Maker & Reference
Wood Screw Pilot Hole Calculator
Too small = split wood. Too big = stripped threads. Match pilot to wood density and screw size.
Pilot bit
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- Decimal (in)
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- Countersink
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- Shank clearance
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FAQ
Two-stage pilot needed? +
For #8 screws into hardwood: yes — pilot for threads, shank clearance hole through the top board so it pulls tight. Single hole works for softwood.
Self-tapping screws? +
Construction/deck screws with type-17 (auger) tips do not need pilots in softwood, but pre-drill within 2" of edges to prevent splitting.