Tapping stainless?

[hanau]

Needing to tap 8-32 screw into stainless steel 304.
any recommendation of taps that don't break easy when hand tapping.
drill the holes out to #29 drill bit and have broken 2 Irwin taps.

Looking for a quality tap that doesn't break easy.

 

[Paul in OKC]

Are you hand tapping or machine tapping? Also are you using plug, taper or bottom taps. Blind hole or through hole.

 

[jttheclockman]

It is not so much the tap as it is the lubricant used. This is what I have found to be the best I ever used. Worked in an industrial plant where we had to drill cut and tap a lot of stainless steel in various thicknesses and this is what we used.

Ordinary tool taps and drill bits.

Protect All Industrial Tapping & Threading Compounds Page

 

[mredburn]

Also are you using a High speed steel tap or a carbon steel tap?

 

[hanau]

The taps i was using where high carbon plug taps. Doing a through hole by hand using rapid tap fluid.

I was told to try going up from a #29 to a #27 drill bit.
Works good and screw tighten up just fine.

 

[Paul in OKC]

Tapping fluid is good. Carbon taps are not for making new threads, unless tapping butter . Carbon taps are best used to fix something already threaded. For through holes I like tapered taps, or called gun taps. They push the chips out the bottom of the hole.

 

[hanau]

Thanks paul does 2,3,4 flute make much different?

 

[Paul in OKC]

It does. In my previous post I meant to say spiral point, not tapered. On smaller taps I prefer 2 flute. They seem to be a bit stronger. Your advice about going larger is something that works at times as well, as long as it is not too much.

 

[lwalper]

Stainless 304 isn't really that tough -- kinda soft actually. Make sure you're going in straight - and use something other than a plug tap - they don't start very well - easy to get crooked and bind / break.

 

[manleymaille]

on any stainless i use molly-d lubricant but that is just my 2 cents and i also prefer spiral flute taps again just my two cents

 

[Paul in OKC]

If drilling the parts on a drill press, you can use it to tap. Put the tap in the chuck and rotate by hand while feeding the quill. Once the tap is started it will feed itself down. Good way to keep things straight.