Hi Guys.
I noticed on my rotors during the development that the stud holes are slightly larger than the studs which shouldn't present a problem when the wheel is in place.
More of a concern is the rotor not centering on the axle flange. As the diameter of the spigot is smaller than the hole in the rotor hat it relies on the close machining of the axle flange to retain concentricity.
What is the inside diameter of your rotor hat - my genuine ones are 135.30mm and have a small step against the inside flange face.
One thing to note is that you may require a small chamfer on the edge of the axle as there may be a radius / step on the inside of the hat as mine have. This may not allow the rotor hat to sit flush against the face of the axle flange and not allow it to run true. This would make sense why the larger diam is still causing grief.
Maybe take a file and place a small chamfer (2-3mm) around the outside edge of the flange as shown in the pic below.
 

Hi all, thanks for your suggestions.

I think where I've gone wrong is either the protex discs have an ever so slightly larger inner diameter or my friendly machinist has been a bit tardy on his measurements! Probably a trap for amateurs like myself, perhaps I should have had the machinist start at say 136mm and worked his way down till it was a tight fit. Matt - do your axle flanges fit tight at 134.8mm?

There is no step on the inside of the disc, it's pretty much a right angle at the bottom. I don't have the tools to do an accurate measure of the inside diameter, but a rough tape measure measurement says 135mm to 136mm. I do like the idea of a sleeve on the axle centre, that sounds like it would do the trick nicely, otherwise I will have to start with a fresh set of axles to machine... Alternatively, could also try get my hands on the rda discs to see if they are a better fit.

Cheers, Aaron.

Hi Aaron
I had assumed that all the rotors would be identicle (silly me ) and in in hind sight it may have been a requirement to confirm the ID first prior to machining. 
Yes, the centre concentric ring would prob be the cheapest option.
The dimensions would be ;
Outside daimeter - 64mm
Inside diameter - 68mm
Thickness - 7mm.
I would also suggest a small chamfer on the inside edge of the centre hole to ensure a close fit with the flange face.
If you have difficulty getting them done for a reasonable price let me know and I'll see what I can do?
 
 

Hi Guys, I went down the path of having some sleeves machined and then press fitted to the axle hub. It's definately a good solution and centres the disc perfectly.  You should be able to just see the sleeve in this pic I have attached. Now to sort out that fiddly handbrake mechanism....