Wood Screws

Wood screws have coarse, deep threads and usually an unthreaded shank. The shank exists so the top piece can be pulled tight — if the thread ran to the head, both pieces would be held apart by their own threads and never close.

Specification options

Available options. Actual capability is confirmed on enquiry.
Volume range	M1.0 – M5.0
Maximum size	M16
Standards	DIN 96 · DIN 97 · DIN 571 · ISO 1482 · ISO 1483 · JIS B 1112
Materials	see Materials
Finishes	see Finishes
Minimum order	From 10,000 pcs, depending on the part

Head styles

Countersunk

Oval

Bugle

Drive types

Phillips

Torx

Slotted

Square

Hexext

When to choose each →

Choosing the thread

Fully threaded

Maximum grip; for single-layer or end fixing.
Partially threadedwith shank

For drawing two pieces together. The shank passes through the upper piece without engaging, so the head can pull it down.

Where it most often goes wrong

Each of these causes scrapped lots or rework on the floor. None of them is theoretical.

No pilot hole in hardwood. Driving straight in splits the timber, especially near ends and edges. Pilot in two diameters: shank diameter for the plain section, root diameter for the threaded one.

The pilot rule is multiplied by the wrong diameter. The Wood Handbook states the pilot hole as a percentage of the root diameter — and a few pages later, in the same chapter, its screw-number table lists the shank diameter:

Wood Handbook shank diameter by screw number
No.	mm	in
4	2,84 mm	0.112 in
6	3,51 mm	0.138 in
8	4,17 mm	0.164 in
10	4,83 mm	0.190 in
11	5,16 mm	0.203 in
12	5,49 mm	0.216 in
14	6,15 mm	0.242 in
16	6,81 mm	0.268 in

The handbook never lists a root diameter for wood screws, so the reader applies the percentage to the number in front of them. Root is smaller than shank, so the error always goes one way: a hole that is too big. Nothing breaks, the screw drives beautifully, and the withdrawal load the formula was meant to predict no longer applies because its own stated condition was not met. We will not give a millimetre pilot figure for a No. 8 here for the same reason — there is no root diameter we can cite. ⚠ And the datum changes within the chapter: the lag-screw rule is written against shank. The rule names the wood species, which is the part nobody quotes.

Countersunk head without a countersink. The cone pulls itself flush; in hardwood without a prepared countersink it splits the surrounding fibre instead.

Zinc plating outdoors. It does not last, and ACQ-treated timber contains copper, which accelerates corrosion of a zinc coating. Outdoor timber needs hot-dip galvanised, stainless or a proprietary coating.

How length is measured

One rule covers it: if the head sinks into the work, measure overall; if it stays on the surface, measure under the head.

Three head styles compared: countersunk measured overall, oval to the cone intersection, pan under the head — The red line is the datum. Heads that sink into the work are measured overall; heads that stay on the surface are measured under the head.

Measurement datum by head style
Head style	Datum	Why
Countersunk (flat)	Overall length	The head sits flush in the countersink, so it counts
Oval (raised countersunk)	Overall to the head diameter	The cone sinks, the dome stays proud; measure to where they meet
Pan / round	Under head	The head stays entirely on the surface
Button	Under head	Same
Hex / hex washer	Under head	Same
Socket head cap	Under head	Same

Full explanation →　 Where the standards stop at this size →　 Tolerance stack-up and the screw →

Enquiries

Wood Screws come in a lot of combinations. Tell us the item, size, material, finish, annual usage and application, and we will come back on feasibility and lead time. A drawing or a sample is fastest — quoting against the real part saves a great deal of guessing.

Volume range M1.0 – M5.0, standard fasteners up to M16. Minimum order From 10,000 pcs, depending on the part.

sales@tigerfasteners.com

Request a quotation

Tell us the part and the quantity. We will come back on feasibility, lead time and price.

Or email us directly　sales@tigerfasteners.com