Broken exhaust stud removal

[JHZR2]

I have done less set up and did fine

Not a criticism- if the two imaginary cylinders are parallel within a reasonable amount you will be fine

If the hole is not perpendicular with the plane created with your set up something will give- the tap will follow the hole hopefully

I actually can’t get the tap started at all in either hole. Brand new tap from Helicoil. Won’t go in either.

It’s tapered.

 

[QwikKota]

That looks like a plug tap. That is what I use 90% of the time but if it won't start threading in you may need a full taper tap.

Also, if your drill press has .008" runout I doubt anything new would be a whole lot better unless you spent a ton of money for something made in Europe or USA.

 

[JHZR2]

That looks like a plug tap. That is what I use 90% of the time but if it won't start threading in you may need a full taper tap.

Also, if your drill press has .008" runout I doubt anything new would be a whole lot better unless you spent a ton of money for something made in Europe or USA.

I’m using the tap that came in the Helicoil kit.

It won’t go. At all. Either hole…

 

[Pablo]

I’m using the tap that came in the Helicoil kit.

It won’t go. At all. Either hole…

Hole measuring ok?

 

[JHZR2]

Hole measuring ok?

Hole required 21/64”. 21/64=0.328

Holes are:

Bit is:

So all very good, I think?

 

[Pablo]

Diameter of tap start?

 

[JHZR2]

Diameter of tap start?

 

[Pablo]

I’m watching soccer so my Machinery handbook not near. Is that nominal OD?

 

[JHZR2]

I’m watching soccer so my Machinery handbook not near. Is that nominal OD?

Which? I just measure what I can…

 

[Pablo]

Which? I just measure what I can…

The tap itself

 

[JHZR2]

The tap itself

I measured the flatter section of the threads and then the fully formed ones higher up.

 

[Pablo]

I measured the flatter section of the threads and then the fully formed ones higher up.

I’m trying to ask if the tap itself is within specification

 

[JHZR2]

I’m trying to ask if the tap itself is within specification

Sorry I don’t really know how to tell that. ELI5.

I don’t truly know what the Helicoil outer thread is or how to determine it. Could the tap be wrong? I’ll have my wife pic up a parts store kit to compare.

 

[Pablo]

Sorry I don’t really know how to tell that. ELI5.

I don’t truly know what the Helicoil outer thread is or how to determine it. Could the tap be wrong? I’ll have my wife pic up a parts store kit to compare.

I don’t think it is but doubt everything

Maybe now we know about a generous countersink

 

[Trav]

Try using a bit more downward pressure, the tap is not just going to catch without it, use cutting fluid.

 

[JHZR2]

I don’t think it is but doubt everything

Maybe now we know about a generous countersink

I could put more countersink if that would help.

Try using a bit more downward pressure, the tap is not just going to catch without it, use cutting fluid.

I’m not light and I’ve pushed pretty hard. I am still doing it on my drill press table though.

Even chucked it in the drill press to attempt to get more downward pressure while I have turned it. No dice.

Will try to put on a hard surface, shim level, and push harder…

 

[JHZR2]

Try using a bit more downward pressure, the tap is not just going to catch without it, use cutting fluid.

I put it on the floor so I could lean into it. First lightly, then harder.

I think I ruined the tap doing that when I put weight and force on it.

I also added a bit more chamfer tot he hole. Still no luck.

It just won’t go, and if it did, no way to get it straight with the force I’m putting on it.

 

[JHZR2]

I’m trying to ask if the tap itself is within specification

Is this what you mean?

 

[paulo57509]

Ignoramus thinking out loud....Would a tapered hole help the tap get a bite? Not tapered the entire length, just the first three or four threads? Tapered reamer?

 

[D60]

Is the tap labeled as M8x1.25 STI?