This is a linear/arc wood scriber to draw linear lines or curves parallel to edge.

Hardware
4 pieces 608zz bearings
2 pcs M8 hex 40mm screws
2 pcs M8 hex nuts
1 pc M6 250mm threaded rod
2 pcs M6 hex nuts
2 pcs M4 screws 20mm
2 pcs M4 square nuts
2 pcs M4 wing butterfly nuts
1 pencil ~7mm diameter

Maybe you have to heat one of the M6 hex nuts to fit in pencil holder piece.

Of course you may found in ebay similar tools for ~25 USD.. :-)

Prusa

Prusa Clone

Yes

Yes

300

25