Andrew Zajac Embossing Tool - this tool is hand-made from tempered high-carbon steel. The very tip is carefully sharpened to the correct specification to allow it to emboss the slot effectively without shredding or otherwise damaging the slot. I test each tool to make sure the tip is correct.
Embossing increases the efficiency of the reed as it goes through the slot. By using a tool to
press down onto the edges of the slot, a small ridge of metal is created in the slot. This ridge
decreases the space between the reed and the slot. The closer tolerance will cause the reed to
make more sound and require less breath force to activate.
To benefit most from embossing, you need to emboss the entire slot. For a quick shortcut, see these instructions on only embossing half of the slot.
Full-length slot embossing can be easy! The embossing tool is effective on stainless steel as well as brass reed plates. I recommend using a generous amount of mineral oil when using this tool. If you over-emboss a slot, the presence of oil also speeds up the process of plinking and clearing away burs. The oil is easily washed away after the embossing is complete.
The tool is made small because embossing is more about precision than force. Apply pressure with your fingers instead of the weight of your arm and you will save time and have a lot of success.
The tool can be groomed with some fine sandpaper once in a while to keep it in working order for a very long time - at least several hundred harps. You won't have to worry about wearing it out.
Embossing takes practice and you need to know how to check the work you are doing. This video provides instructions on how to emboss and check your work.