11-21-2015, 11:29 AM
Just to carry on from Ken (PixMan) - When metric threads became standard (in Europe) it was decided that the 1st or taper taper tap would have a longer and different (angle) taper than the imperial taps (BSF / Whit). The idea being if one uses the correct drill for the hole then the taper tap because of it's taper will tend to go in square with out too much trouble. Well that was the idea.
If I am taping a hole on the bench I will always start with the taper tap and then either the second or bottoming tap depending on how I feel
If I start the taping on a machine (lathe or mill) I nearly always use the second tap because the machine will keep it square.
On a blind hole I always use all three taps especially on taps 6mm and under using all three taps allows for a gradual removal of material by each tap and doesn't put undue force on one tap.
DaveH
If I am taping a hole on the bench I will always start with the taper tap and then either the second or bottoming tap depending on how I feel
If I start the taping on a machine (lathe or mill) I nearly always use the second tap because the machine will keep it square.
On a blind hole I always use all three taps especially on taps 6mm and under using all three taps allows for a gradual removal of material by each tap and doesn't put undue force on one tap.
DaveH
a child of the 60's and 50's and a bit of the 40's