Thanks John, sorry to be slow replying! I wonder just how easy it would be to monitor the current on our mills, a clamp type meter would be simple?

Pat

Quote Originally Posted by John S View Post
Monitor the spindle motor amperage, if it goes up you have a chipped or blunted tool, simples.

Also change to 4 facet ground drills, they last far longer before the web degrades.
I do roughly the same job 1,000's of 2.5mm to 3mm holes in 4mm and 6mm steel, not stainless so i use cobalt drills as they are more forgiving.