Unified High Tensile Hexagon Bolts

ANSI/ASME B18.21.1 1972 (R1983)

Materials and Finishes

Steel 8.8/Zinc & clear 

Stainless steel/Self colour 

Brass/Self colour

Please note: Not all sizes stated are available from stock, please enquire for availability.

Note: Due to the fact that fastening applications differ greatly, the below information is for guidance only and is correct to the best of our knowledge. The customer must satisfy themselves with the performance of the fastener and validity of the data. TR Fastenings will not be held responsible for any failure that may occur from the use of this information

Technical Support Articles
Pre-load and Tightening Torques for Steel Fasteners - Standard Metric Threads
Torque Data - Austenitic Stainless Steel
Dimension data
d (thread size)1/4 UNF5/16 UNF3/8 UNF7/16 UNF1/2 UNF9/16 UNF5/8 UNF3/4 UNF7/8 UNF1 UNF1.1/8 UNF1.1/4 UNF1.3/8 UNF1.1/2 UNF1.3/4 UNF
1/4 UNC5/16 UNC3/8 UNC7/16 UNC1/2 UNC9/16 UNC5/8 UNC3/4 UNC7/8 UNC1 UNC1.1/8 UNC1.1/4 UNC1.3/8 UNC1.1/2 UNC1.3/4 UNC
D max0.4380.5000.5620.6250.7500.8120.9381.1251.3121.5001.6881.8752.0622.2502.625
H nom0.1630.2110.2430.2910.3230.3710.4030.4830.5630.6270.7180.8130.8780.9741.134
L1< 6in0.7500.8751.0001.1251.2501.3751.5001.7502.0002.2502.5002.7503.0003.2503.750
L1> 6in1.0001.1251.2501.3751.5001.6251.7502.0002.2502.5002.7503.0003.2503.5004.000


Technical Support Articles
UNC thread sizes
UNF thread sizes
Tightening factors & tolerances