[J S Machine]

I see a carbide three flute, TiAlN coated, 15 degree spiral treadmill on eBay. For about $75, I'm afraid to even buy it. Lol. I've never done any thread milling and I'm just afraid I'll break it.

[AUSTINMACHINING]

I see a carbide three flute, TiAlN coated, 15 degree spiral treadmill on eBay. For about $75, I'm afraid to even buy it. Lol. I've never done any thread milling and I'm just afraid I'll break it.

That's why you buy 3 of them :-). I do test cuts on aluminum starting with multiple step overs to dial in the tool path, then creep up to harder materials.Pay Attn to mfr recommended cutting parameters, and you should be ok. To look at these tiny tools for the first time, I was thinking "there's no way this could work". But they do. I drilled some .006" holes .25" deep. I couldn't even see the flutes on the drill bit !. Lol. Be aware that dropping the tool can snap the shank just under its own weight (no tool holder).I've done it. "Well sh#$#", there goes 50 bucks".

[CadRhino]

+1 seems like that skinny neck would snap but it doesn't.
Start with a slightly oversized hole and then see how tight you can thread with the next smaller hole, etc.

That's why you buy 3 of them :-). I do test cuts on aluminum starting with multiple step overs to dial in the tool path, then creep up to harder materials.Pay Attn to mfr recommended cutting parameters, and you should be ok. To look at these tiny tools for the first time, I was thinking "there's no way this could work". But they do. I drilled some .006" holes .25" deep. I couldn't even see the flutes on the drill bit !. Lol. Be aware that dropping the tool can snap the shank just under its own weight (no tool holder).I've done it. "Well sh#$#", there goes 50 bucks".