i finally got around to regrinding a collection of dull center punches. i had no idea they would give me so much trouble. they all have octagonal shanks, i have four sizes, 3-5 of each. how to hold them on the tool grinder? i need either square deckel collets (6mm, 8mm etc.) or er collets in 13 (for 12.75), 11 (for 10.75) and 8.5 mm. i have neither of those. so just for fun i made a split bushing, 12,75/16mm for the deckel collet and the second problem occured: runout of around 0.5mm. i ground one punch and it was ugly to look at. i ended up shimming the bushing with tape in two places and got a punch down to 0.04mm. the next one of course was different so i got tired of it. id either have to make 4 excentric bushings, buy collets worth more than the punches or get some independent four jaw for grinding (morse or deckel u29). does such a critter exist? and how do they grind the punches when they are made anyway?
so any ideas how to do this seemingly simple job without to much effort?
so any ideas how to do this seemingly simple job without to much effort?
