As I get a bit deeper into the machining of the second universal, using the A36 material, I'm not seeing a lot of difference in how it machines compared to the 1045 material. Possibly a bit more drag on an endmill when I'm backing out of a plunge cut, but not a big enough difference to worry about. I think that overall, there isn't a big enough difference in machinability between the two different materials to worry about.