Blimey! (puts thinking cap on)
I will try to do something soon then, but the easy thing would have been to photograph them as I went along even if the resulting image is tiny. Sadly I didn't do that this time.
If you don't mind having to use your imagination this time, then I can list how I put them together? I also expect that this is a rough draught of reality, omitting any aspects of profane language or despair.
In all cases I have a dimensioned drawing which comes from my CAD file for the model I am making. Of course a pencil sketch works fine.
I always keep the part held as part of the bar stock for as long as possible and keep the part as simple as possible in the sense that I will avoid adding parts unnecessarily if I am able to incorporate them as details turned or machined into the surface. That is not to say I am compromising on the detail level I choose, just reducing the chance of error or the number of processes or the possibility of the pattern disintegrating at some future time.
I make a 'blank' of the pattern which is the main body or simplest part upon which to attach the rest of the details and plan everything else around this.
For the valve guide, this is a cylindrical form which has the bolt detail holes and location for the valve slides drilled into the end using an indexing head. This is done on my Stevens 8mm milling machine, and the drills are shanked ones by Sphinx.
For these 4mm scale patterns, the bolt detail is 0.4mm wire soldered in with 188 solder paint. The bolt detail is then cut back with a file before putting back in my lathe for a few passes with a lathe tool to tidy them up. It is left oversized before the drilling so that the tiny drill is not given any opportunity to wander, after which the more or less final profile is done back in my lathe. I round the edges of the bolt detail off with a little cup shaped burr that jewellers use and this improves their appearance somewhat.
The main body was then cut from the bar stock.
The slides for the valve guide are an egg box construction from small etched parts. I could just as well have cut them from sheet, but etching seemed the obvious choice as much of the rest of the engine took advantage of this process. A tiny turning is also included for the gland. Small strips of material have been overlaid to thicken the pattern where the crossheads would run in real life, and are left oversized before dressing the ends of the slides to the final length
After assembly I ran the pattern in my lathe on it's mounting spigot and cut a miniscule groove where the steamchest front and cover meet, then carefully turned any build up of unwanted solder off the pattern and sharpened up any edges as I went. I am currently using a small abrasive mop type wheel and a fine automotive refinishing mat as a means to finish the surface prior to casting as casters always like to see shiney smooth patterns.
The whole pattern is 3% oversized, which on a CAD drawing is a very simple thing to do.
Well that's a start.
As a disclaimer, I am self taught which I hope can give others the sense that if you put your mind to things, then most things are possible.
Best regards
Tom