Hex Bit Brush Handle with Screw Lock

I designed this because I wanted a screwdriver handle grip for a set of nylon bore brushes I use for removing internal strings from 3d prints. Sometimes it's difficult to find the right bottle brush but the nylon bore brushes come in every size you need. I tried a couple other handle grip designs but they were designed to hold a bit in with a built-in printed spring and rotating end caps. That may work for a screwdriver bit, but I need an handle that is rigid and where the bit does not come out when you pull on it. This handle will solve that problem, the brush or other bit will lock in tight. I also added a hole through the handle to help remove a bit if you get one stuck inside. 

The ideal screw size is M3 x 6mm long socket capscrew, but a longer screw will still work. The M3 machine screw should be self-tapping without drilling first. Be careful about over tightening the screws or you may need to print a replacement handle.

This model is easy to print in PLA or PETG without supports. I designed it to be printed on either end but I would recommend you place the back of the handle on the build surface because the surface area is a little larger.