if you have access to a lathe and an old DC degreed timing wheel(which is the same outer diameter as the dampener), you can use a bolt and nut to temporarily attach it to the dampener. Chuck up dampener & wheel in lathe. Line up the degree wheel "zero" with the TDC mark, then use a sharp tool(like a threading tool, rotated 90 degrees) in a tool holder, and lined up exactly with each desired increment on the wheel, and run the saddle back and forth and scribe the dampener however many lines you need, then use some 1/8" stamps to stamp every 10 degrees. It's surprisingly easy to do.