FITTING METALON BEARING
The dimensions of an METALON bearing will depend on how it is to be fitted. METALON bearings are most commonly press or shrink fitted. In this case interference and bore closure must be considered in the
dimension calculations along with running clearance, water swell and thermal allowances. If a bearing is to be bonded into the housing, however, then only the latter three factors need to be considered. The dimensioning of METALON bearings is different from that used with metallic bearing materials, and even for other non-metallic materials. These differences are due to the unique nature of the material, and must be considered in any application. When dimensioning an METALON bearing, the following parameters should be considered:
Housing size and tolerance, Shaft diameter and tolerance, Operating temperatures (maximum and minimum), Machine shop temperature, Type of lubrication, Retention method

INTERFERENCE
METALON Elastomeric bearings shrink on the outside and inside diameter as the temperature decreases. Due to the high co-efficient of thermal expansion (or contraction), it is necessary to allow for this factor when the operating environment drops below ambient. We assume machine shop temperature to be C in other parts of the
India, the ambient temperature may be different. In the following interference graphs, the cold environment allowance is based on the difference between minimum operating temperature and machine shop
ambient temperature. The graphs for POM and PA show increments of C for metric sizes each below machine shop ambient temperature. When freeze fitting METALON bush bearing, the selection of a suitable cooling agent depends on the temperature differential for which the s interference fit is designed. [Temperature differential is the difference between ambient machine shop temperature, typically C and the coldest temperature to which the installed bearing will be exposed.] If the differential is C or less, then Dry Ice can normally be used. If the differential is greater than C the use of liquid Nitrogen is recommended.

BORE CLOSURE
When an METALON bearing is installed with an interference fit, the inside diameter of the bearing contracts due to volumetric displacement. The exact amount of bore closure will vary with the type of finish tolerance on the housing and the bearing, approximations by thumb rule can be applied. Actual testing in a given situation, if required, can be developed more precise figures. Note that, due to the lower coefficient of friction of METALON-OILON, its maximum bore closure is only 125%. Bore closure is expressed as a percentage of maximum interference.

THERMAL EXPANSION ALLOWANCE
The thermal expansion allowance “ Te" must be considered when the maximum operating temperature exceeds the machine shop “ ambient , “ Te" is based on the coefficient of thermal expansion of METALON. The formula is as follows : 
Te = 2w x þ x (To-Ta)
Te = Thermal expansion allowance
W  = Wall thickness
     = Coefficient of thermal expansion of the selected METALON grade
To = Maximum operating temperature
Ta = Machine shop ambient
Te AXIAL
WATER SWELL
When immersed in water. METALON swells 0.6% under normal conditions. (23^oC or less) Some of this expansion simply increases the amount of interference, but there is also an effect on the inside diameter of the bearing. The normal diametric water swell “ C"  calculation is: C = 0.011 x wall thickness. METALON swells slightly more in warm water. For critical applications the closure factor will change as the water temperature changes. If the water temperature is higher than 40^oC, C= diametrical closure factor x wall thickness.

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