We had tens of thousands of these custom low profile serrated flange nuts manufactured for our construction customer using Grade 5 steel material with Dacromet zinc flake finish. 1″-8 thread was tapped with 2B thread fit prior to plating and the low profile height was set to .437″ max. Flange diameter was set to 1.46-1.50″, which is to standard 1″ diameter flange nut specifications. Full certs were provided with the parts, including 3rd party testing results for proof load, tensile strength, core hardness, and raw material composition.