Tell us about yourself!
holey cow Batman I am a auto mechanic most of the taps I use are smaller than 1/2 inch 3 & 1/2 is huge now I may be wrong but dont the the (teeth) on the tap cut the (flute) on the work piece just sayin
If it was reground it will not have proper dimension and be rather pricy i would think
not that I know of sorry bro
Taps should only be driven by hand never with a power tool besides after rusting taps will lose the proper cuting edge
correct WD 40 is a solvent not a lubricant and is useful for more things than you could imagine but definitely not as a lube