Westfield Fasteners Product Specification:

DIN 923 - Slotted Pan Head Screws with Shoulder

This product guide contains the specification for Slotted pan head screws with a shoulder, a series of standard parts available from Westfield Fasteners. The basis of this specification is the internationally recognised DIN standard DIN 923.

Product Description

Also known as stripper bolts, shoulder bolts or screws incorporate a wider diameter shank than the threaded part. This difference in diameter creates the shoulder against which the bolt is tightened, making them ideal as shafts for rotating bushings and bearings. They are also used to align components in assemblies, as pivots, guides, pins, linkages and trunnion mountings. This shoulder bolt design features a slotted pan head.

Dimensions for these parts refer to the shoulder; The diameter and length of the threaded section remains constant within each shoulder diameter. Shoulder screws include an undercut portion between the thread and shoulder, to allow a close fit.

Scope of the DIN Standard

DIN 923 details the form, together with the dimensions and tolerances for these slotted pan head screws with a shoulder. This standard includes thread sizes from M1.4 up to and including M10. See figure 1 and table 1 for this information.

Thread Size, d	p	b_e	d_k	d_s	k	n	r	t	v
nom	max=nom	min	max=nom	min	nom	max	min	nom	max	min	max	max	min	=
M1.4	0.3	2.2	3.50	3.32	2.000	1.975	0.9	1.02	0.78	0.3	0.50	0.36	0.10	0.60	0.45	0.25
M1.6	0.35	2.5	4.00	3.82	2.500	2.475	1	1.12	0.88	0.4	0.60	0.46	0.10	0.70	0.50	0.25
M2	0.4	3.0	4.50	4.32	2.800	2.775	1.2	1.32	1.08	0.5	0.70	0.56	0.10	0.80	0.60	0.30
M2.5	0.45	3.5	6.00	5.82	3.500	3.470	1.5	1.62	1.38	0.6	0.80	0.66	0.10	0.95	0.75	0.40
M3	0.5	4.5	7.00	6.78	4.000	3.970	1.8	1.92	1.68	0.8	1.00	0.86	0.10	1.15	0.90	0.45
M4	0.7	6.0	8.50	8.28	5.500	5.470	2.4	2.52	2.28	1	1.20	1.06	0.20	1.50	1.20	0.60
M5	0.8	7.0	11.00	10.73	7.000	6.964	2.7	2.82	2.58	1.2	1.51	1.26	0.20	1.60	1.30	0.70
M6	1	9.0	13.00	12.73	8.000	7.964	3.1	3.25	2.95	1.6	1.91	1.66	0.25	1.90	1.50	0.80
M8	1.25	11.0	16.00	15.73	10.000	9.964	3.8	3.95	3.65	2	2.31	2.06	0.40	2.40	1.90	0.90
M10	1.5	13.5	20.00	19.67	13.000	12.957	4.6	4.75	4.45	2.5	2.81	2.56	0.40	2.80	2.30	1.10

General Notes

The top edge of the head of the screw can be chamfered at 45 degrees or just rounded.
The tip of the screw thread is chamfered as in DIN EN ISO 4753.
The thread under cut, between the shank and the threaded part is manufactured to DIN 76.
The length of the incomplete thread at the tip of the screw (u) is the same or less than 1.5 times the thread pitch.

DIN 923 - Slotted Pan Head Screws with Shoulder

Figure 1: Slotted Pan Head Screw with Shoulder

Table 1: Dimensions & Tolerances (mm)