Bonded/ Dowty Washers
Sealing Australia stocks a comprehensive range of bonded washers in British imperial and German metric standards.
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 washers size list
British Imperial Bonded Washers
| Thread Size (M) Inch | Thread size (M) BSP | Size Reference | (D) +0.13/-0mm | (d1) ± 0.13mm | (d) ± 0.13mm | (S) | Minimum Burst Pressure (bar) |
|---|---|---|---|---|---|---|---|
| 6BA | 001 | 6.35 | 4.06 / 4.16 | 3.05 | 1.22 (+0.15/-0) | 2150 | |
| 4BA | 002 | 7.26 | 5.26 | 4.12 | 1.22 (+0.15/-0) | 1570 | |
| 2BA | 003 | 8.38 | 6.35 | 5.21 | 1.22 (+0.15/-0) | 1360 | |
| 1/4″ | 004 | 13.21 | 8.00 | 6.86 | 1.22 (+0.15/-0) | 2430 | |
| 1/4″ | 005 | 13.34 | 9.53 | 6.99 | 1.22 (+0.15/-0) | 1680 | |
| 5/16″ | 006 | 13.34 | 9.53 | 8.31 | 1.22 (+0.15/-0) | 1680 | |
| 5/16″ | 007 | 14.22 | 10.04 | 8.64 | 1.22 (+0.15/-0) | 1750 | |
| 3/8″ | 1/8″ BSP | 020 | 15.88 | 11.84 | 10.37 | 2.00 (±0.10) | 1480 |
| .40″ | 008 | 18.36 | 12.45 | 11.26 | 2.00 (±0.10) | 1950 | |
| 7/16″ | 009 | 19.05 | 13.08 | 11.69 | 2.00 (±0.10) | 1890 | |
| 1/2″ | 1/4″ BSP | 021 | 20.57 | 15.21 | 13.74 | 2.00 (±0.10) | 1540 |
| 9/16″ | 010 | 22.23 | 16.39 | 14.86 | 2.00 (±0.10) | 1560 | |
| .60″ | 022 | 22.23 | 17.30 | 15.83 | 2.00 (±0.10) | 1290 | |
| 5/8″ | 011 | 25.40 | 18.75 | 16.51 | 2.00 (±0.10) | 1560 | |
| 3/8″ BSP | 023 | 23.80 | 18.75 | 17.28 | 2.00 (±0.10) | 1230 | |
| 11/16″ | 012 | 25.40 | 19.69 | 18.16 | 2.34 (+0.26/-0) | 1310 | |
| 3/4″ | 024 | 26.92 | 21.21 | 19.69 | 2.34 (+0.26/-0) | 1230 | |
| 13/16″ | 1/2″ BSP | 025 | 28.58 | 23.01 | 21.54 | 2.34 (+0.26/-0) | 1120 |
| 7/8″ | 5/8″ BSP | 026 | 31.75 | 24.97 | 23.49 | 2.34 (+0.26/-0) | 1240 |
| 15/16″ | 013 | 33.27 | 26.04 | 24.26 | 2.34 (+0.26/-0) | 1275 | |
| 1″ | 3/4″ BSP | 027 | 34.93 | 28.53 | 27.05 | 2.34 (+0.26/-0) | 1050 |
| 1-1/16″ | 028 | 38.61 | 30.61 | 27.82 | 2.34 (+0.26/-0) | 1210 | |
| 1-1/8″ | 014 | 36.58 | 30.86 | 29.33 | 2.34 (+0.26/-0) | 880 | |
| 1-3/16″ | 7/8″ BSP | 029 | 38.10 | 32.39 | 30.81 | 2.34 (+0.26/-0) | 860 |
| 1-1/4″ | 015 | 41.40 | 35.69 | 32.64 | 3.25 (+0.26/-0) | 775 | |
| 1-5/16″ | 1″ BSP | 030 | 42.80 | 36.88 | 33.89 | 3.25 (+0.26/-0) | 780 |
| 1-5/16″ | 1″ BSP | 031 | 42.80 | 36.88 | 33.89 | 2.34 (+0.26/-0) | 780 |
| 1-3/8″ | 016 | 44.45 | 38.99 | 35.94 | 3.25 (+0.26/-0) | 680 | |
| 1-1/2″ | 017 | 47.75 | 42.04 | 38.96 | 3.25 (+0.26/-0) | 660 | |
| 1-5/8″ | 1-1/4″ BSP | 032 | 52.38 | 45.93 | 42.93 | 3.25 (+0.26/-0) | 690 |
| 1-3/4″ | 018 | 57.15 | 48.39 | 45.34 | 3.25 (+0.26/-0) | 870 | |
| 1-7/8″ | 1-1/2″ BSP | 033 | 58.60 | 51.39 | 48.44 | 3.25 (+0.26/-0) | 690 |
| 2″ | 019 | 63.50 | 54.74 | 51.69 | 3.25 (+0.26/-0) | 780 | |
| 2-1/8″ | 1-3/4″ BSP | 034 | 69.85 | 58.30 | 54.89 | 3.25 (+0.26/-0) | 950 |
| 2-1/4″ | 035 | 70.36 | 61.09 | 58.04 | 3.25 (+0.26/-0) | 740 | |
| 2″ BSP | 036 | 73.03 | 63.63 | 60.58 | 3.25 (+0.26/-0) | 720 | |
| 2-1/4″ | 037 | 77.72 | 67.44 | 64.39 | 3.25 (+0.26/-0) | 750 | |
| 2-1/4″ BSP | 038 | 79.50 | 69.98 | 66.68 | 3.25 (+0.26/-0) | 670 | |
| 2-1/2″ BSP | 039 | 90.17 | 79.38 | 76.08 | 3.25 (+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) |
|---|---|---|---|---|---|---|
| 3.5 | 201 | 7.2 | 4.1 | 5.2 | 1.0 (±0.1) | 1600 |
| 4 | 202 | 7.0 | 4.5 | 5.4 | 1.0 (±0.1) | 1270 |
| 5 | 203 | 9.0 | 5.7 | 6.8 | 1.0 (±0.1) | 1400 |
| 5 | 204 | 10.0 | 5.7 | 7.4 | 1.0 (±0.1) | 1510 |
| 5.5 | 205 | 9.2 | 6.2 | 7.2 | 1.0 (±0.1) | 1220 |
| 6 | 206 | 10.0 | 6.7 | 8.0 | 1.0 (±0.1) | 1120 |
| 6 | 207 | 11.0 | 6.7 | 8.2 | 1.0 (±0.1) | 1480 |
| 6 | 208 | 11.0 | 6.7 | 8.2 | 2.5 (±0.1) | 1480 |
| 6.5 | 209 | 12.0 | 7.1 | 8.8 | 1.0 (±0.1) | 1560 |
| 6.7 | 210 | 10.2 | 7.3 | 8.6 | 1.0 (±0.1) | 850 |
| 8 | 211 | 13.4 | 8.5 | 9.4 | 1.0 (±0.1) | 1780 |
| 8 | 212 | 13.0 | 8.7 | 10.0 | 1.0 (±0.1) | 1330 |
| 8 | 213 | 14.0 | 8.7 | 10.4 | 1.0 (±0.1) | 1510 |
| 8 | 214 | 16.0 | 8.7 | 10.4 | 1.0 (±0.1) | 2150 |
| 8.5 | 215 | 13.3 | 9.3 | 10.5 | 1.0 (±0.1) | 1200 |
| 10 | 216 | 16.0 | 10.35 | 12.0 | 2.0 (±0.1) | 1470 |
| 10 | 217 | 16.0 | 10.7 | 12.4 | 1.5 (±0.1) | 1300 |
| 10 | 218 | 18.0 | 10.7 | 12.4 | 1.5 (±0.1) | 1880 |
| 11 | 219 | 16.3 | 11.4 | 12.7 | 1.5 (±0.1) | 1280 |
| 11 | 220 | 18.5 | 11.8 | 13.7 | 1.5 (±0.1) | 1540 |
| 11 | 221 | 19.1 | 11.8 | 13.5 | 1.5 (±0.1) | 1760 |
| 12 | 222 | 18.0 | 12.7 | 14.4 | 1.5 (±0.1) | 1150 |
| 12 | 223 | 20.0 | 12.7 | 14.4 | 1.5 (±0.1) | 1680 |
| 13 | 224 | 20.0 | 13.7 | 15.4 | 1.5 (±0.1) | 1340 |
| 13 | 225 | 22.0 | 13.7 | 15.4 | 1.5 (±0.1) | 1810 |
| 13.5 | 226 | 18.7 | 14.0 | 15.7 | 1.5 (±0.1) | 900 |
| 14 | 227 | 22.0 | 14.7 | 16.4 | 1.5 (±0.1) | 1510 |
| 15 | 228 | 22.7 | 16.0 | 17.78 | 1.5 (±0.1) | 1260 |
| 16 | 229 | 24.0 | 16.7 | 18.4 | 1.5 (±0.1) | 1370 |
| 17 | 230 | 24.0 | 17.4 | 19.2 | 1.5 (±0.1) | 1150 |
| 17.5 | 231 | 24.7 | 18.0 | 20.1 | 1.5 (±0.1) | 1070 |
| 18 | 232 | 26.0 | 18.7 | 20.4 | 1.5 (±0.1) | 1260 |
| 20 | 233 | 28.0 | 20.7 | 22.5 | 1.5 (±0.1) | 1140 |
| 21 | 234 | 28.7 | 21.5 | 23.3 | 2.5 (±0.15) | 1080 |
| 22 | 235 | 28.0 | 22.5 | 24.2 | 1.5 (±0.1) | 760 |
| 22 | 236 | 30.0 | 22.7 | 24.4 | 2.0 (±0.1) | 1080 |
| 22 | 237 | 30.0 | 22.7 | 24.4 | 3.0 (±0.1) | 1080 |
| 24 | 238 | 32.0 | 24.7 | 26.4 | 2.0 (±0.1) | 1000 |
| 26 | 239 | 35.0 | 28.4 | 26.7 | 2.0 (±0.1) | 1050 |
| 27 | 240 | 36.0 | 27.2 | 29.0 | 2.0 (±0.1) | 1130 |
| 30 | 242 | 39.0 | 31.0 | 33.0 | 2.0 (±0.1) | 870 |
| 33 | 243 | 42.0 | 33.7 | 35.8 | 2.0 (±0.1) | 840 |
| 33 | 244 | 43.0 | 34.3 | 36.4 | 2.0 (±0.1) | 870 |
| 36 | 245 | 46.0 | 36.7 | 38.8 | 2.0 (±0.1) | 890 |
| 39 | 246 | 51.0 | 40.0 | 41.9 | 2.5 (±0.1) | 1030 |
| 42 | 247 | 53.0 | 42.7 | 44.4 | 3.0 (±0.15) | 930 |
| 48 | 248 | 59.0 | 48.7 | 50.8 | 3.0 (±0.15) | 790 |
| 51 | 249 | 60.0 | 52.0 | 54.1 | 3.0 (±0.15) | 540 |
| 52 | 250 | 64.5 | 53.3 | 56.4 | 3.0 (±0.15) | 710 |
| 60 | 251 | 73.0 | 60.7 | 63.0 | 3.0 (±0.15) | 780 |
| 68 | 252 | 79.5 | 68.6 | 72.1 | 3.5 (±0.15) | 510 |
| 75 | 253 | 90.3 | 76.08 | 79.1 | 3.38 (±0.15) | 700 |
| 88 | 254 | 101.48 | 89.09 | 92.1 | 3.25 (±0.15) | 510 |
| 125 | 255 | 143.67 | 127.0 | 132.7 | 5.0 (±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 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 |
|---|---|---|---|---|---|---|
| M8 | 866 | 14.00 | 10.40 | 8.70 | 6.40 | 1.00 |
| 1/8″ BSP | 820 | 15.88 | 11.84 | 10.37 | 8.26 | 2.00 |
| M10 | 708 | 16.00 | 12.40 | 10.70 | 8.05 | 1.50 |
| M12 | 867 | 19.00 | 14.10 | 12.70 | 9.73 | 1.50 |
| 1/4″ BSP | 821 | 20.57 | 15.21 | 13.74 | 11.18 | 2.00 |
| M14 | 868 | 22.00 | 16.40 | 14.70 | 11.38 | 1.50 |
| 5/8″ | 869 | 25.40 | 18.75 | 16.51 | 12.90 | 2.00 |
| M16 | 870 | 24.00 | 18.40 | 16.70 | 13.41 | 1.50 |
| 3/8″ BSP | 823 | 23.80 | 18.75 | 17.28 | 14.76 | 2.00 |
| 11/16″ | 871 | 25.40 | 19.69 | 18.16 | 14.50 | 2.40 |
| M18 | 872 | 26.00 | 20.40 | 18.70 | 14.76 | 1.50 |
| M20 | 873 | 28.00 | 22.50 | 20.70 | 16.76 | 1.50 |
| 1/2″ BSP | 825 | 28.58 | 23.01 | 21.54 | 18.24 | 2.47 |
| M22 | 874 | 30.00 | 24.40 | 22.70 | 18.74 | 2.00 |
| 5/8″ BSP | 826 | 31.75 | 24.97 | 23.49 | 20.27 | 2.47 |
| M24 | 875 | 32.00 | 26.40 | 24.70 | 20.11 | 2.00 |
| 3/4″ BSP | 827 | 34.93 | 28.53 | 27.05 | 23.83 | 2.47 |
| 7/8″ BSP | 829 | 38.10 | 32.29 | 30.81 | 27.51 | 2.47 |
| 1″ BSP | 830 | 42.80 | 36.88 | 33.89 | 29.92 | 3.40 |
| 1-1/4″ BSP | 832 | 52.38 | 45.93 | 42.93 | 38.45 | 3.40 |
| 1-1/2″ BSP | 833 | 58.60 | 51.39 | 48.44 | 44.45 | 3.40 |
| 1-3/4″ BSP | 834 | 69.85 | 58.30 | 54.89 | 50.42 | 3.40 |
| 2″ BSP | 836 | 73.03 | 63.63 | 60.58 | 56.26 | 3.40 |
| 2-1/4″ BSP | 838 | 79.50 | 69.98 | 66.68 | 62.36 | 3.40 |
| 2-1/2″ BSP | 839 | 90.17 | 79.38 | 76.08 | 71.50 | 3.40 |
Bonded Washer Kit
Sealing Australia stocks a 280 piece bonded washer kit featuring popular metric and imperial sizes.
Bonded Washer Kit
| Size Reference | Thread | Qty |
|---|---|---|
| 004 | 10 | |
| 005 | 10 | |
| 006 | 10 | |
| 010 | 10 | |
| 012 | 10 | |
| 020 | 1/8″ BSP | 10 |
| 021 | 1/4″ BSP | 10 |
| 022 | 10 | |
| 023 | 3/8″ BSP | 10 |
| 024 | 10 | |
| 025 | 1/2″ BSP | 5 |
| 026 | 5 | |
| 027 | 5 | |
| 029 | 7/8″BSP | 5 |
| 030 | 1″ BSP | 5 |
| 031 | 1″ BSP | 5 |
| 203 | M5 | 10 |
| 206 | M6 | 10 |
| 212 | M8 | 10 |
| 215 | M8.5 | 10 |
| 217 | M10 | 10 |
| 222 | M12 | 10 |
| 223 | M12 | 10 |
| 225 | M13 | 10 |
| 227 | M14 | 10 |
| 229 | M16 | 10 |
| 232 | M18 | 10 |
| 233 | M20 | 10 |
| 236 | M22 | 5 |
| 238 | M24 | 5 |
| 239 | M26 | 5 |
| 240 | M27 | 5 |
| 242 | M30 | 5 |
| 243 | M33 | 5 |
See here for more seal kits and accessories.