FWIW, I think that coolant makes a poor tapping fluid in tough materials. Sulferized cutting oil (or equivalent) seems to be very good. I even used SafeTap for a while, tapping A36, but the tap life was still not as good as sulferized cutting oil.
If your tap is chipping, it might indicate too high of a speed, too much heat is generated, and then the watery coolant shocks the tap and cracks the tips of the teeth. Another reason cutting oil is better is that it provides a less severe quench effect and lubricates much better than most coolants I have seen.
Hopefully your part setup allows the through moving chips room to evacuate.
It is true that some A36 plate is a bit harder. If you have a real troublesome batch, tapping in two steps might even be of some benefit. If you've hand tapped a few holes, you'll appreciate that 3/4" is a long way to drive a tap, when the lube oil is hand applied, because the tap is getting pretty dry by the time it gets to the bottom of the hole.
First you get good, then you get fast. Then grouchiness sets in.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)