This is one of the “simple” tools that I have made and kicked myself afterwards. It took less than 30 minutes to make, and saves me about 5-10 minutes per hinge!

For background I’ve been making a fair number of hinges lately, and I realized that it would be useful if I could put together a tool to “set” the curve of a hinge, rather than working to hammer the metal repeatedly onto the pin to make it conform nicely. When thinking about this I realized that the solution would be similar to a rivet set, but instead of a dome, as used in a rivet set, I needed a “gutter”. The easiest gutter I could think of was to drill through a chunk of steel and then cut through it. Instead of spending lots of time analyzing (my normal modus operandi) I decided to try it, and then adjust if it didn’t work. My first pass Worked remarkably well, taking a significant bite out of my hinge build times, and making it easy tobuild a nice clean hinge knuckle. Before I get into the details (and pictures) I figured I’d provide a nice table outlining the size of drill you will need to get appropriate clearance for a 1/8″ pin:

The table is a fancy way of taking the difference between your hinge pin size and the drill bit size and divide by 2. You will note that I included some “silly” sizes, since for armour there is no point making a “hinge set” on metal significantly thinner than 1/32″ / 22 ga (3/16″ for a 1/8″ hinge pin). In general I make my hinges with material ranging from 0.5 to 1mm (24 Ga to 20 Ga) so I decided to make this tool with a 7/32″ hole.