Hammer,pliers, hard surface and a prayer or two.
Actually they ARE really hard to get off.
Try this -
Remove the tyre (assuming the axle is NOT still on the car)
Wrap the wheel hub in thick but non compressing cardboard
Grip the wheel hard with some adjustable pliers and lock the axle into a vice or similar.
Give the hub a sharp twist or two in opposite directions and pull slightly along the plane of the axle.
This should free up the hub on the chamfered axle
HOWEVER! beware that this will ultimatley enlarge the internal hole so work may be required to refit it onto Ninco.
I have had some limited success refitting wheels to axles like this using thin double sided tape wrapped onto the axle end. But it tends to be luck whether the wheel is straight and balanced onto the axle afterwards. if running with mags this won't be a problem of course.
Good luck!

Actually they ARE really hard to get off.
Try this -
Remove the tyre (assuming the axle is NOT still on the car)
Wrap the wheel hub in thick but non compressing cardboard
Grip the wheel hard with some adjustable pliers and lock the axle into a vice or similar.
Give the hub a sharp twist or two in opposite directions and pull slightly along the plane of the axle.
This should free up the hub on the chamfered axle
HOWEVER! beware that this will ultimatley enlarge the internal hole so work may be required to refit it onto Ninco.
I have had some limited success refitting wheels to axles like this using thin double sided tape wrapped onto the axle end. But it tends to be luck whether the wheel is straight and balanced onto the axle afterwards. if running with mags this won't be a problem of course.
Good luck!