Allen Nut System of Measurement Inch Insert Diameter 5/16 in Overall Length 5/16 in Installed Length Not Applicable Thread Size M5-0.80 Thread Direction Right Hand Thread Type Coarse Flange Diameter Not Applicable Flange Thickness Not Applicable Material Steel Material Grade/Class Grade 2H Finish Black Oxide Body Texture Knurled Compatible Material Metal Drill Bit Size 21/64 in Maximum Hole Diameter 0.327 in Minimum Material Thickness 0.319 in