Wood Screws Manufacturer in India | DIN 7996, DIN 7997 & ASME B18.6.1

Overview

DIN 7996, DIN 7997 & ASME B18.6.1 Wood Screws: Manufacturer & Supplier

A wood screw makes its own thread in timber. The coarse, sharp thread and gimlet point bite into the wood, and the plain shank under the head lets the board you are fixing slide, so the head pulls the joint tight.

Exotic Alloy manufactures wood screws in Mumbai, India, for furniture, joinery, cabinet, boat and door makers. We supply across India and to Nepal, the Gulf, Africa and Europe, in metric DIN sizes from 1.6 to 10 mm and in ASME inch gauges.

One screw family, two systems

Metric wood screws share one thread, DIN 7998, under six head standards. Inch wood screws are sized by gauge number to ASME B18.6.1. For hex-head timber screws see coach screws and lag bolts; for the head geometry in more depth see round head and oval head screws.

DIN 7996 / 7997 DIN 96 / 97 / 95 ASME B18.6.1 Pozidriv & Phillips A2 / A4, brass

Wood screw at a glance

Thread: Coarse, sharp, core ≈ 0.7 d (DIN 7998)
Point: Gimlet point
Shank: Plain under the head
Heads: Round, countersunk, raised countersunk
Drive: Slot, Phillips (H), Pozidriv (Z)
Related: Coach, countersunk, hanger bolts

A 5 × 40 DIN 7996 round head wood screw, like the ones in our photo, drawn to scale. Head, recess and thread from DIN 7996 and DIN 7998.

Specification

Wood Screw Specification

The range we manufacture and supply.

Metric standardsDIN 95, 96, 97 (slotted); DIN 7995, 7996, 7997 (cross recess); thread DIN 7998

Inch standardASME B18.6.1, gauges No. 0 to No. 24

Metric sizes1.6–10 mm (DIN 97), 2–8 mm (cross recess)

HeadsRound, countersunk, raised countersunk (oval)

DriveSlot; Phillips (H); Pozidriv (Z)

LengthRound: under the head; countersunk: overall

MaterialsSteel; brass; silicon bronze; stainless A2 / A4

FinishZinc plated clear or yellow; stainless and brass plain

CertificationMill certificate; EN 10204 3.1 on request

PackingBoxes of 100 to 5,000; bulk cartons

Head types

Round, Countersunk & Raised Countersunk Wood Screws

Three head shapes, each with a slot or a cross recess.

The six DIN wood screw heads for a 5 mm screw at the same scale. Slotted and cross recessed versions share the head size.

Head	Slotted	Cross recess	Sits	Use
Round	DIN 96	DIN 7996	On the surface	Fittings, hinges on surface, where countersinking is unwanted
Countersunk	DIN 97	DIN 7997	Flush	Flush joints, hinges, cabinets
Raised countersunk (oval)	DIN 95	DIN 7995	Flush rim, domed top	Visible joinery, trims, cup washers
Inch flat / oval / round	ASME B18.6.1 (slotted, Phillips)		As above	US-standard furniture and boats
Hexagon	DIN 571 (coach screws)		On a washer	Heavy timber, driven with a spanner

Screws that drill or form their own thread in metal have their own pages: self-drilling screws and thread forming screws.

Thread & point

Wood Screw Threads: DIN 7998 and ASME B18.6.1

Cut thread and rolled thread inch wood screws, and the DIN 7998 metric thread enlarged.

The wood screw thread is coarse and sharp-crested with a slim core: in DIN 7998 the core d₃ is about 0.7 d and the pitch is held to ±10 %. The thread runs out to a gimlet point that starts the screw without a drill in soft timber.

ASME B18.6.1 allows two makes. Cut thread: the shank equals the thread diameter and the thread is about two thirds of the length. Rolled thread: a thinner body, rolled up to full diameter, with a thread at least four diameters or two thirds of the length, whichever is greater.

Length tolerance (ASME)	Tolerance
Up to 5/8 in.	+0 / −0.03 in.
Over 5/8 to 1-1/2 in.	+0 / −0.05 in.
Over 1-1/2 to 2-3/4 in.	+0 / −0.06 in.
Over 2-3/4 in.	+0 / −0.09 in.

Threads per inch ±10 %. Metric: thread length about 0.6 l on DIN wood screws (product data).

Size d	d min h15	Core d₃ nom / min	Pitch P nom (±10 %)	Core / d	Pilot hole softwood 70 %	Pilot hole hardwood 90 %
1.6	1.2	1.1 / 0.7	0.7	0.69	0.8	1.0
2	1.6	1.4 / 1	0.9	0.70	1.0	1.3
2.5	2.1	1.7 / 1.3	1.1	0.68	1.2	1.5
3	2.6	2.1 / 1.7	1.35	0.70	1.5	1.9
3.5	3.02	2.4 / 2	1.6	0.69	1.7	2.2
4	3.52	2.8 / 2.4	1.8	0.70	2.0	2.5
4.5	4.02	3.1 / 2.62	2	0.69	2.2	2.8
5	4.52	3.5 / 3.02	2.2	0.70	2.4	3.1
(5.5)	5.02	3.8 / 3.32	2.4	0.69	2.7	3.4
6	5.52	4.2 / 3.72	2.6	0.70	2.9	3.8
(7)	6.42	4.9 / 4.42	3.2	0.70	3.4	4.4
8	7.42	5.6 / 5.12	3.6	0.70	3.9	5.0
10	9.42	7 / 6.42	4.5	0.70	4.9	6.3
12	11.3	9 / 8.42	5	0.75	6.3	8.1
16	15.3	12 / 11.3	6	0.75	8.4	10.8
20	19.16	15 / 14.3	7	0.75	10.5	13.5

DIN 7998, mm. Sizes in brackets should be avoided. Pilot holes: our calculation, 70 % / 90 % of the core d₃ nominal (USDA Wood Handbook rule).

Gauge	Basic D in / mm	Threads per inch	D max / min in	Rolled body E₁ max / min, in	Thread depth min, in	Root ≈ D − 2 × depth, in
No. 0	.060 / 1.52	32	.064 / .053	.055 / .044	.010	.040
No. 1	.073 / 1.85	28	.077 / .066	.066 / .055	.010	.053
No. 2	.086 / 2.18	26	.090 / .079	.075 / .064	.010	.066
No. 3	.099 / 2.51	24	.103 / .092	.086 / .075	.014	.071
No. 4	.112 / 2.84	22	.116 / .105	.095 / .084	.016	.080
No. 5	.125 / 3.17	20	.129 / .118	.107 / .096	.018	.089
No. 6	.138 / 3.51	18	.142 / .131	.118 / .107	.020	.098
No. 7	.151 / 3.84	16	.155 / .144	.127 / .116	.022	.107
No. 8	.164 / 4.17	15	.168 / .157	.136 / .125	.023	.118
No. 9	.177 / 4.50	14	.181 / .170	.147 / .136	.026	.125
No. 10	.190 / 4.83	13	.194 / .183	.157 / .146	.030	.130
No. 12	.216 / 5.49	11	.220 / .209	.176 / .165	.031	.154
No. 14	.242 / 6.15	10	.246 / .235	.201 / .190	.035	.172
No. 16	.268 / 6.81	9	.272 / .261	.214 / .203	.038	.192
No. 18	.294 / 7.47	8	.298 / .287	.237 / .226	.042	.210
No. 20	.320 / 8.13	8	.324 / .313	.260 / .249	.046	.228
No. 24	.372 / 9.45	7	.376 / .365	.303 / .292	.050	.272

ASME B18.6.1 Table 1, inch. D is also the body diameter of cut-thread screws. Root diameter: our estimate from the minimum thread depth.

Dimensions

Wood Screw Head Dimensions & Gauge Chart

Size d	Head d_k DIN 7997 / DIN 97	Head k max	Shank d_s min DIN 7997	Cross recess PZ / PH no.	Recess m H / Z	Slot n DIN 97	Slot depth t DIN 97 min / max
1.6	– / 3	0.96	–	–	–	0.4	0.32 / 0.45
2	3.8	1.2	1.6	0	–	0.5	0.4 / 0.6
2.5	4.7	1.5	2.1	1	2.7 / 2.8	0.6	0.5 / 0.7
3	5.6	1.65	2.6	1	2.9 / 3	0.8	0.6 / 0.85
3.5	6.5	1.93	3.02	2	3.9 / 4	0.8	0.7 / 1
4	7.5	2.2	3.52	2	4.4 / 4.2	1	0.8 / 1.1
4.5	8.3	2.35	4.02	2	4.6 / 4.4	1	0.9 / 1.2
5	9.2	2.5	4.52	2	4.8 / 5	1.2	1 / 1.3
(5.5)	10.2	2.75	5.02	3	6.2 / 6.1	1.2	1.1 / 1.4
6	11	3	5.52	3	6.6 / 6.3	1.6	1.2 / 1.6
(7)	12.5	3.5	6.42	3	6.8 / 7	2	1.4 / 1.9
8	14 / 14.5	4	7.42	4	8.7 / 8.5	2	1.6 / 2.1
10	– / 18	5	–	–	–	2.5	2 / 2.6

DIN 7997 and DIN 97 (2016), mm. Bold: at size 8 the head is 14 mm in DIN 7997 and 14.5 mm in DIN 97. Length l is measured overall, head included.

Size d	Head d_k = 2d	Head k DIN 7996 / DIN 96	Shank d_s min DIN 7996	Cross recess PZ / PH no.	Recess m H / Z	Slot n DIN 96	Slot depth t DIN 96 min / max
1.6	3.2	– / 1.1	–	–	–	0.4	0.55 / 0.7
2	4	1.4	1.6	0	–	0.5	0.7 / 0.9
2.5	5	1.7	2.1	1	2.3 / 2.4	0.6	0.85 / 1.1
3	6	2.1	2.6	1	2.7 / 2.9	0.8	1.05 / 1.35
3.5	7	2.35 / 2.4	3.02	2	3.7 / 3.9	0.8	1.2 / 1.6
4	8	2.8	3.52	2	4.1 / 4.1	1	1.4 / 1.8
4.5	9	3.1	4.02	2	4.4 / 4.3	1	1.55 / 2
5	10	3.5	4.52	2	4.8 / 4.7	1.2	1.75 / 2.3
(5.5)	11	3.8	5.02	3	6.2 / 6.2	1.2	1.9 / 2.5
6	12	4.2	5.52	3	6.6 / 6.7	1.6	2.1 / 2.7
(7)	14	4.9	6.42	3	7.3 / 7	2	2.45 / 3.2
8	16	5.6	7.42	4	8.8 / 8.5	2	2.8 / 3.6

DIN 7996 and DIN 96, mm. Length l is measured under the head. More on round heads: round head screws.

Gauge	Flat 82° A max / min × H	Oval A max × total O max	Round A max / min × H max	Round slot J max × T max	Phillips driver
No. 2	.172 / .147 × .051	.172 × .080	.162 / .146 × .069	.031 × .048	1
No. 3	.199 / .171 × .059	.199 × .092	–	–	1
No. 4	.225 / .195 × .067	.225 × .104	.211 / .193 × .086	.039 × .058	1
No. 5	.252 / .220 × .075	.252 × .116	.236 / .217 × .095	.043 × .063	2
No. 6	.279 / .244 × .083	.279 × .128	.260 / .240 × .103	.048 × .068	2
No. 7	.305 / .268 × .091	.305 × .140	.285 / .264 × .111	.048 × .072	2
No. 8	.332 / .292 × .100	.332 × .152	.309 / .287 × .120	.054 × .077	2
No. 9	.358 / .316 × .108	.358 × .164	.334 / .311 × .128	.054 × .082	2
No. 10	.385 / .340 × .116	.385 × .176	.359 / .334 × .137	.060 × .087	2
No. 12	.438 / .389 × .132	.438 × .200	.408 / .382 × .153	.067 × .096	3
No. 14	–	–	.457 / .429 × .170	.075 × .106	3

ASME B18.6.1, inch: flat Table 2, oval Table 6 and round heads. Flat and oval heads are listed to No. 12; the larger head values in our sources do not pass our geometry check, so we quote them on request.

Gauge	Basic D in	D mm	Pitch mm (tpi)	Nearest DIN size	DIN pitch mm
No. 2	.086	2.18	0.98 (26)	2	0.9
No. 3	.099	2.51	1.06 (24)	2.5	1.1
No. 4	.112	2.84	1.15 (22)	3	1.35
No. 5	.125	3.17	1.27 (20)	3	1.35
No. 6	.138	3.51	1.41 (18)	3.5	1.6
No. 7	.151	3.84	1.59 (16)	4	1.8
No. 8	.164	4.17	1.69 (15)	4	1.8
No. 9	.177	4.50	1.81 (14)	4.5	2
No. 10	.190	4.83	1.95 (13)	5	2.2
No. 12	.216	5.49	2.31 (11)	5.5	2.4
No. 14	.242	6.15	2.54 (10)	6	2.6
No. 16	.268	6.81	2.82 (9)	7	3.2
No. 18	.294	7.47	3.17 (8)	7	3.2
No. 20	.320	8.13	3.17 (8)	8	3.6
No. 24	.372	9.45	3.63 (7)	10	4.5

Basic diameter D = 0.060 + 0.013 × gauge (in). Nearest DIN size: our comparison; gauge and metric screws are not interchangeable.

Pilot holes

Clearance Hole, Pilot Hole & Countersink

Drill the top board to the screw size and the base to a pilot hole. Otherwise the thread grips both boards and holds them apart.

Clearance hole in the part being fixed: the screw size d, so the thread passes freely.
Pilot hole in the base: about 70 % of the core in softwood, 90 % in hardwood (USDA Wood Handbook), as deep as the screw goes.
Countersink for flat heads to the head diameter d_k: 90° tools for DIN, 82° for ASME heads.
Avoid end grain for loads: withdrawal there averages about 75 % of side grain and varies widely.

Gauge	Shank D clearance, in	Root ≈ in	Pilot, softwood 70 %: in (nearest 1/64)	Pilot, hardwood 90 %: in (nearest 1/64)
No. 2	.086	.066	.046 (3/64)	.059 (1/16)
No. 3	.099	.071	.050 (3/64)	.064 (1/16)
No. 4	.112	.080	.056 (1/16)	.072 (5/64)
No. 5	.125	.089	.062 (1/16)	.080 (5/64)
No. 6	.138	.098	.069 (1/16)	.088 (3/32)
No. 7	.151	.107	.075 (5/64)	.096 (3/32)
No. 8	.164	.118	.083 (5/64)	.106 (7/64)
No. 9	.177	.125	.087 (3/32)	.113 (7/64)
No. 10	.190	.130	.091 (3/32)	.117 (7/64)
No. 12	.216	.154	.108 (7/64)	.139 (9/64)
No. 14	.242	.172	.120 (1/8)	.155 (5/32)
No. 16	.268	.192	.134 (9/64)	.173 (11/64)
No. 18	.294	.210	.147 (9/64)	.189 (3/16)
No. 20	.320	.228	.160 (5/32)	.205 (13/64)
No. 24	.372	.272	.190 (3/16)	.245 (1/4)

Inch pilot holes: our calculation from the ASME root estimate. Metric pilot holes are in the DIN 7998 table above.

Load finder

Wood Screw Pilot Hole & Withdrawal Finder

Pick the screw and the timber to get the holes to drill and the ultimate pull-out load.

Screw & timber

System

Size

Timber

Screw length, mm

Into the base, mm

Driven into

Our calculation with the USDA Wood Handbook (FPL-GTR-190, ch. 8): ultimate withdrawal p = 108.25 G² D L (N, mm), D = screw size, L = thread in the base (thread taken as 0.6 l metric, 2/3 l inch); pilot hole 70 % (softwood) or 90 % (hardwood) of the core. G at 12 % moisture from Table 5-3; imported woods use basic G, which is slightly conservative. An average short-term ultimate test value, not a design load. In dense timber a long thread can break the screw before it pulls out.

Result

2.0

mm pilot hole

2.19

kN ultimate pull-out

Clearance hole (top board):4 mm

Core / root diameter:2.8 mm

Thread in the base:22 mm

Same load:224 kgf · 493 lbf

Designation:4 × 40 mm

Specific gravity of the timbers in the finder

Wood	G	Group	Basis	Ultimate withdrawal N per mm of thread, d = 4 mm
Western redcedar	0.32	Softwood	12 % MC	44
Eastern white pine	0.35	Softwood	12 % MC	53
Ponderosa pine	0.40	Softwood	12 % MC	69
Sitka spruce	0.40	Softwood	12 % MC	69
Redwood, old-growth	0.40	Softwood	12 % MC	69
Western hemlock	0.45	Softwood	12 % MC	88
Douglas-fir, Coast	0.48	Softwood	12 % MC	100
Loblolly pine	0.51	Softwood	12 % MC	113
Longleaf pine	0.59	Softwood	12 % MC	151
Yellow-poplar	0.42	Hardwood	12 % MC	76
Black cherry	0.50	Hardwood	12 % MC	108
Red maple	0.54	Hardwood	12 % MC	126
Black walnut	0.55	Hardwood	12 % MC	131
White ash	0.60	Hardwood	12 % MC	156
Yellow birch	0.62	Hardwood	12 % MC	166
Northern red oak	0.63	Hardwood	12 % MC	172
Sugar maple	0.63	Hardwood	12 % MC	172
American beech	0.64	Hardwood	12 % MC	177
White oak	0.68	Hardwood	12 % MC	200
Shagbark hickory	0.72	Hardwood	12 % MC	224
African mahogany	0.42	Hardwood	green (basic)	76
Iroko	0.54	Hardwood	green (basic)	126
Teak	0.55	Hardwood	green (basic)	131
Sapele	0.55	Hardwood	green (basic)	131
Jarrah	0.67	Hardwood	green (basic)	194
Keruing	0.69	Hardwood	green (basic)	206
Ipe	0.92	Hardwood	green (basic)	366

USDA Wood Handbook Tables 5-3a/b (12 % moisture content) and 5-5a (imported woods, basic specific gravity). Last column: 108.25 G² × 4 mm, our calculation.

Materials

Wood Screw Materials & Finishes

Material	Finish	Where	Note
Low-carbon steel	Zinc plated, clear or yellow	Dry interiors, furniture	Lowest cost
Stainless A2 (304)	Plain	Outdoors, damp timber, kitchens	As in our photo
Stainless A4 (316)	Plain	Coast, pools, chlorides	Molybdenum adds chloride resistance
Brass	Natural, polished	Visible joinery, hinges, restoration	Softer: drill the full pilot hole
Silicon bronze	Natural	Boats and marine woodwork	Copper alloy for wet timber

Steel

Cold heading

Zinc plated.

1018 1022

Stainless

A2 / A4

Outdoor and marine.

304 316

Brass

Decorative

Visible screws.

Brass grades

Silicon bronze

Marine

Boat building.

C65100

Manufacturing

How Our Wood Screws Are Made

1

Wire

Steel, stainless, brass or bronze wire, certified by heat.

2

Heading

Head and recess formed in one blow sequence.

3

Slotting

Slot headed or cut for DIN 95, 96 and 97.

4

Thread rolling

Coarse thread and gimlet point formed.

5

Finishing

Zinc plating or cleaning and passivation.

6

Packing

Counted boxes, lot-labelled.

Applications

Where Our Wood Screws Are Used

Furniture

Frames, rails and fittings.

Doors & windows

Hinges, locks and frames.

Cabinets & kitchens

Hardware on solid timber.

Boats

Bronze and A4 in planking and trim.

Outdoor timber

Pergolas, fences and garden furniture.

Crafts & restoration

Slotted brass for period work.

Quality & testing

Wood Screw Inspection & Certification

Check	Method	Applied to
Head d_k, k	Callipers to DIN / ASME	Every lot
Recess fit	PZ / PH gauge	Every lot
Thread d, pitch	Optical comparator	Every lot
Point	Visual, drive test in timber	Every lot
Length	To the length tolerance	Every lot
Material	PMI / chemical analysis	Stainless, brass, bronze

Every shipment includes

Mill certificate with heat number
Dimensional report
Lot number on every box

On request

EN 10204 3.1 certificate
Salt spray test for plated lots
RoHS declaration

FAQ

Wood Screw Questions, Answered

A wood screw is a screw for timber with a coarse, sharp thread, a gimlet point and usually a plain shank under the head. The thread cuts its own mating thread in the wood, and the plain shank lets the top board slide so the head can pull it tight. Metric wood screws follow DIN 95, 96, 97 and DIN 7995, 7996, 7997 with the DIN 7998 thread; inch wood screws follow ASME B18.6.1.

The USDA Wood Handbook bases its withdrawal values on lead holes of about 70 % of the thread root diameter in softwoods and about 90 % in hardwoods. For a 4 mm screw with a 2.8 mm core that is about 2.0 mm in softwood and 2.5 mm in hardwood. The top board needs a clearance hole the size of the screw so the thread does not grip it.

It sets the diameter in ASME B18.6.1: the basic diameter is 0.060 inch plus 0.013 inch for every gauge number. A No. 8 screw is 0.164 inch (4.17 mm) with 15 threads per inch and a No. 10 is 0.190 inch (4.83 mm) with 13. Metric wood screws are sized directly in millimetres.

The drive. Both are round head wood screws with a head twice the screw size across, 10 mm for a 5 mm screw. DIN 96 has a slot; DIN 7996 has a cross recess, form H for Phillips or form Z for Pozidriv. The screws in our photo are DIN 7996 form Z.

In withdrawal from side grain the USDA Wood Handbook gives an ultimate test load of 108.25 times G squared times D times L newtons, with G the specific gravity of the wood, D the shank diameter and L the thread penetration in millimetres. A 4 mm screw with 22 mm of thread in Douglas-fir (G 0.48) gives about 2.2 kN. This is an average short-term ultimate value, not a design load; in end grain expect about 75 % of it.

ASME B18.6.1 allows both. A cut-thread screw has a shank as thick as the thread and a thread about two thirds of the length. A rolled-thread screw has a thinner body, 0.125 to 0.136 inch against 0.164 inch for No. 8, and a thread of at least four diameters or two thirds of the length, whichever is greater.

About 60 % of the length on DIN wood screws, for example 27 mm on a 5 x 45 DIN 7996 screw; the rest is a plain shank. Choose the length so that the thread sits in the base timber and the plain shank passes through the part being fixed.

Zinc-plated steel for dry indoor work, A2 stainless outdoors and in damp timber, A4 stainless near the sea or around chlorides, and brass or silicon bronze for boats and visible joinery. Brass is softer than steel, so drill the full pilot hole and drive brass screws with care.