up to 10mm dowel no problem Michael. Hexadecimal? ?hexagonal. maximum length of each cut is 150mm.
the pics show a 262mm long spar cut from 8mm dowel with an octagon center section. not totally finished. center section needs end bevels.
I used the CNC Mini Mill to make the 26 spars for the Mamoli USS Constitution. The first one took a couple of hours, while I was getting used to the settings, the material, the feed rates and spindle speeds, but after a while I was turning them out every 5-10 minutes.