Hole & Bar, Dimple Holes

Hole and Bar

Perforated holes and the space between them (referred to as “bars”) are produced by precisely machined punches penetrating a given material. While not visible to the naked eye, the top and bottom of perforated holes are not exactly the same. Dependent on the material type and thickness and the size of the punch, the force required to perforate material causes the punches to shear approximately the first 1/3 of it. As the punches continue to move downward through the material, the buildup of pressure causes the remaining 2/3 to eventually give way — resulting in a breakout, which is slightly larger and uneven.

Close-up cross-section of a typical hole

Dimple Holes

Close-up cross-section of a dimple hole

With the employment of special tooling and production techniques, holes can be indented slightly below the surface of the material. Providing a top side that is extremely smooth and a bottom side that is very rough, dimple holes are ideal for those applications where a typical hole may not be desired.

Generally an option only for round staggered and straight patterns, dimple holes are identified as such within the round hole portion of the perf pattern section. Because we are constantly developing new tooling and production techniques, if dimple holes are desired in a pattern where it is not shown as being an option, contact our customer service department and one of our representatives will check on our ability to produce what you want. Because dimple holes may vary in depth and slope depending on the material type and thickness and the size of the hole, required tolerances should be discussed with a sales engineer.

The table on the facing page shows the hole and bar tolerances for rounds and squares. They meet ASTM standard E 323, Specification for Perforated Plate Sieves for Testing Purposes.

			Tolerance on Openings				Tolerance on Average Bars
	Hole / Bar Width		Diamond Standard		Diamond Superior		Diamond Standard		Diamond Superior
	metric	standard	metric	standard	metric	standard	metric	standard	metric	standard
Round & Square	50.0	2	±1	±0.04	±0.13	±0.005	±1.4	±0.056	±0.18	±0.007
	—	1-7/8	-	±0.038	—	±0.005	—	±0.054	—	±0.007
	45.0	1-3/4	±0.9	±0.035	±0.13	±0.005	±1.3	±0.051	±0.18	±0.007
	———	1-5/8	———	±0.033	———	±0.005	———	±0.047	———	±0.007
	37.5	1-1/2	±0.8	±0.03	±0.13	±0.005	±1.1	±0.043	±0.18	±0.007
	———	1-3/8	———	±0.028	———	±0.005	———	±0.04	———	±0.007
	31.5	1-1/4	±0.6	±0.025	±0.13	±0.005	±0.9	±0.037	±0.18	±0.007
	———	1-3/16	———	±0.024	———	±0.005	———	±0.035	———	±0.007
	———	1-1/8	———	±0.023	———	±0.005	———	±0.034	———	±0.007
	26.5	1-1/16	±0.5	±0.021	±0.13	±0.005	±0.8	±0.032	±0.18	±0.007
	25.0	1	±0.5	±0.02	±0.13	±0.005	±0.8	±0.03	±0.18	±0.007
	———	15/16	———	±0.019	———	±0.005	———	±0.029	———	±0.007
	22.4	7/8	±0.46	±0.018	±0.13	±0.005	±0.7	±0.028	±0.18	±0.007
	———	13/16	———	±0.016	———	±0.005	———	±0.026	———	±0.007
	19.0	3/4	±0.38	±0.015	±0.13	±0.005	±0.6	±0.024	±0.18	±0.007
	———	11/16	———	±0.014	———	±0.005	———	±0.022	———	±0.007
	16.0	5/8	±0.32	±0.013	±0.13	±0.005	±0.5	±0.021	±0.18	±0.007
	———	9/16	———	±0.012	———	±0.005	———	±0.019	———	±0.007
	13.2	17/32	±0.3	±0.012	±0.13	±0.005	±0.46	±.018	±0.18	±0.007
	12.5	1/2	±0.28	±0.011	±0.13	±0.005	±0.44	±0.017	±0.18	±0.007
	———	15/32	———	±0.011	———	±0.005	———	±0.017	———	±0.007
	11.2	7/16	±0.28	±0.011	±0.13	±0.005	±0.41	±0.016	±0.18	±0.007
	9.5	3/8	±0.28	±0.01	±0.13	±0.005	±0.36	±0.014	±0.13	±0.005
	8.0	5/16	±0.26	±0.01	±0.13	±0.005	±0.32	±0.013	±0.13	±0.005
	6.7	17/64	±0.25	±0.009	±0.13	±0.005	±0.29	±0.011	±0.13	±0.005
	6.3	1/4	±0.25	±0.009	±0.13	±0.005	±0.28	±0.011	±0.13	±0.005
	5.6	7/32	±0.24	±0.009	±0.13	±0.005	±0.27	±0.011	±0.13	±0.005
	4.75	3/16	±0.21	±0.008	±0.13	±0.005	±0.23	±0.009	±0.13	±0.005
	4.00	5/32	±0.19	±0.007	±0.13	±0.005	±0.22	±0.009	±0.13	±0.005
	3.35	0.127	±0.17	±0.006	±0.13	±0.005	±0.20	±0.008	±0.13	±0.005