Lock Miter technique

[John Keane]

I have been using a lock miter bit for a couple of days. I have gotten a good fit, but I am not comfortable with the vertical cut process. Any tips or suggestions that make the process more comfortable would be appreciated. Main discomfort is moving the board through the bit. I keep my fingers out of the way, but the board movement seems forced.
Running at 19000 RPM on PC 1718 with a zero (+ - ) aux fence. Birch wood.

[Jim Becker]

I think that for something like that (I don't own or use this type of cutter), I'd build a sled that moved along the fence, holding the workpiece safely vertical through the cut.

[Brad Kimbrell]

And if your bit is as large as mine --- SLOW THAT ROUTER DOWN!

I wouldn't run my 2 1/2" bit faster than 10K if possible. Maybe you have a smaller version, but that sounds awfully fast.

I use a sled much like a coping sled but holds the work vertical like a tenoning jig on a tablesaw.

Good luck and stay safe!

An embarrasing story on my bit - my first cut was at 15K with a DW615 in the table... And I decided to try it on a "soft" pine 2x4 first - the only problem was that I attempted to take a full cut!!! After I pulled the splinters out of my forehead and had my fingers put in a splint, I moved that fence just a tad and took several lighter cuts.

Now I use it only for baltic birch ply and have not have the problem since. I guess 1 1/4" cut on the end of a 2x4 was a little too much! :eek: :mad:

[John Keane]

I measured the bit and it was 2". I then went to the Pat Warner speed guide and he recommended 18K for a bit of 1" + to 2". My PC choice was 16 or 19 so I took 19. I like your and Jim becker's idea for a sled. There has to be a simple way to keep downward pressure on the piece as well as tight to the fence. It sure makes a nice glue joint when it is done right.