Thread forming (roll tapping) tips please

[Toolz_86]

Hi all,
I need to roll tap m3 x 9 deep in st/st 316. I'll be using a tin coated hss m3 thread forming tap and drilling 2.8mm. I cant afford to break one!

Any tips would be appreciated? Speeds for example? It will be done on a haas vertical milling cnc machine.
Thanks

[thedave]

Verify the you are using the correct drill size for the tap. (Check with the manufacturer) They usually different that the drill size for cutting taps. Fastest way to break forming taps.

[RICHARD ZASTROW]

Get serious with the tap lube. Forming taps extrude metal into form and consequently need good lubrication. But you knew that.LOL

Dick Z

[Delw]

Try emuge(sp)taps for 316 I believe they make a roll tap.
make sure you hole size is to the maximum minor dia before tapping.
even though its only 9mm deep you may have to peck tap it twice.