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Screw & Drill Bit Chart
Look up pilot and clearance hole sizes by screw gauge for softwood and hardwood so fasteners seat cleanly without splitting the workpiece.
Softwood Pilot
Hardwood Pilot
Clearance Hole
Full Reference Table (Tapered Wood Screws)
| Gauge | Softwood Pilot | Hardwood Pilot | Clearance Hole |
|---|---|---|---|
| #4 | 1/16" | 5/64" | 7/64" |
| #6 | 5/64" | 3/32" | 9/64" |
| #8 | 3/32" | 1/8" | 11/64" |
| #10 | 7/64" | 9/64" | 3/16" |
| #12 | 1/8" | 5/32" | 7/32" |
| #14 | 9/64" | 11/64" | 1/4" |
Pilots, Clearance Holes, and Screw Selection
A wood screw needs two different holes when you clamp one board to another: a clearance hole in the top piece (threads free) and a pilot in the bottom piece (threads bite). Skip the clearance hole and the screw head can sit proud while the joint never pulls closed. Undersize the pilot in oak or maple and the board splits; oversize it in pine and the screw spins without holding.
How to use this chart
- Select the screw gauge (#4 through #14) from the dropdown.
- Read softwood pilot, hardwood pilot, and clearance bit sizes for that gauge.
- Cross-check the full table below when you are stocking a drill-bit set for the shop.
Gauge vs length and material tips
Gauge sets shank and thread diameter; length is chosen for how deep the threads engage the receiving piece—typically at least half the thickness of the secondary board for butt joints, more for softwoods. Near ends and edges, always drill; even softwood can split on a dry winter day. For pocket screws and confirmat-style fasteners, follow the manufacturer’s bit, not this tapered wood-screw chart. Brass and soft stainless need a full-depth pilot—they torque off easily in hardwood.
FAQ
Do I need a clearance hole in every joint?
Whenever one piece must pull tight against another. If both pieces are thick enough that the threads only enter the second piece, clearance in the first is what lets the joint clamp.
Softwood or hardwood pilot for plywood?
Use the hardwood column for dense hardwood plywood and Baltic birch; softwood pilots work better in fir / pine cored softwood plywood and solid softwoods.
Are these sizes for modern construction screws?
They target traditional tapered wood screws. Coarse deck screws and structural screws often ship with matching bits—prefer those specs when provided.
Should I countersink before or after drilling the pilot?
Drill the clearance/pilot path first, then countersink (or counterbore for a plug) so the bit follows a centered hole and does not walk.
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