Pretty sure the smokebox on 186 is just painted with matt black high-temperature paint. Same as all the other Whitehead locos.
I have a RAL swatch book, I'll try and see if I can get a match sometime, though it's difficult as the paint weathers and stains from cleaning (usually the dye in red diesel sometimes used as a degreaser at WDX stains the paint a little).
As a break from the 495 build, I decided to start on another locomotive.
This will be my first foray into complete scratch building and have chosen the ex DSER No. 52; 4-4-2T, GSR Class 458, as a starting point.
This loco class was long lived (1893 - 1955) and provided good service on the DSER section but given its life, it could reasonably appear in a wide variety locations and with different demands.
Photo courtesy of the "Good Book" (Clements & Mc Mahon)
I met with the good folk from the IRRS who were kind enough to give me access to the outline drawings which helped me develop up my own CAD drawings as an aid to building the loco. What is interesting is that while the IRRS drawings are dimensioned, they are not to scale, so some tweaking was required to get a more accurate drawing to work from.
First thing need were the frames. While it would be nice to create the frames in total (including the projection either side of the smokebox) it was easier to separate these into two sections. Once they are put on the footplate & mounted on the frames, it will make little difference.
This template was printed out and checked for scale before cutting (yes there was an earlier attempt!)
Two lengths of brass are tacked together, the template stuck down and cut with the piercing saw.
The result of much cutting and tidying up with files to get to this point.
I decided to compensate this chassis and am following the very good directions provided in Flexichas (Mike Sharman) who outlines the various methods of providing a fully compensated chassis.
In this instance, a primary compensation unit is constructed with fixed bearings able to pivot around a forward fulcrum, and balanced by the rear trailing wheels. What's nice about this is it's in the location of the firebox so seves two functions.
This unit was developed around the chassis drawing and was cut in a similar fashion to the main frames.
A few rivets along the bottom will provide the illusion of the firebox. This was then assembled to give:
This was inserted into the frames, the unit loaded into the locobox to set the hornblocks for the front driving axle. Lots of pegs etc were needed to get the frame and compensated unit to sit correctly before fixing in the hornblocks. 8'-6" coupling rods were used to set the distance and hornblocks soldered in.
From this starting point it was possible to set the trailing wheels and their respective hornblocks.
Some wheels were installed to get some idea of how the rear compensating unit will operate. At present a 1.5mm rod is located in the rear of the main compensating unit, which will pivot around the cross bar(?) which will then bear down on the trailing wheel axle. A vertical structure will be needed to make up the difference in height between these two units. Ride height can then be adjusted by tweaking the bar until the unit sits at the right height.
The main compensation unit will also provide a good location for the gearbox and motor which can be fixed to this unit.
Humble beginings, but a thoroughly enjoyable learning curve and looking forward to see how this turns out.
A good source of information, and inspiration, is "Scratch-Building Model Railway Tank Locomotives" by Simon Bolton. Excellent read, even if you are not going to build your own locomotive - he takes away the mystery (and fear) of scratch building and is certainly influencing me here.
Touched base with Chris in High Level and it turns out I have the wrong final drive gear - it should have 20 teeth, mine has 23, so new one on its way in the post.
Good time to put this one to one side for a short while and start something new.
Many thanks for that link - I got the book. That chap takes painting seriously!!! 😜
It'll take some time before I get to that level, if ever, but fascinating information none the less.