BOLT GAUGES: THREAD-CHECKER NUTS/BOLTS/SCREWS

Solid steel thread checker on wire lanyard. Used to gauge standard fastener sizes from #6-32 through 1/2-20. Thread gauges are used to identify size

Fastener Screw Bolt Nut Thread Measure Gauge Size Checker Standard & Metric Wire

How To Identify Bolts (US Standard and Metric)

Determining Bolt & Nut thread sizes by RCF Bolt & Nut

BoltSize-It - Bolt and Nut Checker 3459

Thread Gauge - Standard Sizes

Fastenal Industrial Supplies, OEM Fasteners, Safety Products & More

Identibolt – Stupid Simple Tools

Screw, Bolt, & Nut Gauges From Albany County Fasteners

Thread Detective for Guitars - StewMac