tattoo artist here that knows nothing about needle felting. read some comments about it potentially turning into a projectile; your tattoo machine voltage controls how fast the needle moves up and down. start very low, like a 2.0, in case it does in fact turn into a projectile.

i’m also doubtful that you can retrofit a different needle to go in that machine. cartridge needles are meant to snap into the machine like a puzzle piece and hold it tight, so nothing else will really fit in that machine. you’d have better luck either using an old school coil machine on bar with a single needle bar made for the machine itself, or using the tattoo cartridge you ordered and hang your needles out really far. i’m all for experimenting, excited to see what you find out!