Adjustable Drill Blade

A similar design has already been implemented using a narrow strip of metal, and this craft is based on a stud or a long bolt. This device is made for cutting holes of different diameters in sheet material.

To implement the idea, you need to grind the hairpin from one of the sides and drill three holes. In the central hole there will be a drill, which must be fixed with two nuts on both sides.

In the other two holes of the stud there are bolts with sharpened ends, they are also fixed with nuts. Craft is quite simple to manufacture and may well solve the problem of cutting round holes for a specific production task.