Brass Knurled Thumbscrew suit Marking Gauges by Joseph Marples Useful for replacing lost screws or to revamp old saws for use. These have an M5 thread and have a 12mm diameter head. They are intended to fit handles around 25mm thick. Sold as individual screw and cap complete. 3 different screws and caps: solid brass or brass plated or solid brass split nut style.