Steel Hex Head Screws for Wood

These steel screws have corrosion-resistant finishes. Also known as lag bolts, they have a hex head for a secure grip with a wrench. They press threads into material for a tight, secure hold. To prevent splitting, drill a pilot hole slightly smaller than the screw. Length is measured from under the head.

Black-oxide steel screws have a coating that protects the steel from rusting in dry environments and blends in with dark surfaces.

Zinc-plated steel screws resist corrosion in wet environments.

Hot-dipped galvanized steel screws have a thick coating for better corrosion resistance than zinc-plated steel screws. They're a good choice for ACQ-treated (arsenic-free) lumber.

Hexagon Head Wood Screws
DIN 571
d(mm)	ds(mm)		k(mm)			s(mm)
	min	max	Nom	min	max	min	max
4	3.52	4	2.8	2.5	3.1	6.64	7
5	4.52	5	3.5	3.13	3.88	7.64	8
6	5.52	6	4	3.63	4.38	9.64	10
7	6.42	7	5	4.63	5.38	11.57	12
8	7.42	8	5.5	5.13	5.88	12.57	13
10	9.42	10	7	6.55	7.45	16.57	17
12	11.3	12	8	7.55	8.45	18.48	19
16	15.3	16	10	9.55	10.45	23.16	24
20	19.3	20	13	12.1	13.9	29.16	30