Clearance hole answer

5/16 bolt Clearance Hole Size

For 5/16 bolt, a common close-fit clearance is 21/64 in and a looser free-fit clearance is 11/32 in.

5/16 bolt clearance hole quick answer

FastenerNominal diameterClose fitFree fitUse note
5/16 bolt0.313 in21/64 in11/32 inCheck washer bearing area if oversizing the hole.

Close fit or free fit?

Close fit helps location and alignment. Free fit is easier when parts are painted, plated, cut by hand, or assembled in the field. Use the drawing if it specifies a fit class.

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