Dear Sarah, Marring of the surface can be a symptom of several
factors. With practice, it is possible to set without marring to the
extent of removing more metal than necessary.
Those factors includes how the hammer-piece is held, the impact
setting, type and/or condition of the tip and how securely the
jewelry piece is held.
Holding the hammer-piece at an angle would cause the tip's edge to
leave dent marks. Hold the tip as flat with the surface as possible.
Use the lightest impact setting as possible. When moving a good deal
of metal, 'sculpt' the metal as if you are forming with a combination
of burnishing and chasing, leaving less marring.
The hammer-piece tip should be flat and kept smooth. I use the
standard tip that comes with the Badeco swiss hammer handpiece. I
use the Crocker Graver Sharpener and block stones to keep the tip
surface smooth and polished. Some setters like to lightly roll off
the edges of the tip to minimize 'edge dents' .
Secure the jewelry piece to take advantage of the 'impact'. A wooden
clamp held against the pin vise would soften the impact. Take
advantage of the impact energy by using a more solid approach. Use
heaver metal clamps such as the BenchMate. For setting channels on
rings, a ring mandrel can be used.
Daniel Biery Jr.