Mackay M135241 M12 Duro 40 BRB Flange Isolator - Xlarge
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The Mackay BRB flange isolator is an anti-vibration mount that works the rubber in shear and compression. Mackay says its tall profile gives large deflections, low natural frequencies and excellent vibration isolation, and that the range suits applications where isolation in the 85-95% range is a priority (manufacturer-stated).
This xlarge size has 8 variants in the store, rated from 200 to 475 kg, in Duro hardness 40 to 70. Each has a flange base 170 mm long with two mounting holes of 12.5 mm diameter (manufacturer-stated).
Where this product is used
- Isolating mobile rotating machines that are exposed to axial and radial shocks, dripping, diesel or oil, or the weather (manufacturer-stated).
- Mounting machinery where a high level of vibration isolation is required (manufacturer-stated).
- Replacing RAEM isolators: Mackay lists the BRB range as a replacement for them (manufacturer-stated).
Features
- Top metal hood protects the rubber from ozone, UV rays, diesel and oils (manufacturer-stated)
- Metal parts have an anticorrosive treatment suitable for outdoor use (manufacturer-stated)
- Interlocking metal component gives fail-safe protection in mobile applications by limiting upward vertical movement under shock (manufacturer-stated)
- Base is engraved with the type and hardness so the mount can be identified later (manufacturer-stated)
- Cross stamped on the hood adds rigidity in mobile applications and helps oils and liquids drain off (manufacturer-stated)
Common specifications
| Specification | Detail |
|---|---|
| Head diameter (A) | 106 mm |
| Height (B) | 41 mm |
| Mounting hole spacing D1 (min) / D2 (max) | 136 mm / 150 mm |
| Length (E) | 170 mm |
| Mounting hole diameter (F) | 12.5 mm |
| Base plate thickness (G) | 3.5 mm |
| Hardness range (Duro) | 40 to 70 |
| Load range | 200 to 475 kg |
| Weight | 0.85 kg each |
Key specifications
| Mackay part number | Hardness (Duro) | Load (kg) | Static deflection (mm) | Thread (C) | Weight (kg) |
|---|---|---|---|---|---|
| M135241 | 40 | 200 | 7.0 | M12 | 0.85 |
| M135242 | 50 | 300 | 7.5 | M12 | 0.85 |
| M135243 | 60 | 425 | 7.5 | M12 | 0.85 |
| M135244 | 70 | 475 | 5.5 | M12 | 0.85 |
| M135331 | 40 | 200 | 7.5 | M16 | 0.85 |
| M135332 | 50 | 300 | 7.0 | M16 | 0.85 |
| M135333 | 60 | 420 or 425 (catalogues differ) | 7.5 | M16 | 0.85 |
| M135334 | 70 | 475 | 5.5 | M16 | 0.85 |
Sizes A to G are Mackay catalogue dimensions in millimetres. Mackay prints all properties as nominal and asks you to contact them for technical advice. Static deflection follows the Mackay Vibration Isolators catalogue (Industrial Edition 09/2026); the earlier Industrial Rubber Technology catalogue prints different static deflection values for some of these part numbers.
Selecting the right option
Choose the part by load first, then by hardness: each part number in the table has its own load rating and Duro, so work out the share of machine weight each mount carries and pick the rating that matches. Then check the base against your supporting steelwork: hole diameter 12.5 mm, hole spacing 136 to 150 mm and overall length 170 mm. The other BRB sizes are linked below if your load falls outside 200 to 475 kg.
Related products
Other Mackay BRB flange isolator sizes: Mackay BRB Flange Isolator - Small, Mackay BRB Flange Isolator - Medium and Mackay BRB Flange Isolator - Large. Other Mackay flange isolators: Mackay Heavy Duty Flange Isolator M139 and Mackay Heavy Duty Flange Isolator M140.
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M12 / 200
Model Number: M135241
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M12 / 300
Model Number: M135242
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M12 / 425
Model Number: M135243
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M12 / 475
Model Number: M135244
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M16 / 200
Model Number: M135331
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M16 / 300
Model Number: M135332
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M16 / 425
Model Number: M135333
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M16 / 475
Model Number: M135334
