I had some code to cut a 2" circle inside a subroutine. The subroutine is called many times with a -Z feed before each time to eventually cut throuhg the plate leaving a 2" hole. I paused the program to clear chips using the "feed hold" button. When I pressed the "cycle start" button to get it going again the X&Y feeds took off heading somewhere and crashed the tool into the side of the hole. I can only assume it jumped out of the subroutine (and even the whole loop) and was heading home or to the next operation on the plate.
 Luckily it's a mill drill. The head was rotated around by the force and the part only slightly damaged. The tool is fine. A lot can happen by the time you get to the E-stop.
 In any case this begs the question - when is it safe to use the feed hold button? I've avoided it since.

Sage

Think there may be problems using feedhold in subs.
Brian is working on a new version that should sort out problems, not sure if subs will be sorted or not but think there are other problems with feedhold. Never seen them myself but occasionally there have been reports.

Hood