Why is my device not holding a bit?
I am trying to put a new bit in my rotary tool but it keeps falling off when I try to adjust it
Rotary tools use different sized bits. Commonly a Tool like a Dremel uses a 1/4" collet size. A dental tool, such as the one I use, a Emesco jack rabbit uses 7/16" bits.
Make sure your bits are the correct size.