Attaching rotors

[majel]

I am using MCG calipers and rotors for the first time on a car and I can not figure out how everything attaches to the axle. Now that I am not using the kit "drum" that snaps into the back of the tire how do I attach the rim to the axle without the use of lugnuts, and what do I use to fill that gap in the back of the tire where the drum used to be. I normally build box stock, and have never attempted this so please excuse my stupidity.

[Foxer]

Let me say something general, but the experts will be following me.

I'm just using some PE rotors for first time too. Most on my cars (have had no drum brakes since the rears on my TR4A 40 years ago) and the disks just bolt to a circular plate fixed to the axle. I just slid a circular hub/plate on the axle and glued. The only thing filling the inside of a rim nowadays is the disk brake. Some cars even have brake disks close to the center of the car next to the rear end. Usually the end of the axle consists of the brake disk with a heavy center that the wheel bolts to. The caliper is usually attached to the axle with a simple bracket. The model caliper is usually just glued to the disk unless you wanted to fabricate a bracket so the disk turns within the non-moving calipers as on 1:1 vehicles.