CenterMarker

Here's a quick way to make a center finder for all sorts of applications in your workshop.

I used to measure it with a ruler - unbelievable (primitive and inaccurate).

The device is not a new invention, but from the 3D printer (or with a few wooden strips) it is a quick and valuable aid.

3D printer

or alternatively

several wooden strips & glue

The tool consists of a right angle with a ruler at a 45-degree angle. The ruler is de-centered so that the pencil line is exactly in the middle.

Well, just download the file, print it on your 3d printer and in a short time the tool will be on the plate. Scale it in any size you want.

If you don't have a 3D printer, you can also make the tool from wood or weld it from metal. This is not described here, but: Right angle, divided by a ruler at a 45-degree angle

Place the right angle well against the edge of the round piece and draw a line with a pencil. You need at least two lines. Make three to check the accuracy.