EMI Grounding Washers
Series 2500 (wire mesh) + 2600 (conductive elastomer) series
MAJR Products’ EMI grounding washers (2500 & 2600 series) are used in many military, SCIF, and industrial electronic enclosure applications. They are often installed under the head of bolts on shielded enclosure door hinges, door handle shafts and other bolt penetration points to aid in sealing and grounding of electronic noise. Our Grounding Washers are manufactured by either forming knitted wire mesh and compressing it into a close-tolerance forming dies or by CNC knife cutting the washer ID and OD out of a conductive elastomer material. Our EMI grounding washers can be supplied in various materials, diameters and thicknesses, for more information please see our product tabs below.
Wire Mesh Products
MAJR Products’ EMI grounding washers (2500 series) are manufactured from knitted wire mesh stocking that is formed into a resilient metal washer by compressing in a close-tolerance forming die.
The all-metallic construction of the EMI grounding washers that can be supplied in varying alloys makes them especially effective in hostile environments of temperature or chemicals.
Table 1 Grounding Washer Diameters
| Part Number | O.D. | I.D. |
|---|---|---|
| 250A-70005-xx | 0.218 | 0.062 |
| 250A-70007-xx | 0.375 | 0.250 |
| 250A-70009-xx | 0.030 | 0.000 |
| 250A-70010-xx | 1.000 | 0.500 |
| 250A-70015-xx | 0.234 | 0.109 |
| 250A-70020-xx | 0.500 | 0.250 |
| 250A-70027-xx | 0.635 | 0.500 |
| 250A-70076-xx | 1.120 | 0.810 |
| 250A-70078-xx | 0.906 | 0.593 |
| 250A-70084-xx | 1.370 | 1.120 |
| 250A-70092-xx | 0.750 | 0.228 |
| 250A-70094-xx | 0.062 | 0.000 |
| 250A-70106-xx | 1.425 | 1.043 |
| 250A-70108-xx | 1.437 | 1.063 |
| 250A-70110-xx | 1.437 | 1.102 |
| 250A-70115-xx | 0.255 | 0.150 |
| 250A-70117-xx | 0.885 | 0.625 |
| 250A-70118-xx | 0.630 | 0.550 |
| 250A-70119-xx | 1.380 | 1.250 |
| 250A-70120-xx | 0.380 | 0.250 |
| 250A-70121-xx | 0.880 | 0.810 |
| 250A-70122-xx | 0.635 | 0.375 |
| 250A-70134-xx | 0.937 | 0.687 |
| 250A-70135-xx | 0.625 | 0.469 |
| 250A-70136-xx | 1.620 | 1.125 |
| 250A-70137-xx | 2.130 | 1.600 |
| 250A-70144-xx | 0.875 | 0.375 |
| 250A-70145-xx | 0.345 | 0.185 |
| 250A-70150-xx | 2.125 | 1.812 |
| 250A-70158-xx | 1.500 | 1.000 |
| 250A-70160-xx | 2.950 | 2.875 |
| 250A-70180-xx | 0.910 | 0.790 |
| 250A-70200-xx | 0.750 | 0.250 |
| 250A-70310-xx | 0.410 | 0.250 |
| 250A-70320-xx | 0.350 | 0.175 |
| 250A-70350-xx | 0.906 | 0.344 |
| 250A-70360-xx | 0.550 | 0.200 |
| 250A-70500-xx | 0.875 | 0.344 |
| 250A-70501-xx | 0.875 | 0.315 |
| 250A-70502-xx | 0.275 | 0.180 |
| 250A-70503-xx | 0.300 | 0.150 |
| 250A-70504-xx | 0.240 | 0.187 |
| 250A-70600-xx | 1.370 | 0.750 |
| 250A-70650-xx | 2.625 | 0.450 |
| 250A-70700-xx | 0.500 | 0.200 |
| 250A-70710-xx | 0.450 | 0.170 |
| 250A-70720-xx | 1.250 | 0.315 |
| 250A-70730-xx | 1.880 | 0.680 |
| 250A-70740-xx | 1.000 | 0.300 |
| 250A-70750-xx | 1.800 | 0.480 |
| 250A-70755-xx | 1.100 | 0.315 |
| 250A-70756-xx | 0.900 | 0.480 |
| 250A-70800-xx | 0.394 | 0.323 |
| 250A-70950-xx | 1.375 | 1.125 |
Material Selections
Replace xx with the appropriate material code:
| XX | Material |
| 31 | Monel per QQ-N-281 Class A |
| 32 | Aluminum |
| 33 | Silver Plated Brass per QQ-W-321 (3% Silver by Weight) |
| 34 | Tin Plated Copper Clad Steel per ASTM B520 |
Note: *A = Thickness. Thickness needs to be specified at the time of request. *xx: See table 2 for material codes
Table 1 shows
washer sizes that can readily be supplied from existing tooling.
Thickness can be varied from .032 to .125.
Conductive Elastomer Products
MAJR Products’ EMI grounding washers (2600 series) are manufactured by cutting a specific ID and OD of the desired washer out of conductive elastomer sheet stock. The wide variety of mil-spec qualified elastomer materials with conductive fillers allows for superior galvanic compatibly options while the CNC cutting method ensures minimal setup costs and improved lead-times for new and custom sizes.
Flat Washers
| I.D +/- .015 |
O.D +/- .015 |
THICK T |
MIL SPEC M83528/012X-( ) |
MAJR PART NUMBER |
| .250 | .625 | 0.32 | (001) | 2603-025063-XX |
| 0.62 | (002) | 2606-025063-XX | ||
| .375 | .750 | 0.32 | (003) | 2603-038075-XX |
| 0.62 | (004) | 2606-038075-XX | ||
| .500 | .656 | 0.32 | (005) | 2603-050066-XX |
| 0.62 | (006) | 2606-050066-XX | ||
| .500 | .875 | 0.32 | (007) | 2603-050088-XX |
| 0.62 | (008) | 2606-050088-XX | ||
| .750 | 1.000 | 0.32 | (009) | 2603-075010-XX |
| 0.62 | (010) | 2606-075010-XX | ||
| 1.000 | 1.438 | 0.32 | (011) | 2603-100144-XX |
| 0.62 | (012) | 2606-100144-XX |
Material Selections
Replace xx with the appropriate material code:
| Conductive Elastomer Material Chart | |||||||||
| Material Designation Number | 52 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | |
| Elastomer | —— | Silicone | Silicone | Silicone | Silicone | Fluorosilicone | Silicone | Silicone | Silicone |
| Data Sheets | Data Sheet Link | Data Sheet Link | Data Sheet Link | Data Sheet Link | Data Sheet Link | Data Sheet Link | Data Sheet Link | Data Sheet Link | |
| MIL-DTL-83528 Type | —— | —— | M | A | B | D | L | E | —— |
| Material Description | —— | Ni/Gr | Ag/Glass | Ag/Cu | Ag/Al | Ag/Al | Ag/Ni | Ag | Carbon |
| Volume resistivity | Ohm-cm | 0.1 | 0.006 | 0.004 | 0.008 | 0.012 | 0.005 | 0.002 | 7 |
| Hardness | Shore A | 30-70 | 65 | 65 | 65 | 70 | 75 | 65 | 70 |
| Operating Temp. | Deg. C. Min. | -55 | -55 | -55 | -55 | -55 | -55 | -55 | -55 |
| Deg. C. Max. | 150 | 160 | 125 | 160 | 160 | 125 | 160 | 200 | |
| Conductive Elastomer Material Chart (continued) | ||||||||||
| Material Designation Number | 68 | 69 | 71 | 72 | 74 | 75 | 76 | 78 | 79 | |
| Elastomer | —— | Silicone | Fluorosilicone | Silicone | Fluorosilicone | Fluorosilicone | Fluorosilicone | Silicone | Silicone | Silicone |
| Data Sheets | Data Sheet Link | Data Sheet Link | Data Sheet Link | Data Sheet Link | Data Sheet Link | Data Sheet Link | —— | Data Sheet Link | Data Sheet Link | |
| MIL-DTL-83528 Type | —— | K | F | —— | —— | C | —— | I | H | G |
| Material Description | —— | Ag/Cu | Ag | Ni/Al | Ni/Al | Ag/Cu | Ni/Gr | Ag | Ag | Ag/Cu |
| Volume resistivity | Ohm-cm | 0.005 | 0.002 | 0.08 | 0.250 | 0.01 | 0.1 | 0.1 | 0.005 | 0.007 |
| Hardness | Shore A | 80 | 75 | 65 | 70 | 75 | 65 | 45 | 80 | 80 |
| Operating Temp. | Deg. C. Min. | -45 | -55 | -60 | -60 | -45 | -55 | -55 | -55 | -55 |
| Deg. C. Max. | 125 | 160 | 200 | 220 | 125 | 150 | 160 | 160 | 125 | |
Custom Product
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Data Sheet
Applications
Figures 1 through 4 show some of the possible mounting methods for grounding washers.
Figure 1
With Washer & Jam Nut
Figure 2
With Shaft Shoulder
Figure 3
With Positive Stop Cut Washer
Figure 4
Mounted In Flange Groove
