[Peter Gibbs]

Hey Geoff, I am breaking taps after 10 cycles can you help... I am drilling M5.2 hole 18mm deep, in 304 SS and tapping 6 X1mm 12mm deep @ 300rpm using a spiral flute tap designed for SS... so i reverted to a gun nose tap which pushes the swrarf down the blind hole ( thats why I have drilled it deeper ) and have done 60 cycles with out breaking the tap any clues mate. cheers peter

[Geof]

Not many, I (we) do not tap stainless.

I can say that your experience with the gun nose tap versus the spiral flute matches mine in steel; the spiral flute is not as strong so it does not last as long as it gets dull.

Perhaps other people more involved in tapping stainless will have suggestions.

[WOLOG]

Peter,

Send Andre at Emuge an email about what is going on. This guy knows taps.

Have you checked your SFM based on the material and the tap? If your RPM's are too slow, snap! Especially on a smallish tap.

[Peter Gibbs]

Gentlemen thanks Peter

[rbest27]

roll taps!

[AbsoluteZero]

Always roll taps in S.S. No chips no more problems and they are the strongest due to the no flute factor.

[AMCTony]

ROLL TAP!!! This would be great in 304 especially due to the fact that it is gummy and ductile. The threads will also be much better quality and less likely to gall.

[rbest27]

Only problem with roll taps is when they break you aren't getting them out. But I use them as much as possible. You get a better stronger thread, and you usually get really good use out of them. I would also suggest using a tapping fluid designed for stainless. There is some white thick tapping fluid out there, we call it what it looks like, but I know there's some out there. MolyDee always works well too, just stinks.