Star hub reproductions that are equipped with tapered roller bearings require an uniform 11/16” axle center part. Harley Davidson axles for Star hubs (all Knuckles and Pans, SV Big Twins 1937-1966, 750 twins 1937-1951 rear, 1966 Shovels) have a center part with only the first 1-1/4” measuring 11/16” while the rest is reduced in diameter. On this reduced diameter a 11/16” Timken bearing will not fit, of course. On the other hand, a uniform diameter goes very well alongside with OEM star hub bearing sleeves, as these sleeves only touch the axle on their initial 3/4”. (The other side is borne by the brake side spacer.) Slight modifications may be required if you notice excessive wheel sideplay.