Match the hole to the screw body
The pilot hole supports the threaded portion of the screw. Use the fastener and wood species as the starting point, then test in scrap when the work is visible or structurally important.
Use clearance holes for clamped joints
A clearance hole in the top piece lets the screw pull the second piece tightly against it. This can improve joint closure when using screws with glue or mechanical joinery.
Control the head and depth
Countersink or counterbore deliberately so the head seats correctly without crushing fragile veneers or weakening a thin workpiece.
Shop 101
Turn this guide into a tested shop decision.
You leave with one documented input, one controlled result, and one clearer next action.
- Name the material, dimension, or cost input that affects the decision.
- Use the guide and calculator to make the assumption visible.
- Test or compare the result before committing final material, time, or client scope.
Related tools & lessons
Common questions
Why did my board split when I drove a screw?
Common causes are no pilot hole, a pilot hole that is too small, a screw too close to an edge or end, brittle stock, or an oversized fastener.
What is a clearance hole?
It is a hole large enough for the screw shank to pass freely through the top material, allowing the threads to draw the mating piece tight.
Should I test pilot holes first?
Yes. Test on offcuts of the same species and thickness, especially for hardwood, thin stock, face frames, or visible work.