What's a good trick to cut a precise v-notch in a piece of sizing
and ring shank so they match perfectly?
With practice the human eye is very very good at calculating angles.
Practice on scap till you can see the difference. At Bowman we had to
develop the ability to file both rod and sheet to a perfect 90 degree
fit on multiple pieces. they would be grouped at random, and if
pressure at the end of the row of pieces caused them to buckle at
all, you tired again. You eventually master the file, the feel and
the eye, if you are determined enough to keep trying.
"Triangle Files - You will have to play with these from a size and a
cut size, but they will work perfectly after you practice abit. E-Me
if I can help in any way to help use these tools!.
Don't cut a vee notch. Much easier to cut a round notch in your
sizing piece and round the ends of the ring shank. Use a narrow
round edge joint file for the round groove. Slight angle differences
don't destroy the fit with the two round surfaces.