Thread: Best 6-mm bit for roughing out 15-mm deep blind holes for bow tie wedges?

Assuming this is ‘show’ work, I’d want a spiral down cut to avoid any chance of splintering - even though you are roughing out, tear out can track irritatingly far along the grain... it won’t enjoy an initial plunge cut, so if you’re in the middle of a piece of stock, use a larger drill bit (eg forstner) first to give the bit chip clearance from the get go. That would be my approach if using a router.
(TBH, if using chisels to finish, it might be quicker to cut the whole thing with them)

Originally Posted by Nekton

I need to rough-out some 15-mm deep blind holes for bow ties (George Nagashima/butterfly ties) before cutting back with chisel to final edges.
What would be the best bit (6-mm axle) to fit a Makita plunge router to do this job?
Here is a web page with the "chigiri" I'l be using (walnut 55-mm wide, 15-mm deep):
DIY工作材料＞チギリ

Hi Nekton
I see you are in Tokyo.
Know that 6 mm shank (axle) bits are not the same as 1/4" shank (axle) bits.
6 mm shanks will only fit into a 6 mm collet.
1/4" shanks bits require a 1/4" collet.

Check and check again before purchasing a bit that doesn't fit your router's collet.


as to the "best" bit -- a relatively inexpensive straight bit will work PROVIDED you first drill a larger diameter clearance hole using a forstner or brad point bit to start the router cutter in.
But first use your marking knife to cut around the "chigiri" outline.

Mark out the size of the blind holes with a chisle then use an upcut spiral bit

Thanks for all the advice—I'm going to practice a lot before attempting this!