Boring

counter bore I dislike the look of saw screws that sit on the surface of the wood, so they need to be inset. Which isn’t all that easy if you try to do it with Forstner and regular bits (drill a small (1/16”) pilot, counter sink both sides, then drill out to screw diameters). One of the blogs on back saws mentioned using a piloted counter bore, these are usually for metal so I was all over it. It consists of two parts: the counter bore (sorta like a end mill in that it bores a flat bottomed hole) and the pilot, which has two diameters: one that fits in the pilot hole to center the counter bore and the shank that fits inside the counter bore itself. The counter bore I use is 7/16” and a 3/16” pilot with 5/32” shank.
Using the saw plate as a template, I drill (use a drill press with a depth stop!) a 3/16” hole at each plate hole (3/16” because it is close to the body drill for a #10 screw (which is a #11 drill, 0.1875” vs 0.1910”) and you can get a 3/16” pilot), then counter bore each side. I use 7/16” because that is the size of Lee Valley counter sink washers. I make the T nuts out of brass rod with a 1/4” shank so I have to drill out one side from 3/16” to 1/4”. I usually screw this up (need another counter bore!) but not too badly so it works OK (if not, I just drill out to 17/64”).

counter bore2         OLYMPUS DIGITAL CAMERA

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