POINTS CAM REMOVAL/drive cog replacement

[arthur]

How do you get the cam off the spindle?
do I need to dismantle the entire assembly to remove the spindle from the bearing?
I am trying to replace the old broken drive cog but can't get things to move.
Is the nut on the inside a left hand thread? it would seem logical to me to be so ,then you could hold the outer nut still while removing the inner, and slide off the broken cog and pull the assembly out the front.
But I could do with a yay or nay before I break something

[arthur]

OK so had a look today the nut on the inside appears to be a normal thread as the nut from the outside threads on to the exposed threads of the inner shaft .
So how the hell do you hold the shaft fast to undo the inner nut?
the slot in the end is not ideal to wedge a flat screwdriver in

[arthur]

So thinking in for a penny in for a pound! and seeing as the original nylon part of cog was in bits I grasped the remaining metal part with a pair of grips ,fitted a socket on the nut and off she came ,removed the woodruff key and tapped the spindle outwards leaving the cam and propeller in situ jobs a good un!!
There is a bit of lateral play in the bearing this probably explains the cog exploding!!
I will replace it later here's hoping its not something special,
everyday is a learning day