i test some of the machines i have with this STROBOSCOPIO, all machines run at 10 VOLTS, with tube needles and rubberband

-NO IRON, ACTION- 6700 rpm

-DRAGONFLY- 5100 rpm

-SWASHDRIVE GEN. 7, SOFT CLIP - 6400

-DRAGONFLY COPY FROM CHINA - 6.200

i try also one of my coils i use for shading, is basicly liner machine with long spring on front, i realy like for shading, very fast, but not strong, easy for me and run at 7900 rpm

and i try a NEXT GENERATION HALF COIL ALUMINIUM, one of my favorit machine of all time, adn run at 5900 rpm

on ROTARY depend also how many RUBBER BAND u use, how strong are, that machines are lube or not, many different things can change the speed, of course, im sure some DIRECT DRIVE can run faster, but i don realy see the positive things on run so fast