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Bonded Seals / Bonded Washers

Sealing Australia stocks a comprehensive range of bonded washers in British imperial and German metric standards.

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WHAT IS A BONDED WASHER?

A metal washer bonded to rubber, bonded washers (aka Dowty washers) are used to prevent leakage of media through fasteners of hydraulic fittings, pipe join flanges and valve bodies. A bonded washer consists of a flat metal ring with rubber bonded to the internal diameter that is wider than the metal washer. As the bolt or fitting is tightened, it compresses the rubber seal element until fully tightened upon the metal ring creating an efficient high pressure seal.
Bonded Washer

Bonded washers size list

Contoured back-ups are usually made of rubber and mimic the shape of an o’ring on one side to minimises distortion of the o’ring while under pressure.

Available in the following materials:

  • Mild Steel Self Centring NBR90.
  • Carbon Steel NBR70.
  • Carbon Steel Viton 70.
  • Stainless Steel Self Centring NBR70.

British Imperial Bonded Washers

Thread Size (M) InchThread size (M) BSPSize Reference(D) +0.13/-0mm(d1) ± 0.13mm(d) ± 0.13mm(S)Minimum Burst Pressure
(bar)
6BA0016.354.06 / 4.163.051.22 (+0.15/-0)2150
4BA0027.265.264.121.22 (+0.15/-0)1570
2BA0038.386.355.211.22 (+0.15/-0)1360
1/4″00413.218.006.861.22 (+0.15/-0)2430
1/4″00513.349.536.991.22 (+0.15/-0)1680
5/16″00613.349.538.311.22 (+0.15/-0)1680
5/16″00714.2210.048.641.22 (+0.15/-0)1750
3/8″1/8″ BSP02015.8811.8410.372.00 (±0.10)1480
.40″00818.3612.4511.262.00 (±0.10)1950
7/16″00919.0513.0811.692.00 (±0.10)1890
1/2″1/4″ BSP02120.5715.2113.742.00 (±0.10)1540
9/16″01022.2316.3914.862.00 (±0.10)1560
.60″02222.2317.3015.832.00 (±0.10)1290
5/8″01125.4018.7516.512.00 (±0.10)1560
3/8″ BSP02323.8018.7517.282.00 (±0.10)1230
11/16″01225.4019.6918.162.34 (+0.26/-0)1310
3/4″02426.9221.2119.692.34 (+0.26/-0)1230
13/16″1/2″ BSP02528.5823.0121.542.34 (+0.26/-0)1120
7/8″5/8″ BSP02631.7524.9723.492.34 (+0.26/-0)1240
15/16″01333.2726.0424.262.34 (+0.26/-0)1275
1″3/4″ BSP02734.9328.5327.052.34 (+0.26/-0)1050
1-1/16″02838.6130.6127.822.34 (+0.26/-0)1210
1-1/8″01436.5830.8629.332.34 (+0.26/-0)880
1-3/16″7/8″ BSP02938.1032.3930.812.34 (+0.26/-0)860
1-1/4″01541.4035.6932.643.25 (+0.26/-0)775
1-5/16″1″ BSP03042.8036.8833.893.25 (+0.26/-0)780
1-5/16″1″ BSP03142.8036.8833.892.34 (+0.26/-0)780
1-3/8″01644.4538.9935.943.25 (+0.26/-0)680
1-1/2″01747.7542.0438.963.25 (+0.26/-0)660
1-5/8″1-1/4″ BSP03252.3845.9342.933.25 (+0.26/-0)690
1-3/4″01857.1548.3945.343.25 (+0.26/-0)870
1-7/8″1-1/2″ BSP03358.6051.3948.443.25 (+0.26/-0)690
2″01963.5054.7451.693.25 (+0.26/-0)780
2-1/8″1-3/4″ BSP03469.8558.3054.893.25 (+0.26/-0)950
2-1/4″03570.3661.0958.043.25 (+0.26/-0)740
2″ BSP03673.0363.6360.583.25 (+0.26/-0)720
2-1/4″03777.7267.4464.393.25 (+0.26/-0)750
2-1/4″ BSP03879.5069.9866.683.25 (+0.26/-0)670
2-1/2″ BSP03990.1779.3876.083.25 (+0.26/-0)680

German Metric Bonded Washers

Thread Size (M)Size Reference(D) mm +0.13 / -0.00(d) ±0.10(d1) ±0.10(S)Min Burst Pressure (bar)
3.52017.24.15.21.0 (±0.1)1600
42027.04.55.41.0 (±0.1)1270
52039.05.76.81.0 (±0.1)1400
520410.05.77.41.0 (±0.1)1510
5.52059.26.27.21.0 (±0.1)1220
620610.06.78.01.0 (±0.1)1120
620711.06.78.21.0 (±0.1)1480
620811.06.78.22.5 (±0.1)1480
6.520912.07.18.81.0 (±0.1)1560
6.721010.27.38.61.0 (±0.1)850
821113.48.59.41.0 (±0.1)1780
821213.08.710.01.0 (±0.1)1330
821314.08.710.41.0 (±0.1)1510
821416.08.710.41.0 (±0.1)2150
8.521513.39.310.51.0 (±0.1)1200
1021616.010.3512.02.0 (±0.1)1470
1021716.010.712.41.5 (±0.1)1300
1021818.010.712.41.5 (±0.1)1880
1121916.311.412.71.5 (±0.1)1280
1122018.511.813.71.5 (±0.1)1540
1122119.111.813.51.5 (±0.1)1760
1222218.012.714.41.5 (±0.1)1150
1222320.012.714.41.5 (±0.1)1680
1322420.013.715.41.5 (±0.1)1340
1322522.013.715.41.5 (±0.1)1810
13.522618.714.015.71.5 (±0.1)900
1422722.014.716.41.5 (±0.1)1510
1522822.716.017.781.5 (±0.1)1260
1622924.016.718.41.5 (±0.1)1370
1723024.017.419.21.5 (±0.1)1150
17.523124.718.020.11.5 (±0.1)1070
1823226.018.720.41.5 (±0.1)1260
2023328.020.722.51.5 (±0.1)1140
2123428.721.523.32.5 (±0.15)1080
2223528.022.524.21.5 (±0.1)760
2223630.022.724.42.0 (±0.1)1080
2223730.022.724.43.0 (±0.1)1080
2423832.024.726.42.0 (±0.1)1000
2623935.028.426.72.0 (±0.1)1050
2724036.027.229.02.0 (±0.1)1130
3024239.031.033.02.0 (±0.1)870
3324342.033.735.82.0 (±0.1)840
3324443.034.336.42.0 (±0.1)870
3624546.036.738.82.0 (±0.1)890
3924651.040.041.92.5 (±0.1)1030
4224753.042.744.43.0 (±0.15)930
4824859.048.750.83.0 (±0.15)790
5124960.052.054.13.0 (±0.15)540
5225064.553.356.43.0 (±0.15)710
6025173.060.763.03.0 (±0.15)780
6825279.568.672.13.5 (±0.15)510
7525390.376.0879.13.38 (±0.15)700
88254101.4889.0992.13.25 (±0.15)510
125255143.67127.0132.75.0 (±0.15)420

Self Centring Stainless Steel Bonded Washers

Self centring bonded washers are essentially the same design as the standard Dowty type washers but include an additional non-sealing lip on the ID that locates the washer at the centre of a bolt hole without having to hold and manually locate washer while tightening fasteners.

Self Centring Bonded Washer

Self Centring Bonded Washers

Self centring range feature both metric and imperial sizes.
Thread Size (M)Size Reference(D) ±0.13mm(d1) ±0.10mm(d) ±0.13mm(C) Centring Lip(S) ±0.10mm
M886614.0010.408.706.401.00
1/8″ BSP82015.8811.8410.378.262.00
M1070816.0012.4010.708.051.50
M1286719.0014.1012.709.731.50
1/4″ BSP82120.5715.2113.7411.182.00
M1486822.0016.4014.7011.381.50
5/8″86925.4018.7516.5112.902.00
M1687024.0018.4016.7013.411.50
3/8″ BSP82323.8018.7517.2814.762.00
11/16″87125.4019.6918.1614.502.40
M1887226.0020.4018.7014.761.50
M2087328.0022.5020.7016.761.50
1/2″ BSP82528.5823.0121.5418.242.47
M2287430.0024.4022.7018.742.00
5/8″ BSP82631.7524.9723.4920.272.47
M2487532.0026.4024.7020.112.00
3/4″ BSP82734.9328.5327.0523.832.47
7/8″ BSP82938.1032.2930.8127.512.47
1″ BSP83042.8036.8833.8929.923.40
1-1/4″ BSP83252.3845.9342.9338.453.40
1-1/2″ BSP83358.6051.3948.4444.453.40
1-3/4″ BSP83469.8558.3054.8950.423.40
2″ BSP83673.0363.6360.5856.263.40
2-1/4″ BSP83879.5069.9866.6862.363.40
2-1/2″ BSP83990.1779.3876.0871.503.40

Bonded Washer Kit

Sealing Australia stocks a 280 piece bonded washer kit featuring popular metric and imperial sizes.

Bonded Washer Kit

Size ReferenceThreadQty
00410
00510
00610
01010
01210
0201/8″ BSP10
0211/4″ BSP10
02210
0233/8″ BSP10
02410
0251/2″ BSP5
0265
0275
0297/8″BSP5
0301″ BSP5
0311″ BSP5
203M510
206M610
212M810
215M8.510
217M1010
222M1210
223M1210
225M1310
227M1410
229M1610
232M1810
233M2010
236M225
238M245
239M265
240M275
242M305
243M335

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