ISO 8750 - Spiral Roll Pins

This product guide contains the specification for metric sized spiral roll pins, a series of standard parts available from Westfield Fasteners. The basis of this specification is the internationally recognised ISO standard ISO 8750.

Product Description

Spiral roll pins are similar to slotted spring pins, but are constructed from a spiral of steel, forming a tube shape.
These are stronger than the single coil of the slotted spring pin, exerting pressure more evenly around it's circumference, which helps to absorb vibrations better.
Spiral roll pins are also known as coiled spring pins.

Scope of the ISO Standard.

ISO 8750 specifies the characteristics of the standard duty coiled spring type straight pins with nominal diameters from 0.8mm to 20mm inclusively.

The diameter of the hole into which the slotted pin is inserted should be equal to the nominal diameter d1 of the mating pin and to tolerance class H12. When the pin is in the smallest permitted hole, the slot should not be fully closed.

Table 1 below defines the overall dimensions and tolerances of coiled spring pins. Minimum shear strength values given in this table are applicable to steel and martensitic stainless steel (a) and for austenitic stainless steel (b) which includes 301 grade stainless steel, a material choice available from Westfield Fasteners for these items.

d₁	nom		0.8	1	1.2	1.5	2	2.5	3	3.5	4	5	6	8	10	12	14	16	20
	Before Mounting	max	0.91	1.15	1.35	1.75	2.25	2.78	3.30	3.84	4.40	5.50	6.50	8.63	10.80	12.85	14.95	17.00	21.10
	Before Mounting	min	0.85	1.05	1.25	1.62	2.13	2.65	3.15	3.67	4.20	5.25	6.25	8.30	10.35	12.40	14.45	16.45	20.40
d₂	Before Mounting	max	0.75	0.95	1.15	1.40	1.90	2.40	2.90	3.40	3.90	4.85	5.85	7.80	9.75	11.70	13.60	15.60	19.60
a	=		0.3	0.3	0.4	0.5	0.7	0.7	0.9	1	1.1	1.3	1.5	2	2.5	3	3.5	4	4.5
s			0.07	0.08	0.10	0.13	0.17	0.21	0.25	0.29	0.33	0.42	0.50	0.67	0.84	1	1.20	1.30	1.70
Minimum Shear Strength, Double, kN		a	0.4	0.6	0.9	1.45	2.5	3.9	5.5	7.5	9.6	15	22	39	62	89	120	155	250
Minimum Shear Strength, Double, kN		b	0.3	0.45	0.65	1.05	1.9	2.9	4.2	5.7	7.6	11.5	16.8	30	48	67	-	-	-

ISO 8750 - Spiral Roll Pins

Figure 1: Spiral Roll Pin

Table 1: Dimensions & Tolerances according to ISO 8750