Allen Nut System of Measurement Inch Insert Diameter 13/32 in Overall Length 27/64 in Installed Length Not Applicable Thread Size 1/4 In.-20 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 27/64 in Maximum Hole Diameter 0.421 in Minimum Material Thickness 0.419 in