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Westfield Fasteners Product Specification:

DIN 440 Type V - Wood Construction Washers, with Square Hole

This product guide contains the specification for metric wood construction washers (type V), standard parts available from Westfield Fasteners. The basis of this specification is the DIN standard DIN 440.

Product Description

Washers for timber or wood construction (DIN 440 type V) include a square hole. This is an unusual feature, designed for use with bolts that include a square section on the neck of the shank below the head, such as with coach or carriage bolts. The large size of the timber washer and this square hole will help prevent the bolt from spinning as it's tightened and will protect the surrounding area of the fixing point.

These wood construction washers are generally used with softwoods and will support and add to strength to the joint. The increased bearing surface of the washer will help to accommodate the movement in the wood as the timber expands and contracts with changes in humidity.

Scope of the DIN Standard.

DIN 440 specifies the requirements for these wood construction washers with a larger outside diameter. This standard covers two types: washers with a round hole (type R) and the type V square holed washers we are concerned with here. This standard includes data for type V washers for nominal diameters from M5 to M22. The standard specifically states that these washers are designed primarily for use in nut and bolt assemblies for timber construction.

The standard states a hardness class of 100 HV for these washers.

Figure 1: Timber Construction Washer to DIN 440 (Type V)

Table 1: Dimensions & Tolerances according to DIN 440 (mm)

Nominal Size	For Thread Size	Hole Diameter, a		Outside Diameter, d2		Thickness, h
		min. (nominal)	max.	max. (nominal)	min.	nominal	max.	min.
5.5	M5	5.5	5.8	18	16.9	2	2.3	1.7
6.6	M6	6.6	6.96	22	20.7	2	2.3	1.7
9	M8	7	9.36	28	26.7	3	3.6	2.4
11	M10	11	11.43	34	32.4	3	3.6	2.4
14	M12	14	14.43	44	42.4	4	4.6	3.4
18	M16	18	18.7	56	54.1	5	6	4
22	M20	22	22.84	72	70.1	6	7	5
24	M22	24	26.84	80	78.1	6	7	5

For further details, please refer to the ISO/DIN standard document for this item.