Turning a through-tap into a bottoming-tap

[LewisM]

Now, there is the usual way...bench grinder to remove the taper tip.

Or there's the Lewis Dumb way - trying to thread hard stainless with a $40 tap.

Snap.

Instant $40 bottoming tap. Ruined $9 stainless bracket (I am NOT going to try to turn the piece out, or alum it out)

And a multitude of cursing.

Lesson learned - more oil, back off to clear chips more often, and stainless is a royal PITA :P Ah well, i'll grind it flat now (but it's probably metallurgically effed now, except maybe in aluminium)

[brian nordstrom]

Lewis , we tap a lot of stainless at work and the best tap's for stainless are the ' Spiral Fluted ' style tap's and plenty of the 'RDT' ( reaming , drilling , tapping ) cutting fluid ( orange tube ) , the liquid one not the aerosol cans is the best .

Good luck and take your time as you said .

Brian.