12-27-2012, 05:22 PM
From: http://www.practicalmachinist.com/vb/gen...de-151027/. 4th post.
"Unless used in a very short blind hole, Normal taps essentially set out to cut a full depth thread with every tap, they just move it closer to the blind end with subsequent taps. If you don't have a blind hole, you need only use one tap.
The idea of serial taps is that the volumetric removal of the metal is spread over all three taps evenly, even for thru holes. This makes them excellent for hand tapping of difficult materials, like extreme work-hardening grades (hi-nickel alloys such as Monel, some grades of stainless steel, etc).
The individual taps do not work very hard. I have an SKF set I've owned for thirty years, they've tapped some horrible materials, and they're still every bit as good as new."
Must admit It's a new idea to me, never knew they've been around for so long.
"Unless used in a very short blind hole, Normal taps essentially set out to cut a full depth thread with every tap, they just move it closer to the blind end with subsequent taps. If you don't have a blind hole, you need only use one tap.
The idea of serial taps is that the volumetric removal of the metal is spread over all three taps evenly, even for thru holes. This makes them excellent for hand tapping of difficult materials, like extreme work-hardening grades (hi-nickel alloys such as Monel, some grades of stainless steel, etc).
The individual taps do not work very hard. I have an SKF set I've owned for thirty years, they've tapped some horrible materials, and they're still every bit as good as new."
Must admit It's a new idea to me, never knew they've been around for so long.
Arbalest, proud to be a member of MetalworkingFun since Sep 2012.