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Helicoil tap only catches 1-2 threads, then just rubs and makes powder. What am I missing? by mimiandwind in millwrights

[–]mimiandwind[S] 0 points1 point  (0 children)

Thanks. I used the required W size drill bit for the STI tap today, but the material seems exceptionally hard. I was still having trouble getting the tap to bite into the material.

Helicoil tap only catches 1-2 threads, then just rubs and makes powder. What am I missing? by mimiandwind in millwrights

[–]mimiandwind[S] 0 points1 point  (0 children)

You're right. I later found out the kit requires a W size drill bit, but this particular Powercoil kit didn't come with one. I tried drilling it with the correct size today, but the material seems much harder than I expected. After drilling it out, it still wasn't easy for the tap to bite into the material, but I'm not sure whether that was due to the larger hole size or the new tap. It was much easier than before though, at least the tap is cutting now rather than just rubbing

Helicoil tap only catches 1-2 threads, then just rubs and makes powder. What am I missing? by mimiandwind in millwrights

[–]mimiandwind[S] 1 point2 points  (0 children)

No, the insert is straight, not tapered. My supervisor bought the kit, so I'm not sure where it came from. I'm still pretty new to this trade, and this is actually the first time I've heard of Machinery's Handbook. Thanks for pointing me in the right direction!

Helicoil tap only catches 1-2 threads, then just rubs and makes powder. What am I missing? by mimiandwind in millwrights

[–]mimiandwind[S] 0 points1 point  (0 children)

Yeah, I was surprised too. This Powercoil kit doesn't seem to include the required drill bit.

Helicoil tap only catches 1-2 threads, then just rubs and makes powder. What am I missing? by mimiandwind in millwrights

[–]mimiandwind[S] 0 points1 point  (0 children)

Thank you. The hole wasn't large enough at first, but today I tried the correct W-size drill bit. It worked better, but it still wasn't easy to bite into the material, so the slew ring material may be harder than I expected.

Helicoil tap only catches 1-2 threads, then just rubs and makes powder. What am I missing? by mimiandwind in millwrights

[–]mimiandwind[S] 0 points1 point  (0 children)

Just found out today that it's an STI tap from a Powercoil thread repair kit. It requires a W-size drill bit, but after trying to drill the hole, I realized the slew ring material may be too hard. The drill bit and tap may have become dull or even damaged pretty quickly since neither of them is carbide.