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Westfield Fasteners Product Specification:

Hexagonal Combi Nut with Captive Washer

This product guide contains the specification for metric threaded hexagonal combi nuts with a captive washer. Stock items available from Westfield Fasteners.

Product Description

Combi nuts are a combination fixing featuring an integrated free spinning conical washer. As the nut is tightened, the edges of the conical washer dig in and grip the adjoining surface. This action helps to prevent the nut from loosening with vibration and changes in temperature. Combi nuts are also known as conical K-lock nuts, conical Kep nuts or comby nuts.

Commonly used with automotive parts and in machine construction, combi lock nuts speed up assembly time and are useful in awkward and overhead situations.

Scope of the Standard

These parts are not produced to a standard, but spanner sizes appear to follow those specified in DIN 934 for full hexagon nuts. Figure 1 and table 1 state the main dimensions for each size available.

Figure 1: Hexagonal Combi Nut with a Captive Conical Washer

Table 1: Dimensions & Tolerances (mm)

Thread, d	dc	f	h	m	Spanner Size
M3	8	1.25	0.6	2.4	5.5
M4	10	1	0.65	3.2	7
M5	15	1.6	1.25	4	8
M6	18	2.2	1.5	5	10
M8	18	2.2	1.5	6.5	13
M10	22	2.5	1.6	8	17