# CLEARANCE HOLES FOR METRIC FASTENERS

"Clearance holes for metric fasteners" calculator was developed to calculate the recommended clearance hole sizes from M1.6 through M64 for bolts, screws and studs in three classes of clearance using close-, normal- and loose-fit category. The recommended metric drill bit size for each class of clearance hole is shown in calculation results. The calculator also shows nearest substitute inch drill bit size for metric fasteners.

This calculator was developed by using the charts which are given in the ASME B18.2.8-1999 - " Clearance holes for bolts, screws and studs" standard.

### Metric Clearance Hole Calculator:

 INPUT PARAMETERS Nominal Screw Size M1.6 M2 M2.5 M3 M4 M5 M6 M8 M10 M12 M14 M16 M20 M24 M30 M36 M42 M48 M56 M64 Fit Class Normal Close Loose

 RESULTS Parameter Value Nominal Screw Size --- mm Fit Class --- -- Nominal Metric Drill Size --- mm Nearest Inch Drill Size --- in Minimum Hole Diameter --- mm Maximum Hole Diameter ---

### Definitions:

Clearance hole: A hole on a part where threaded section of a bolt can pass.

Drill bit: A cutting tool used in drilling machines to drill a hole.

### Supplements:

 Link Usage Metric clearance hole chart Tabulated form of the metric clearance hole calculator.

### Reference:

• Oberg, E. , Jones ,F.D. , Horton H.L. , Ryffel H.H., (2016) . Machinery's Handbook . 30th edition.  Industrial Press Inc.
• Oberg, E. , Jones ,F.D. , Horton H.L. , Ryffel H.H., (2012) . Machinery's Handbook . 29th edition.  Industrial Press Inc. , pp 1609 - 1612
• ASME B18.2.8-1999, Clearance holes for bolts, screws and studs