Today I decided to turn the smokebox door from brass rod. I didn't have any hard dimensions to go by, so just estimated something from photographs. Here are a couple of photos of the workpiece in the lathe. I first drilled a 0.4mm hole in the end - this will take a piece of wire to hold the handles. I then had a go at forming the domed end. I didn't take a photo at that stage, so the first photo here shows me with a different tool installed that I have just used to remove the material behind the door, leaving a spigot. For this sort of operation I use a small parting tool that came with a holder to go in the tool post. I'm a bit of a novice with the lathe but find that this small, square-ended tool is often useful for 2mm scale turning operations, not only parting off.

At this point I determined that the door was still too thick, so I worked on the rounded end again to thin it down. This time I did take a photo, so you can see my setup for doing this. These kind of rounded shapes are quite easy to do by hand with a graver. I don't have a purpose-made tool rest (the Sherline one is crazily expensive), so instead am resting the graver on a length of tool steel held in the tool post.

Here's a picture of the graver - I got this a few months ago from https://www.eternaltools.com/carbide-gravers at the same time as ordering some piercing saw blades, and find it very nice to use. Certainly compared to the ground-down needle file that I used previously.

Here's the back of the door after cutting off. You can see the 0.4mm hole inside the spigot.

Then it was a case of soldering to the front of the smokebox, after first opening out the mounting hole. It turned out that this was no longer precisely in the centre (likely after my inadvertent repositioning of the smokebox front earlier), so I had to open out the hole further and position the door centrally by eye. Later in the day, after soldering this on, I looked at a different photo of the real thing and noticed that in Highland days that particular loco (at least) had a noticeable rim around the door. The picture I was looking at this morning didn't seem to show such a rim, so I hadn't included it in my turning. I think it is probably better now to leave it off rather than try to add it on untidily with wire or something. The hinges and handles/darts will be a task for another day.