This picture shows the axle assemblies for one main ski getting ready to be welded to the steel "U" pieces. Note there is 2 additional side brace tubes to be weled from the base of each leg on the right hand assemby to the horizontal axle tube about 1" from the inside the left hand support tower. Once finished the complete assembly is cut into 2 sides about 2 inches from the left end of the horizontal axle tube making an axle assembly for each aluminium side rail. The 1/2" bolt is just to help show the location of the 16" long solid 4130 steel axle you make to mount the ski. The hollow centre of the Matco 0.75" axle allows for this axle bolt to pass through it length ...and through the solid aluminum gear spring (you drill it out first) to the attach to the inside rail of the ski. The front ski is simpler with shorter axle assemblies that use a longer AN5 bolt to attach the ski to the front axle of the CH701/750.