Bill,

It does not matter so much that the angle is exactly 90 degrees, it could be a few degrees either way, but each coupled wheel/axle set must be as close to exactly the same angle as possible.

In other words if one wheel set is quartered at 92.54 degrees, all coupled wheel sets should be quartered at 92.54 degrees.

Hope this helps.

JD

Hi Bill

Yes Jeff is spot onthe 90 degree is not important what is that all wheels are set the same. I use loctight and set the main axle by eye right hand leading, i make all the coupling rods but dont drill the vertical joints i make a simple jig a flat bar one hole and one slot and three bobins, one step to fit the axle bush the other the crank pin bush then set it to dead axle centres lock the rods to it and drill and reamer and fit knuckel pins, When all done set glue the wheels on axles put on the rods and bingo all done. I have always done it this way with no problems even on my 5" 9F with 5 axles.

Regards

Stan