Not as much progress as hoped, I'm short the cylinder wrappers, fixing the front end and the stretcher flanges.
Today was frame overlays....twice!...don't ask and trailing truck. I'm jumping around the build a bit and not following the instructions or logical steps, primarily as the most important factor to resolve is the minimum radius.
I'd already heard that the trailing truck needs a tweak to go around 6' radius curves so I'd planned something different already, in short if I can get more play at the rear then I won't need so much at the front. Being as the front is tighter and more exposed visually then we need to keep that end as real as possible.
The problem with the trailing truck is it's width, I think it's designed for S7 and maybe even true scale width, the other issue is the wheels, the hubs are too fat and stop the outer wall of the trailing truck being moved inward.
The springs are not fitted yet but will be shortly, they're not essential at this point.
To cut a long story short I took 0.75 mm off the wheel hubs, they're fine and need to go on a diet anyway, plus the modification cannot be seen. This allows the outer plate work with the springs and axle box on to be moved in by 1.5 mm each side, there was an existing 1.0 mm gap before any modifications. By reducing axle side play to near zero you can reduced the gap to the tyre to around 0.3-4 mm with no shorts. The upshot is that the trailing truck is now 3.0 mm narrower, which allows for an extra +-1.5 mm throw. Is it enough
The 6' radius test curve.
It's close at the rear end and the width reduction has thrown up a new issue, previously it would of been the axle box or spring casting that would of impacted the inside of the frames, the springs still may' but at current guesswork...just. The reduction in width now allows the trailing truck to swing further and it's the outside wheel that is now going to impact the inner frame extensions. Some sort of stop will be required or I might epoxy a sacrificial nickel silver plate here and just let it touch, I'll probably do both.
At the front it's as expecting, it's not a true test as the bogie isn't there, there are no stops and there's still play in the main axles, even so, and taking all the factors into account, it's too close to relax and move on at warp speed.
I think it's safe to say that the inside cylinder floor will have to come out and the cut outs increased in depth by 1.0 mm; I'll also epoxy a sacrificial rubbing plate in there as well to isolate it electrically, in case of any unforeseen events that might cause a short.
MD