Here is my attempt based on the blueprint and photos of the 999 engine I found on the web. These of course are the small truck wheels and not the large drive wheels.

The blueprint with just the one view is not enough information, but I hope I came close.

The original question was about getting the entire wheel to boolean into a solid. I had no issues with that, or with adding a fillet around the 12 spokes.

We would need to see your 3DM file to help out.

Ed Ferguson






Curves used to make the wheel: