Here is how I did it:
First, center-drill all axles. After all, real locomotives are usually drilled, often all the way through. Choose a drill size that matches the diameter of some wire you have. For instance, .040 wire is the same size as a #60 drill.
Then lay out two aluminum plates - each will have the same size holes as your axles, spaced exactly as your axles. A trial fit with wire is next - make sure little pieces of your wire will go through the holes in the aluminum plate and into the holes in the axles.
Next step depends on the type of crankpins you have. Actually, once you have center-popped the plates for the axle holes you might want to draw partial circles around those punch marks at exactly the crankpin throw. Just think about that for a minute.
What you want is holes matching your crankpin diameter adjacent to those axle center holes - one plate will be drilled exactly in line with your center holes; the other will be drilled at right angles to that line.
press one side on the axles. Then pin the 90 degree plate with wire in the center holes and the crankpins in the larger holes. Secure the assembly so the pins won't drop out and place it on a flat steel plate with opposite axles up.
gently place the remaining drivers on the axles with crankpins lined up. Put the in- line plate on the drivers, insert the wires, and once all is set, press slowly, doing each driver a little at a time, pressing right at the axle pin on the aluminum plate.
A picture is worth a thousand words - let me know if that doesn't make sense. I think I published this in a Myron Biggar OGR.