What Size Drill Bit

Pilot hole for a #6 wood screw

Hardwood

7/64"

Softwood

3/32"

Use a standard twist drill of this size for the threaded part of a #6 screw. Oak, maple and other dense woods take the larger bit.

7/64" 0.138" thread

Using a taper-point (countersink) bit set? Those sizes are 9/64" for hardwood and 1/8" for softwood.

#6 wood screw pilot hole sizes

Screw diameter0.138 in 3.51 mm
Hardwood, standard bit7/64" 0.1094 in
Softwood, standard bit3/32" 0.0938 in
Hardwood, taper-point bit9/64" 0.1406 in
Softwood, taper-point bit1/8" 0.1250 in

Which size to pick

A pilot hole lets the screw thread bite without splitting the wood. If the screw turns hard or the wood starts to split, go up one bit size. If it spins without holding, go down one.

Test on a scrap piece first. Wood density varies, so the same species can call for a different size.

These sizes are for the threaded section only. The upper board needs a clearance hole the size of the screw's smooth shank.

Tools for this job

As an Amazon Associate we earn from qualifying purchases. Details

Nearby sizes