I have been struggling to cut a seat in 22K tubing with a setting
bur. This was not a problem a few years ago and has more recently
become impossible. I have called the techs at both Stuller & Rio
Grande and they usually suggest another brand of bur.
What happens is the bur polishes the metal rather than cutting it.
The burs are so fine and they seem to get gummed up in the 22K gold.
I found an older bur that I used to use and counted nine cutting
edges with one cutting edge that seems to stick up a little from the
other cutting edges which forms something similar to a brad point
twist drill bit; these old burs work beautifully and remove a long,
fine ribbon of gold.
The newer burs seem to have 16 or more cutting edges, which in fact
do not cut 22K gold at all.
Has anyone else run into this problem, suggestions of where I could
find setting burs with fewer cutting edges (like 9)?
Any input would be appreciated.