Machining axles - steel grade?
All,
I am looking in to machining some custom axles for a bike trailer. The long and short of it is I robbed the wheels/axles off an old kid trailer and they are 16". I can't easily find tires for that wheel size that will take high pressure (50+ psi). There are some odd-ball tires out there, but the other issue becomes the strength of the rim. So to alleviate all the nuances - I am going to upgrade to a 20" wheel set with traditional cone and race hubs (specifically front wheel hubs with disk brake mounts).
Therein lies the project. I need to make a stub axle that will allow a cone and race hub to mount to it.
The machining isn't an issue. I have access to every conventional type of machine under the sun.
The question is what to machine the axles out of.
There are likely 2 parts - the "axles" themselves and the "cones". I quote those because I don't think I want to use traditional off-the-shelf cones. There only needs to be threads on the outside. The inside can have a press-on cone that bottoms out. The cones need to withstand the pressure and abrasion of the bearing balls and the axle needs to be strong.
Why I don't think I can use off-the-shelf cones is I want to maximize the axle diameter. The limiting factor is the cone races - that there is enough material to engage the balls. What that allowable diameter ends up being I am not sure - maybe 13-14mm? I'll figure it out. I just don't think I can find a cone for over a 12mm axle. The other conundrum is there aren't press-on cones - they are threaded for conventional threaded axles.
Thoughts?