Here's a pic of my crank gear sprocket puller setup, using the M8x1.25 tap-existing-holes method. Worked just fine. Thanks to the author of that idea. The gear is already partly pulled off. I used nuts to allow the bolt to remain fixed in the full thread of the hole, since the tap did not go exactly strasight and I only got about 7-8 full threads on it. It slid off pretty smoothly, at first one flat at a time.
Notice the busted off tang on the gear. I ground down the tips of a regular puller to fit, but that was the result.
NEWBIES NOTE: read up on tapping a thread before you start. I nearly snapped the tap off. Tapping must be done in stages, backed up each 1/4 turn or less to snap the preceding chip off. Use oil, get it as straight as possible, and remove it entirely afer each two full turns once you are into the full threads.