Hi there, I'm new to this business, just got my kit yesterday.
Doing my first groove today I had my dremel go ballistic on me (jumping all around the place) causing a mess on the plate and messing up my groove.
It is a cheap unit and the brass insert in the chuck that holds the bit got chewed out by the pressure I guess.
The bit then sat crooked causing it to go all over the place.
Moral of the story, do yourself a favor and buy proper good quality tools.
I was pretty easy on it, I think the $40 dremel is fine for bone carving or the likes.
Ones it starts to jump around a bit the forces on the chuck are amplified, it just did not like it.
I have no problems with my proper dremel 4000