Reply to "How difficult is it to convert trucks to use roller bearings?"

I read this here with great interest. A recent restoration of a built 1939 Walthers wood kit that came with plastic trucks of unknown make leaves me with a car with applied breaks, so to speak. 

Here comes my question: When you do a conversion to ball bearing equipped journal boxes, what wheels or axles do you use? Are you using shouldered axles, like NWSL has them, or do you machine existing pointed axles? I don't have a mill. 

What's a convenient way to get axles that fit? I can fit FR133-ZZ flanged ball bearings in a plastic side frame of a freight car truck, works fine. Inner diameter is 3/32"

Thanks!