Guide / Thread Standards

Thread Types: Metric, UNF, BSP, NPT

Quick reference for screw thread standards worldwide

Thread Comparison

StandardAngleSeal MethodCommon Use
Metric (M)60 degCompressionGeneral mechanical
UNC/UNF60 degCompressionUS/NA mechanical
BSP (G)55 degCompression (P)EU hydraulic
NPT60 degTaper interferenceUS pipe

M10x1.5 = 10mm dia, 1.5mm pitch (coarse). M10x1.25 = fine pitch. Bolt grade markings: 8.8 (640 MPa yield), 10.9 (900 MPa), 12.9 (1080 MPa).