i just chopped up a first batch of pins for a little sauna project (my first timber frame) and i'm wondering about proper dimensions at the tapered end. these are 1 inch pins, 1 foot long, rough octangonal (axed), out of black ash (using mostly the sapwood- is this proper? or should i go into the heartwood?) at the end of the taper they are 3/8 inch. when i compare what i have to the pictures of pins in john rempel's 'building with wood' they look pretty much the same but a bit skinnier at the end. compared to a pin from a timber framer friend (HI NEVILLE if you're on here!!11) the taper is definitely more slender.

my concern is whether there's a potential for a skinny tip to break as the drawbore is driven home, jamming up the joint. any thoughts on this? thanks.