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Bought into the hype on self-centering drill bits... still on the fence | Carpenters - SMM Buzz

Bought into the hype on self-centering drill bits... still on the fence

Picked up a set of self-centering bits for cabinet hinges. Thought they'd save me time. First three holes were dead perfect. Then one slipped on a knot in the maple. Threw my whole door alignment off by 2mm. Has anyone else had these things fail on tricky grain?

3 comments

3 Comments

the_adam5mo ago

Are you drilling into face grain or edge grain on those hinge holes? I've messed up more than a few mortises because the self-centering bit caught a knot and walked just like you described. @evan_burns95 is right on the money - you really have to watch the grain direction with these bits, especially on harder woods like maple. My approach is to mark the center with an awl first, then use a sharp brad point bit to start the pilot hole by hand for the first couple turns. After that, you can switch to the self-centering bit with way less risk of it wandering off. I keep a center punch in my apron pocket for this exact reason, it saves me from having to fill and redrill. Your mileage may vary, but I've had better luck taking that extra 10 seconds to pre-mark things on tricky grain.

evan_burns955mo ago

...and that's exactly why I stopped using them on anything other than plywood or softwood. Had a similar thing happen with a set of self-centers on some red oak last year. Pilot hole went in fine with the bit, but when I tried to drive the screw, it walked off center because the bit had already made a shallow divot from a tiny knot I missed. Whole drawer face ended up crooked by a hair and I had to rebuild the thing. Now I just stick with a brad point bit and a good center punch for maple or anything with grain that looks like it might fight back. Saves me the headache of a 2mm mistake that turns into a whole afternoon of fixing.

jenniferw824mo ago

Am I the only one who's had a self-centering bit just completely give up on a knot and chew up the hole? I had one spin so bad on some cherry it left a burn mark I had to sand out.