I will have to try the wintergreen oil. Keeping the bottom of the graver clean helps, build up can be a problem. Different types of aluminum as with other metals cut differently.
Try some type of lube and a sharp graver. Aluminum depending on what type is gummy and seams to tear as the graver passes through it. I have used Tap Magic with good results, but it does have an odour to it, At this moment i am drawing a blank on the others
The one I like best is from Steve Lindsay. Very smooth and easy to move a vise on. I have an old GRS it works but not as smooth .
Others have used a Potters turntable and say they are good which makes sense, as it it built to hold wet clay.
Eric
I find on Aluminum, cutting the design first is the best. As stated by the best too many chances of a mistake. Bike parts have many raised areas and corners, a mistake can be disaster to fix.
Cut then clean out to add depth to your background area. The metal is thick enough to go deeper and...
Back when I did some of that I had the plating shop buff the stuff first. Supposedly none to be done after. Worked good, only one small issue I seen and the owner didn't. That item was one of a few left in the copper state while the others were chromed out.
Eric
Monk I would think if you drop a email to any top turbine tool maker they could steer you in the right direction. There are some on here that do use air grinders as well.
Good Luck.
Eric