Precision-machined threads ensure smooth assembly and a secure fit in bothUNC (coarse) andUNF (fine) sizes. 1/4"-20 UNC (Coarse) 7/16" (0.438") 7/32" (0.218"). 5/16"-18 UNC (Coarse) 1/2" (0.500") 17/64" (0.266").
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