both Phil and Viscount apparently both use a 6003 cartridge bearing (available at any bearing house, but you could buy them from Phil if you really want their "house brand" of bearing, they don't actually make the bearings). There are other plain spindles that might allow a press-fit in the ID of a 6003 bearing, Ritchey had a few and they might still be available from Icycles.com (and were very cheap, too). I haven't tried the fit of that combo so can't say. Spindles with an inner shoulder might not permit the bearings to seat completely in the Viscount BB shell: you'd have to try it out and see.