Bridge Notching Trouble

[Ron Nossaman]

>I'll have some bridge notching coming up in a while. I have always had 
>some trouble in the past keeping the notched top edge sharp. By this I 
>mean I line the chisel up in the middle of the bridge pin holes, start my 
>downward stroke (I try to do a bit of a curve so that the top edge is a 
>large angle - not vertical, but more vertical than horizontal), but then 
>after going downward the first tiny bit (maybe one millimeter or so), I 
>need to angle the chisel more toward the horizontal. At that point I find 
>my chisel riding on the top bridge-pin-line edge that I just cut so nice 
>and cleanly. The riding motion tends to round off the nice top edge that 
>you want to be ever-so sharp. How not to do that? I can see that cutting a 
>straight angle would fix that problem, but I've always thought that the 
>steeper you can make the top edge, the better the termination (assuming 
>you don't undermine the bridge pin). I think Fazioli puts a vertical drop 
>on their bridges. Those pianos sound OK to !
>me.
>
>Terry Farrell

As usual, there's a tradeoff. The sharper the angle, the weaker the 
termination edge. A little shallower angle at the edge will still provide 
good termination and give you more room to work, as will a flatter scoop. I 
find a slight rounding (less than a millimeter, and probably under 5°) of 
the flat side of my chisel helps me, but I'll still rub the edge if I scoop 
too deep. I take a couple of chisel strokes to rough out the bulk, a couple 
to establish the bevel angle and depth to the side cut I've already made 
and get it close to bisecting the pin holes, and a light pass to finish. 
Some report good luck with a big curve on the "flat" side of the chisel 
that's a little tighter than the curve of the scoop profile you like in 
your notch. I've seen brochures with guys notching from the side. Everyone 
seems to do it different.

Ron N