If buying perfect 1/2” dowels is just too convenient and easy, you can slow production down the old school way by using a dowel rounding plane. It works much like a pencil sharpener, only bigger and significantly slower. This one from the Japan Woodworker Catalog recreates an 18th century Scottish design.
This simple tool, made of maple with a hardened tool steel cutter blade, will make a properly-sized dowel out of whatever strange wood you can’t find in round stock at the local wood supply place. You just cut away the corners of the stock, then twist that sucker against the dowel rounding plane. Note: be prepared to invest some serious time in this project.
Prices start at $8.
1/2″ Dowel Rounding Plane [The Japan Woodworker Catalog]