By Ramon Wilson
10. More ‘casting’ fabrication 
3. Cder

The exhaust has been kept simple - it can be extended then if required.

With that finished it was time to get on with the inlet. The original engine as designed by Anthony Mount had the inlet steam coming up through the centre of one of the columns through a cavity in the table top and up into the steam chest, the exhaust exiting by a similar route down another column. Whether this was true to prototype I have no idea but it does seem a rather good way to condense the steam before it gets to the steam chest

It was decided to fit a more conventional one that would hopefully look in keeping.

The upright was soldered up to save material.

The hole for the throttle bar was bored to ensure a good fit and concentricity. I've had the crude looking boring bar for the best part of forty years - its done countless bores over that period but gets thinner each time - a real favourite tool.
Tapping again - this time 12BA using a small piece of 1/8 brass tube - much better than relying on loosely nipped chuck jaws.
'Less haste more speed!' These two sides were 90degrees out of phase.
Fortunately there was enough left to come off the remaining sides to elicit a repair.
Cleaned up and parted off it's ready for the next stage. ‘Casting’ finish again applied with a Burgess engraving tool.
As mentioned previously the OD steam inlet valve was a might too tight.
But by reducing it's length and fettling a shade off the rear face plus a tad off the valve rod arm it just scrapes in. (This is at the bottom of the stroke)
It's even tighter here - haven't measured the gap but it's close. Wide enough, however.
The throttle rod, made from stainless was a devil to turn. Not particularly tough but bent all over the place as the stresses were relieved. Never considered it at the time but can stainless be stress relieved? Easily, at home, that is. It's not a material I am very familiar with in that quarter. With some judicious tweaking in the vice and a little applied science  it straightened enough to be acceptable and usable. It turns freely enough and there's an O-ring behind the end cover to help seal things.

See Part One here  - Part 2   Part 3   Part 4   Part 5  Part 6   Part 7   Part 8  Part 9 Part 10   Part 11 Part 12   Part 13   Part 14