So having stripped the paint from Skarloey I've been looking at lots of photos of the original Talyllyn locomotive to work out what I need to alter to make the model look more realistic. One thing I did notice was that while the model has goal on top of the drivers side bunker this never appears to have happened in real life. In fact having looked at photos that show inside the cab it's clear that the reversing lever stands in front of the bunker meaning that even if it did store coal you'd never be able to get at it from inside the cab. Having spoken with one of the locomotives drivers (he's a fellow NGRM forum member) he confirmed that the bunker now contains the air brake equipment and before that was fitted it was just an empty space. So that means the coal had to go. Here is the casting before I started to do anything with it and you can clearly see coal both sides of the boiler.
My first, rather unsuccessful, attempt to remove the coal involved using a razor saw and files but it was impossible to remove much without the risk of damaging the rest of the casting. I was a little stumped until I realised that I could use the milling attachment for the lathe to cut it out. The downside was that I had to wait a few days for a 3mm milling cutter to arrive (I picked this one as I could get it quickly from Amazon without having to pay postage). I still don't own a machine vise or milling table though, so the casting was rather precariously held in the 3 jaw chuck bolted to the lathe bed.
In the close up photo you can see how little I'd managed to remove using a file before starting with the lathe. In the overall picture you can also see I've fitted a cheap swarf tray from the lid of a tub of Anchor spreadable that nicely fits between the feet of the lathe by the headstock. Not much use when milling though, but should catch most of the swarf when turning on the lathe.
I don't currently have anyway of setting the depth of cut with the milling attachment so made I set the depth by eye to make a number of passes each taking off a small layer of the casting. It took quite a while as the lathe can't be run continuously as the motor gets hot so I left it to cool between each pass. The other problem was that while I tightened the 3 jaw chuck properly it wasn't gripping much of the casting and with the way it over hanged the edge of the chuck it wasn't very stable. This means the cuts were not very level, and it did spin slightly at one point as well. All problems that would have been solved by a machine vice, but I'm still pretty happy with the result.
It's not pretty but it did the job and gave me practice of using the milling attachment and I'll be fitting a cover to the bunker, as on the loco currently, so the surface will be hidden anyway.