Product Description
Duramax rubber-lined naval brass bearings adapt equally well to strut and stern tube mounts, and are often used effectively as rudder-stock and pintle bushings.
- Duramax cutless bearings diameters are precision fitted - in accordance with U.S. Navy Buships clearances - to the designated shaft size with the correct clearance for efficient water lubrication
- Johnson-Duramax® bearings possess inherent vibration-dampening qualities and are non-polluting
- External brass shells are machined and polished to provide easy fitting
- Specially formulated oil and chemical resistant nitrile rubber is securely bonded to the shell
- Units with thin shells are available for the struts of small craft
- Sleeve bearings are usually installed by light press-fitting and locked in place with cone-pointed set screws
Johnson Cutless water-lubricated rubber bearings
have nothing more to prove.
More marine professionals have put their trust in Duramax Johnson Cutless Rubber Bearings than any other bearing in the world. Johnson Cutless is the original, true Cutless bearing, and is only available from Duramax Marine®.
The Cutless brand is the most recognized water lubricated marine bearing around the world. Our Johnson Cutless bearing was the first and continues to be the only bearing to meet all MIL-DTL-17901C Class II requirements.
Duramax Marine high quality standards, unmatched marine experience, and decades of water-lubricated rubber bearing research has resulted in performance records that other manufacturers only promise.
Designed for superior performance in the most demanding environments.
Johnson Cutless bearings are engineered with a proprietary formulation of extremely tough chemical and oil resistant nitrile rubber polymer lining, molded and firmly bonded into a naval brass or non-metallic shell. Grooves run the entire length of the rubber lining allowing for maximum lubricating water flow and dissipation of frictional heat.
Why Rubber?
Other reasons:
- The elastic properties of rubber allows grit and dirt to press into its surface until they are flushed out, protecting the shaft from scoring - unlike hard surface materials that can cause excessive shaft wear.
- Rubber is able to utilize any lubricants with low viscosity, such as water.
- When starved of water, rubber will not wipe or fail in a sudden catastrophic manner like hard surface materials. Rubber can crystallize but will always maintain its form.
- Each rubber landing area acts as an independent bearing surface.
- Rubber bearings always have contact area due to the elastomeric properties.
- Water-lubricated rubber has twice the specific heat of oil. An equal weight of water will absorb twice the heat of oil lubricants.
Rubber Water-Lubricated Bearings, The Environmental Solution.
Advantages of Rubber Properties In Water-Lubricated Bearing Design.
- The proprietary rubber formulation of the lined bearing is broken up by water grooves into a number of lands or faces. These surface lands run parallel to the shaft and serve in supporting it. A tough resilient rubber compound is selected which is relatively immune to the action of grit and sand and also helps reduce noise and vibration.
- When a grit is trapped between the shaft and the rubber, it is depressed into the landing's elastic surface and rolled into an adjacent water groove where it is immediately flushed out of the bearing.
- With proper loading, rotational speed and clearances, a water wedge is formed in the rubber landing causing the shaft to ride on a thin film that totally separates the shaft and bearing surface. This is known as hydrodynamic lubrication. At this juncture both friction and wear decrease significantly in a rubber bearing.
- Our proprietary rubber formulations have nothing more to prove. Rubber bearings are on more vessels around the world than any other material. Our Johnson Cutless Bearings have set unbelievable performance records that other bearing materials are still trying to meet.
