a silver coating 81 can also be provided on top hat bushing 50 to enhance compressibility as well as to lubricate the interface of the annular bearing surface 74 of top hat bushing 50 with annular end bearing surface 76 in cavity 54 while the structure and manufacturing method described above is currently believed to provide the most effective axial force distribution it is certainly feasible as an alternative to machine the cavity 54 in a manner that is calculated to cause initial contact between the annular bearing surface 74 of top hat bushing 50 and the annular end bearing surface 76 in cavity 54 before the annular inside bearing surface 72 of race channel 49 and the inside end surface 78 of cylindrical bushing 44 contact each other for example the cavity 54 of cutter wheel 10 could be machined to cause initial contact between the annular bearing surface 74 of top hat bushing 50 and the annular end bearing surface 76 in cavity 54 when the annular inside bearing surface 72 of race channel 49 and the inside end surface 78 of cylindrical bushing 44 are still separated by about 0 001 to 0 002 inch instead of the other way described above either way the initial wearing in or seating in combination with the silver coating 80 and optionally silver coating 81 provides a durable long lasting axial thrust bearing arrangement between the cutter wheel 10 and the spindle 40 the lateral force components f l as mentioned above are borne by the spindle 40 primarily on the cylindrical bearing surface 70 of race channel 49 where the inside cylindrical surface 82 of cylindrical bushing 44 interfaces with and spins in relation to the spindle 40.