Requires 6x 8 1" bolts and lock nuts. Just another centering scribe for woodworking. It doesn't require a screw to hold the pencil, though, rather just a strong friction fit to keep it in place and truly centered. And should you want to have the bolts a little tighter it can be stiff enough to hold position and be used to transfer an edge position from one piece to another. It is also quite easy to operate one handed.

Print two arms and two braces and the one pencil holder.