Centre Finder

Beta This jig is in beta: the files are generated and checked, but the design may still change. Check the drawing against your instrument before you cut.

One printed body, two rollers on ball bearings and a marking hole in the middle. Laid across a workpiece and turned until both rollers touch the edges, the marker sits on the exact centre — on a tapered neck as well as a parallel one, because the rollers roll instead of dragging.

Photograph to come

Centre finder

The body, both roller modules and the centre insert you choose, as printable files. Pick the span, the two rollers and the marker, and the bundle carries exactly those parts.

Open

What goes to whom

To the laser shop: the template DXF and the base plate DXF, both on 5 mm cast PMMA. Cut the CUT layer only — ENGRAVE is surface marking and PLYWOOD is not for the laser at all.
To your slicer: the 3MF, which carries every printed part already standing in its print orientation. The STLs are there if you would rather plate them yourself.
To your own bench: the assembly STEP, which opens as a tree of named parts in FreeCAD, and the bundle's README.