Greetings, I asked here a few months ago about neandering grooves and dadoes. Someone suggested I get a router; at the time I made a 3/8" grooving plane which used a chisel for the blade. My later groove sides were still wobbly. Frid showed a neat little saw in one photo in volume 1.
I found a "stair saw" for sale on eBay. Saved the photo, opened it in Illustrator, messed around a bit with the lines, and prototyped the resultant plan in a chunk of scrap pine. Mindful of the discussion here about transferring drawings to wood, I traced the cut-out paper pattern with a pencil. Cut the outline with my turning saw, and picked out the details with a coping saw. Rasped, pared, and sanded to shape.
I bought one lot of cruddy noname saws on eBay. ( One is a pre-1918 Disston panel saw, 11 pt x 18". ) From the worst of the Warren & Ted blades I hacksawed my new stairsaw blade. Recut the teeth at 12° with a 15° fleam so I could rip and crosscut. The original saw was 7 pt; the eBay item was 6 pt. I kept the 7 pt spacing. I set the teeth very slightly.
Drilled holes and filed them to slots for adjustment of cut depth. Used a couple of the sawnuts from the sacrificed saw. Dang, the thing works!
I have a scrap of 5/4 ash that I intended to use for the production version. Dunno, I may just slap some shellac on the pine prototype and use it.