Which tap??

[njhussey]

Ok so what's the score with coarse v fine ? Which category does a standard metric bolt sit in?!

Also can you hand tap with a spiral point?

I believe the standard preferred metric screw thread is the coarse thread. Fine is generally used when wall thickness is less than you'd ideally like.

No idea about the spiral tap, I'd guess tho that it's mostly for drilling with a hand drill. I put my tap in a cordless drill when I had 48 M8 holes to tap when I was doing some bits for my early design (which has since been scrapped)