How do I Dismantle Disc Hubs?

[antipodean]

Hey Guys,

A few years back when I started building my main ride, I realised that my red rims wouldn't last red for too long,
because I fitted the bike with derailleur gears and rim brakes.
However the cost of adding disk brakes was prohibitive at the time, so I decided that I would just repaint them at some point in the future
and keep an eye out for some disk brakes in the hard rubbish collection. As of this weekend I have finished my collection. I now have front and rear disk brakes, calipers and front forks. The only thing is the front wheel and forks are for 20 inch wheels, and my klunker has 26 inch wheels. The number of spokes are the same and the hub diameters look close enough, so I started dismantling my 20 inch rim. I got to the point as per the photo below, and figure I need to remove the bit that the rotor is bolted to. Can anyone tell me how I should remove this bracket? I need to remove it because otherwise I'll have to bend the spokes to get the old spokes out (no problem) and the new ones in (a problem).
How do I remove this thing? Is it threaded? Is it left or right hand thread? Do I need a special tool?
So far I've stuck it in the vice, sprayed a bit of WD40 on it and tried turning it with a large spanner, but to no avail. I don't want to damage the hub

Regards.

 

[ollyb83]

these tend to screw on anti clockwise, so when braking it tightens up rather than un-screws.

these can be udone by cmalping the adaptor in a vice and using the wheel to un-screw it.

 

[antipodean]

Thanks for that. It seems that the hub is a regular rear derailleur hub with this thing where the sprocket would otherwise be