Westfield Fasteners Product Specification:

DIN 933 - Hex Head Set Screw (Fully Threaded Hex Bolt)

This product guide contains the specification for metric threaded Hex Head Set Screws, a series of standard parts available from Westfield Fasteners. The basis of this specification is the internationally recognised DIN standard DIN 933.

Product Description

The DIN 933 / ISO 4017 hex bolt, is a fully threaded hexagon head bolt widely used in engineering, manufacturing, maintenance and construction applications. Commonly referred to as a set screw or machine bolt, this versatile metric fastener provides a reliable and secure method of assembly across a broad range of industries.

Unlike the partially threaded DIN 931 hex bolt, the DIN 933 bolt features a full thread along the entire shank, making it suitable for applications where maximum thread engagement is required. The hexagon head design allows high tightening torque to be applied using a standard spanner, socket or ratchet, helping to achieve a secure fastening.

DIN 933 / ISO 4017 fully threaded hex bolts have been used worldwide for decades and remain one of the most popular fastening solutions for machinery, equipment, structural assemblies and general engineering projects.

DIN 933 Hex Head Set Screw Technical Drawing

Figure 1: Hexagon Head Set Screw

Notes to figure 1:

Point (b) is chamfered or for threads equal to or greater than M4, it may be as-rolled (sheared end).
There may be up to 2 incomplete threads at the end of the bolt (c).
d - reference datum for dw.
ds pitch diameter (e).
Permissible alternative shape (f).

Unless otherwise stated, all products conform to DIN 933. The equivalent ISO 4017 standard differs only in the head dimensions specified for M10, M12 and M14 thread diameters.

Please note that, due to manufacturing limitations, nylon DIN 933 bolts are manufactured to dimensions similar to the standard but cannot be supplied in full compliance with all requirements of the DIN 933 specification.

Typical Applications

DIN 933 hex head set screws are commonly used in machinery, equipment manufacture, steelwork, maintenance operations, automotive assemblies and general engineering applications where a fully threaded fastener is required.

Scope of the DIN Standard

DIN standard DIN 933 specifies the characteristics, tolerances and variation in form of metric sized hex head set screws, and covers thread diameters from M1.6 up to and including M52. Mechanical properties for these items are defined in ISO 898 and ISO 3506. Table 1 below defines the overall dimensions and tolerances for hexagon head set screws, whilst table 2 defines the same for what are considered non-preferred threads. Table 3 defines the tolerance on the shank length.

DIN 933 has specific provision for mild steel, 8.8 and 10.9 hi-tensile steel, stainless steel and non ferrous metals, which may include brass.

Although the DIN 933 standard has now been withdrawn and superceded by ISO 4017, off the shelf parts are generally still manufactured to the older specification.

Variations from DIN 933

ISO 4017, which replaces DIN 933, specifies revised dimensions and tolerances for hex head set screws, most particularly new head dimensions for M10, M12, M14 and M22. Parts manufactured specifically to ISO 4017 dimensions are available on request, subject to availability.

ISO 4014 is an equivalent standard, covering hex head bolts with a partially threaded shank.

Thread, d				M1.6	M2	M2.5	M3	M4	M5	M6	M8	M10	M12	M16	M20	M24	M30	M36	M42	M48
p				0.35	0.4	0.45	0.5	0.7	0.8	1	1.25	1.5	1.75	2	2.5	3	3.5	4	4.5	5
a			max	1.05	1.20	1.35	1.5	2.1	2.4	3	3.75	4.5	5.25	6	7.5	9	10.5	12	13.5	15
c			max	0.25	0.25	0.25	0.40	0.40	0.50	0.50	0.60	0.60	0.60	0.80	0.80	0.80	0.80	0.80	1.00	1.00
c			min	0.10	0.10	0.10	0.15	0.15	0.15	0.15	0.15	0.15	0.15	0.20	0.20	0.20	0.20	0.20	0.30	0.30
d_a			max	2.0	2.6	3.1	3.6	4.7	5.7	6.8	9.2	11.2	13.7	17.7	22.4	26.4	33.4	39.4	45.6	52.6
d_w	Product grade	A	min	2.4	3.2	4.1	4.6	5.9	6.9	8.9	11.6	15.6	17.4	22.5	28.2	33.6	-	-	-	-
d_w	Product grade	B	min	-	-	-	-	5.7	6.7	8.7	11.4	15.4	17.2	22.0	27.7	33.2	42.7	51.1	59.9	69.4
e	Product grade	A	min	3.41	4.32	5.45	6.01	7.66	8.79	11.05	14.38	18.9	21.1	26.75	33.53	39.98	-	-	-	-
e	Product grade	B	min	3.28	4.18	5.31	5.88	7.50	8.63	10.89	14.20	18.72	20.88	26.17	32.95	39.55	50.85	60.79	71.30	82.60
k	-	-	nom	1.1	1.4	1.7	2	2.8	3.5	4	5.3	6.4	7.5	10	12.5	15	18.7	22.5	26	30
	Product grade	A	max	1.22	1.52	1.82	2.12	2.92	3.65	4.15	5.45	6.56	7.68	10.18	12.72	15.22	-	-	-	-
	Product grade	A	min	0.98	1.28	1.58	1.88	2.68	3.35	3.85	5.15	6.22	7.32	9.82	12.28	14.78	-	-	-	-
	Product grade	B	max	1.30	1.60	1.90	2.20	3.00	3.74	4.24	5.54	6.69	7.79	10.29	12.85	15.35	19.12	22.92	26.42	30.42
	Product grade	B	min	0.90	1.20	1.50	1.80	2.60	3.26	3.76	5.06	6.11	7.21	9.71	12.15	14.65	18.28	22.08	25.58	29.58
k_w	-	-	min	0.7	0.9	1.1	1.3	1.9	2.28	2.63	3.54	4.28	5.05	6.8	8.5	10.3	12.8	15.5	17.9	20.9
r	-	-	min	0.1	0.1	0.1	0.1	0.2	0.2	0.25	0.4	0.4	0.6	0.6	0.8	0.8	1	1	1.2	1.6
s	-	-	nom=max	3.2	4	5	5.5	7	8	10	13	17	19	24	30	36	46	55	65	75
	Product grade	A	min	3.02	3.82	4.82	5.32	6.78	7.78	9.78	12.73	16.73	18.67	23.67	29.67	35.38	-	-	-	-
	Product grade	B	min	-	-	-	-	6.64	7.64	9.64	12.57	16.57	18.48	23.16	29.16	35.00	45.0	53.8	63.1	73.1

Thread, d				M3.5	M7	M14	M18	M22	M27	M33	M39	M45	M52
p				0.6	1	2	2.5	2.5	3	3.5	4	4.5	5
a			max	1.8	3	6	7.5	7.5	9	10.5	12	13.5	15
c			max	0.40	0.5	0.60	0.80	0.80	0.80	0.8	1.0	1.0	1.0
c			min	0.15	0.15	0.15	0.2	0.2	0.2	0.2	0.3	0.3	0.3
d_a			max	4.1	7.8	15.7	20.2	24.4	30.4	36.4	42.4	48.6	56.6
d_w	Product grade	A	min	5.1	9.6	20.5	25.3	30.0	-	-	-	-	-
d_w	Product grade	B	min	-	9.4	20.1	24.8	29.5	38.0	46.5	55.9	64.7	74.2
e	Product grade	A	min	6.58	12.12	24.49	30.14	35.72	-	-	-	-	-
e	Product grade	B	min	-	11.94	23.91	29.56	35.03	45.20	55.37	66.44	76.95	88.25
k	-	-	nom	2.4	4.8	8.8	11.5	14	17	21	25	28	33
	Product grade	A	max	2.52	4.95	8.98	11.72	14.22	-	-	-	-	-
	Product grade	A	min	2.28	4.65	8.62	11.28	13.78	-	-	-	-	-
	Product grade	B	max	-	5.04	9.09	11.85	14.35	17.35	21.42	25.42	28.42	33.50
	Product grade	B	min	-	4.56	8.51	11.15	13.65	16.65	20.58	24.58	27.58	32.50
k_w	-	-	min	1.6	3.19	5.96	7.8	9.6	11.7	14.4	17.2	19.3	22.8
r	-	-	min	0.1	0.25	0.6	0.6	0.8	1	1	1	1.2	1.6
s	-	-	nom=max	6	11	21	27	32	41	50	60	70	80
	Product grade	A	min	5.82	10.73	21.67	26.67	31.61	-	-	-	-	-
	Product grade	B	min	-	10.57	21.16	26.15	31	40.00	49.0	58.8	68.1	78.1

mm	+/-
	Product grade
	A	B
2-3	0.2	-
4-6	0.24	-
8-10	0.29	-
12-16	0.35	-
20-30	0.42	1.05
35-50	0.5	1.25
55-80	0.6	1.5
90-120	0.7	1.75
130-150	0.8	2
160-180	-	2
200	-	2.3

DIN 933 - Hex Head Set Screw (Fully Threaded Hex Bolt)

Figure 1: Hexagon Head Set Screw

Notes to figure 1:

Table 1: Dimensions & Tolerances according to DIN 933 (Preferred Threads)

Table 2: Dimensions & Tolerances according to DIN 933 (Non-Preferred Threads)

Table 3: Shank Length Tolerance according to DIN 933