mini sled and half laps technique.

[LCHIEN]

I find myself using half laps for various things - a really strong joint with lots of glue area,
A half lap is a wide dado or a wide non-thru cut.

I find myself struggling to line up the mark on the face of the workpiece with the blade since it involves leaning over the workpiece to see its front. A mark on the top is hard because the blade meets the workpiece at the base and gives too much parallax.

I finally came up with this solution. The BT3 SMT is about half a sled. I used a glued up L-bracket as sacrificial so as not to cut the BT3 miter fence, but give support to short pieces on both sides of the cut. Its a mini-sled, very simple. It keeps the piece from twisting under the force of pushing it through the blade.


(Yes, that is the famous Rod Kirby Miter fence. He sent it to me when he retired his BT3.)
So the fence is about a little taller than the miter fence and usually held with a clamp.

I made a one in wide cut through it an inch high. This is good enough for using a regular blade or a 3/4" wide dado and narrow enough to support most short pieces. The height is good enough for half laps in 1x and 2x lumber.

I slide the mini-sled so the right or left side of the blade kisses the opening in the mini-sled.



So now its easy to view the backside exit point of the blade edge. I can mark the back of the piece (saddle square help a lot) and see exactly where the exit will be and line up the workpiece so the mark lines up with the edge in the mini-sled.

To cut the other edge, I just slide the min-sled to the left until it kisses the blade.

It went from an awkward reaching, trial and error process to a slide and set accurately on first try, process.

Yes, that's a safety block on the right clamped to the rip fence as a stop for length after positioning the mini-sled. It is short so that the rip fence is not tight to the workpiece to cause kickback. I have a dedicated block exactly one inch wide that uses a rockler fence clamp to mount it, I keep the front rail rip scale so that zero corresponds to the fence against the blade so it reads rip width perfectly. When using the miter fence for cross cutoffs, and the safety block, the rip fence reads the length of the cutoff + one inch. I.e. want a four inch cutoff, set the scale to 5 inches.

[LCHIEN]

if I'm whacking out a lot of these I'll put a dado in to cut 3/4" at a time.

But when I have just a few, I'll use the regular blade and make a series of cuts about an 1/8" apart. Approximate is OK.
I use a depth about 1/16th less than the final desired depth.

Use a screwdriver or a 1" chisel to bend and break these at the root.



Remove the leaves



and then I use a 3/4" dado cleanout bit with a top bearing in a router table- very fast and easy to guide with the vertical sides guiding the bit and squaring off the inside corners.


top is the finished cleanout and the bottom after breaking and removing the leaves,
much smoother than even multiple dado passes.