of example a typical size difference is an outer diameter of the first cylinder 20 around 0 1 mm greater than the inner diameter of the second cylinder 21 as the two cylinders 20 21 are cured separately and press fit together the interface 10 that is formed between them in the final product 1 is not a chemical bond but a purely mechanical bond interference fit the stresses that form in each of the two cylinders 20 21 during the curing process therefore do not transfer to the other cylinder 21 20 which reduces the risk of crack formation and delamination in turn this reduces the failure rate of the product 1 and increases the yield of the manufacturing process the interface 11 between the magnetically loaded composite mlc section 4 and the glass fibre gf section 3 is a chemical bond that is formed by polymeric crosslinking between the resin matrices of the two sections 3 4 this chemical bond forms during the curing process as these two sections 3 4 are cured together as the properties of the inner and outer sections 3 4 are sufficiently similar no significant stress gradient develops across this interface during the curing process fig2 a and 2.