M3 M4 M5 Rivnut Setting Nut Wrench
This is a 150 x 24 x 12 mm handle for setting rivnuts (threaded inserts for thin sheet metal) with a hardware-store bolt, a hex nut and a washer instead of a $30 setting tool. It has three captive nut sockets: M3 (5.7 mm), M5 (8.2 mm) and M4 (7.2 mm) across flats. Each socket has a clearance bore through the 6 mm floor. To use it, thread the bolt fully into the rivnut and hold the bolt still with a hex key. Then turn the bar so the captive nut drives down onto the washer and collapses the rivnut.
garage rivnut rivet-nut hex-nut