Originally Posted by
ultraman6970
Be careful with shimano because some of the 7 speed clusters aren't freewheels but cassettes. So look carefully.
The same is true of Sun Tour and Campy as they made 7-speed cassettes as well as freewheels.
I agree that there is too much axle stub sticking out of the drive side locknut. The correct protrusion is 5.5 mm on each end.
A 5-speed (120 mm OLD) hub will have an axle length of 131 mm measured from end to end (the entire axle, not the locknut face distance) and a 6/7-speed hub (126 mm OLD) will have a 137 mm axle length.