Saturday, February 11, 2017

How Many Different Types of Taps Are There? And Why Do You Pick One Over Another?

Spiral flute taps channel debris upward, which matters a lot on soft materials like aluminum and acetal.  Changing to such dramatically improved shop productivity today.  My experiment using a 6" long drill bit to drill both sides of these square tubes in one operation was a great success.  The pilot holes only need marking by the mill on two of four sides.  I will I could find a drill/tap combo with enough length to do both sides at once.  For some reason, you get such for 1/4"-20 just long enough for one hole at a time.


  1. If you don't need the threads to be aligned, meaning that one long threaded piece needs to go through both holes, you can use a pulley tap which has a longer shank and can tap both sides in one pass.

  2. has 6" long 1/4 20 spiral flute taps.

    Probably longer ones to but I am on my phone at the moment