Hi Tony,
When I cam to make the cam frames I decided to mill them from a solid piece of brass which resulted in a matched pair of frames with no gluing or brazing to make things go out of shape, and the wastage was quite small, but the end result worth it.
I also had questions about the cam timing as the copies of the drawings I had are very blurred and impossible to make out the comments so Jo, who is on this site as well, was good enough to forward me a photo version of the relevant page and I am assuming that the engine runs anti-clockwise when viewed from the side with the cylinder nearest the viewer.
1: with the con rod fully forwards, meaning piston at the top of the stroke, the widest part of the cam should be up pointing at 12 o'clock and should also be centred in the frames.
2: with the con rid fully backwards, meaning piston at the bottom of the stoke, the narrowest part of the cam should be pointing upwards at 12 o'clock and should also be centred in the frames.
3: when the cam drive rod knuckle is going towards fully up the cam should be turning anti-clockwise and pulling the frame back towards the flywheel.
4: when the cam drive rod knuckle is going towards fully down the cam should be turning anti-clockwise and pushing the frame forwards away from the flywheel.
If anyone else has built this engine and had it running perhaps they could comment on my interpretation of the cam timing so that we can at least try to get these two engines to run.
Mike