1/4" Screwdriver Bit Handle With Retaining Bead

myminifactory

I like to reinvent the wheel, even if there are many other interchangeable screwdriver handles available. I've never seen one that incorporates a retaining ball like the type used in ratchets and socket drivers, so I decided to give it a try. This is only my second model in FreeCAD, and I still have no idea what I'm doing, but I think this turned out pretty good, if I do say so myself. I initially printed this without any ridges because I forgot that I wanted to include them, so there's a v2 of the handle with ridges. You can use this either with or without the ball, and it's worth trying both ways. The ball is held in place by a small pin that passes through a hole on the side of the handle. To secure the pin, I wrap several wraps of electrical tape around the handle over the pin, which serves as an external spring that keeps the BB pressed in while allowing it to retract when pulling the bit out. For the ball, you'll need a standard 4mm BB and a small, 4mm diameter spring. Insert the BB into the hole on the side of the handle first, then cut the spring so that you have three or four loops, depending on how much resistance your spring has. Insert the spring behind the BB with the uncut end facing the ball. Next, apply glue to the edges of the pin and push it into the hole, lining up the pin with the contour of the handle body. Clamp the pin in place overnight, making sure that it's securely attached. If the pin pops out when you insert the bit into the handle, try printing it slightly larger or cutting off one loop at a time from your spring to reduce the pressure on the pin.