Technical

Design

ACM composite marine bearings require radial support from the bearing housing. Under normal operating conditions the interference fit quoted is adequate to retain the bearing in its housing. The use of a retaining ring or a shouldered housing bore is recommended and a lead in chamfer is required on the bearing housing to prevent shaving of the bearing during press fitting.

The external diameter of the shaft should be constant over the length of the bearing operating surface. The surface finish should be a maximum of 1.2 Ra. For marine applications, ACM recommend a minimum standard of 316L stainless for the shaft material.

Machining

The material is readily machined using conventional machine tooling. Machining guidelines are available.

Installation

The bearings can either be pressed into the housing or freeze-fitted, depending on size. Freeze fitting with liquid nitrogen is the preferred method of installation for rudder and propellor shaft bearings. Care must be taken at all times not to damage the bush during the fitting process. Bore sizes must be checked along all axes at ambient temperature to ensure the minimum shaft clearance has been achieved.

Bearings can also be installed with the use of many of the two part epoxy chocking compounds currently available.

Composite Tubes