a helicoil, not break the tab, and then thread it out, sort of a test fit. Obviously you can’t.

Good thing I did it in the through hole so I could ultimately thread it out the bottom. But ugh, just another annoyance.

Part of the why is because I’m going to smooth the surface to flat as there was some erosion and that’s where diesel fumes were escaping. So I’m going to remove some material and want the helicoil below that new surface.

 

[JHZR2]

You are completely screwed now, no?

Of course I didn’t bring the other one to compare but the thread pitch seems slightly bigger(?).

I wonder if I can center drill these to use my setup with the spring loaded pin in the future. Don’t need a big hole.

 

[Pablo]

??? How so, or is that a pun?

I wanted a bottoming tap to get a few more threads in the blind hole. Don’t need it in the through hole.

It just doesn’t thread. Standing at McMaster will call now. Didn’t bring the other but I think it will be obvious when I open it up…

Might even ask them to pull another 8x1.25 STI bottoming if they’re willing.

No I just wasn't following. Sorry. I thought there was a non-match with actual helical insert.

View attachment 346078
Of course I didn’t bring the other one to compare but the thread pitch seems slightly bigger(?).

I wonder if I can center drill these to use my setup with the spring loaded pin in the future. Don’t need a big hole.

I keep getting confused. I THOUGHT you are getting a bottoming tap???

 

[JHZR2]

No I just wasn't following. Sorry. I thought there was a non-match with actual helical insert.

I keep getting confused. I THOUGHT you are getting a bottoming tap???

I bought the bottoming tap yesterday. That’s one one with the funky thread.

The bottoming tap won’t thread into the threads I cut. See my thread on tool time for more photos.

So I went and got an official USA made helicoil plug chamfer tap to compare. I’m trying to determine if Helicoil USA made STI taps actually have a different pitch, or if the bottoming tap I bought is defective.

 

[JHZR2]

Whaddaya know??!?

The plug chamfer white box USA made Helicoil tap threaded in by fingers perfectly.

So what exactly is the 8x1.25 STI bottoming tap??!?

Back to McMaster I’ll go later.

 

[Pablo]

Threaded in by fingers perfectly.

Which one? Not specific.

 

[D60]

I wonder if I can center drill these to use my setup with the spring loaded pin in the future. Don’t need a big hole.

You could just order the inexpensive tap wrench set I linked. For me it's invaluable when taps aren't center drilled.

That said, they do eat up a lot more Z space and since your DP doesn't have a knee, this could be a problem at times.

I've never tried to drill a tap but I don't foresee great results. edit: except broken taps and that doesn't work with HSS or cobalt

 

[JHZR2]

Which one? Not specific.

The USA made white box plug chamfer Helicoil tap that I just got from McMaster this am.

Which validates that the blue box labeled M8x1.25 STI bottoming USA made Helicoil tap is wrong somehow.

I wasn’t dreaming or using my pitch gauge wrong.

 

[Pablo]

Bingo!

The USA made white box plug chamfer Helicoil tap that I just got from McMaster this am.

Which validates that the blue box labeled M8x1.25 STI bottoming USA made Helicoil tap is wrong somehow.

I wasn’t dreaming or using my pitch gauge wrong.

Junk tap!!

 

[JHZR2]

Bingo!

But this wasn’t the Chinese junk tap that didn’t fit. This was another USA made tap labeled correctly but threaded wrong.

Can’t make this up!