At last, I have the Onefinity working. My project now is a clock dial, etched in 1/32” brass. Parts of the lettering are very fine (only 0.008” wide at the surface). The parts that are wider (0.015”) need to be deep enough to accept the black wax that makes letters more visible. Having broken the tips off two blades, I’m asking whether to change settings, tools or goals.
The blades are single-flute inserts in the Amana (12 mm) shaft. They both are 30 degree V bits (solid carbide). The first bit had a tip diameter of 0.005”, and the second was 0.01”. Between efforts I got e-mail advice from Amana and after the second fail I spoke with them. Here are the set-ups:
Try #1
- Tip 0.005” (Amana RCK-360)
- 6000 RPM, 20 Inch/min (IPM per their table)
- Pass depth 0.008
- Full depth 0.015
- Left protective plastic on the brass
Try #2
- Tip 0.01” (Amana RCK-361)
- 6000 RPM, 47 Inch/min (IPM per their table)
- Pass depth reduced to 0.005
- Full depth increased to 0.02
- Took off plastic. (Flip side of the same sheet as the first try)
They suggested reducing both the pass depth and IPM by 50% (0.002” passes, and 20 IPM)
Though they were kind and are sending replacement blades, I’m not confident. Does anyone have advice on settings, or am I using the wrong tool for this job?