Suggested Hole Sizes

Elgin Fastener Group threaded fasteners, machine screws and small diameter fasteners are available in various sizes, threads and diameters. The chart below lists the suggested hole sizes for die casting.

The minimum length of thread engagement should be equal to twice the diameter of the screw. The hole diameter, to ensure optimum performance, should provide for 65% to 75% thread engagement.
Screw  Size	HoleDiameter as Cast Std. Taper				F Hole Dia. as Drilled	L Length of Thread Engagement	H Boss Dia. Max.	J Distance to Edge for no Measurable Distortion – Min.
	A– Top		B– Bottom
	Max.	Min.	Max.	Min.
M2x 0.40	1.91	1.83	1.81	1.73	1.81	4.00	3.32	1.04
2-56	.081	.078	.077	.074	.077	.172	.197	.046
M2.5×0.45	2.39	2.31	2.28	2.20	2.28	5.00	4.15	0.55
3-48	.093	.090	.088	.085	.088	.198	.208	.054
M3x0.5	2.90	2.82	2.76	2.68	2.76	6.00	4.98	0.61
5-40	.118	.115	.112	.109	.112	.250	.232	.065
M3.5×0.6	3.31	3.23	3.21	3.13	3.21	7.00	5.81	0.74
6-32	.128	.125	.122	.119	.122	.276	.242	.081
M4x0.7	3.82	3.74	3.64	3.56	3.64	8.0	6.64	0.86
8-32	.155	.152	.148	.145	.148	.328	.272	.081
M4.5×0.75	4.31	4.23	4.11	4.03	4.11	9.00	7.47	0.92
10-24	.177	.174	.168	.165	.168	.380	.315	.108
10-32	.182	.179	.174	.171	.174	.380	.315	.081
M5x0.8	4.8	4.72	4.58	4.50	4.58	10.00	8.30	.098
12-24	.203	.200	.194	.191	.194	.432	.359	.108
M6x1.0	5.75	5.66	5.48	5.40	5.48	12.00	9.96	1.23
M6.3×1.0	6.05	5.97	5.78	5.70	5.78	13.00	10.46	1.23
1/4-20	.235	.232	.224	.221	.224	.500	.415	.130
M7x1.0	6.78	6.70	6.48	6.40	6.48	14.00	11.62	1.23
5/16-18	.267	.294	.284	.281	.284	.625	.519	.144
M8x1.25	7.69	7.61	7.32	7.27	7.35	16.00	13.28	1.53
3/8-16	.359	.356	.343	.340	.343	.750	.623	.162
M10x1.5	9.64	9.56	9.22	9.14	9.22	20.00	16.60	1.84
7/16-14	.419	.416	.400	.397	.400	.875	.726	.186
M12x1.75	11.59	11.51	11.09	11.01	11.09	24.00	19.92	2.15
1/2-13	.481	.478	.460	.457	.460	1.00	.830	.200