BRANZ Guideline February 2012 screw gauges

Issue 36 – March 2012

Engineers who are specifying screw gauges for structural applications need to be aware of shank diameter differences that occur for a given gauge. For example, for a 10 gauge screw shank, the diameter can range from 2.74 mm to 5.12 mm. The former would only equate to a 4 gauge screw using Table 4.5 in NZS 3603:1993 Timber structures Standard, which requires a 10 gauge screw to have a minimum shank size of 4.88 mm.

BRANZ suggest that, when specifying, it would be safer to state the minimum shank diameter rather than specifying the gauge.

Related Standard

 

Published in building.