Lock Miter Bit & Setup Block

[Joe Scharle]

It's been many years since I've had one of these. And I threw that one away! But looking at John Nixon using one to make edge jointed legs, I thought I'd try it again. The bit & block from MLCS arrived yesterday and I fiqured I make a box for it as a test piece. Nixon has a good video as does MLCS. And when they 'mentioned' tearout; well they coulda' at least raised their voices a little! It's a big bit with a radical geometry and will rip the living @&% off the back edge if it's not supported TIGHTLY. I made this little box today and left the tearout where it is to remind me 6 months from now. Don't even buy this bit without the approiate setup block. MLCS makes one for each size bit. With the block, the very first cut was right on the money for both pieces. Here's some pix showing tearout and non-tearout. All tearout happens as the piece comes off the bit and after I realized hand clamping wasn't gonna get, the rest was made clamped to the push/backing pad.

[toolferone]

I like the bit box. A question though. When using the set up block doesn't the stock you are using have to be the same thickness as the set up block?

[Joe Scharle]

Actuallt Tom, this block has a 3/4" edge and a 1/2" edge for setup using exact wood thickness. However, you can shim the 1/2" edge upwards by one-half the increase in thickness. IOW, shim the block up by 1/16" for 5/8" material and depth the fence another 1/16".
Nothing can go wrong; go wrong; go wrong!

In actual practice, I use 1/2" for drawer sides and 3/4" for ends, so it's idiot-proof for me.

[toolferone]

Joe, I undersand the major adjustments. The shim thing works just a bit of a pain when you surface your stock to .715 instead of .750. I guess you get it close and tweak it a little.

[Alan in Little Washington]

Joe, a couple of questions-

• Did you rough miter the corners first to remove excess stock?
• Did you use a zero clearance router table fence insert?
• Did you use a backer board to reduce tearout?