Clearance hole answer
3/8 bolt Clearance Hole Size
For 3/8 bolt, a common close-fit clearance is 13/32 in and a looser free-fit clearance is 7/16 in.
3/8 bolt clearance hole quick answer
| Fastener | Nominal diameter | Close fit | Free fit | Use note |
|---|---|---|---|---|
| #8 screw | 0.164 in | 11/64 in | 3/16 in | Use close fit for alignment; free fit when parts need assembly clearance. |
| #10 screw | 0.190 in | 13/64 in | 7/32 in | A printed or painted part may need the larger free-fit hole. |
| 1/4 bolt | 0.250 in | 17/64 in | 9/32 in | Close fit is common for locating; free fit is easier for field assembly. |
| 5/16 bolt | 0.313 in | 21/64 in | 11/32 in | Check washer bearing area if oversizing the hole. |
| 3/8 bolt | 0.375 in | 13/32 in | 7/16 in | Choose fit based on alignment and coating thickness. |
| 1/2 bolt | 0.500 in | 17/32 in | 9/16 in | Verify against your fastener standard for critical work. |
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.
Related references
Clearance Hole ChartCompare close-fit and free-fit clearance holes for common screws and bolts.Pilot Hole vs Clearance HoleThe difference between pilot holes, tap drill holes, and clearance holes with practical examples.Drill Size ChartFind fractional, number, letter, and metric drill sizes with decimal inch and millimeter equivalents.