CNR 3737 :: Smokebox front

On Friday, Andy Malette hosted me for another work session on the CNR 2-8-2 project – and we tackled a major modification: the smokebox front.

New smokebox front

Our donor engines are USRA-designed light Mikados from Overland Models, which feature a smokebox front held in place with 20 dogs. Depending on the class of locomotive (and possibly the builder) Canadian National Railway steam engines featured either 10 or 12 dogs on the smokebox front.

We tend to notice these things, so it was obvious that the old dogs would have to come off and be replaced with new ones in the proper pattern. In this case, I would need 12 dogs – which means I couldn’t even cheat and simply grind away every other dog on the USRA smokebox front.

The Overland Models smokebox front is removable, but the dogs are cast as part of the face. So the easiest way to remove them was to turn them off on a lathe. I worked with very light passes, checking my progress frequently until I was happy with the results. After using the cutter, I finished up with progressively finer grits of sanding paper until all evidence of the dogs had disappeared. (This process also removed a portion of the hinges, but they will be relatively easy to replace with brass strip.)

Once the old dogs were gone, it was time to install new ones. Andy has some dogs cast by another friend of ours, but I would have to drill the smokebox face to accept them, then solder them in place. We moved the smokebox front from the lathe to the mill and added a 12-position indexer to evenly space the holes:

Index and centre drill

I started with a centre drill, then carefully drilled for the dogs, adding cutting oil for each hole. The last thing I wanted was a broken drill – Andy said he’s ruined a couple of smokebox fronts that way – and I’m pleased to report I drilled 12 perfect holes with no incidents.

Andy then locked the smokebox front in the vise and demonstrated how to solder these tiny dogs into place. He did the first one – I did the next 11. A minimal amount of flux, heating near – but not on – the dog, and a light touch with a thin length of solder on the side away from the heat was the key: Done right, the solder would melt onto the face of the smokebox than draw itself under the dog.

Here’s a composite photo showing the smokebox front, before and after the alterations:

Smokebox before and after

I think it was definitely worth the effort.

As part of this work session, I also added a drain pipe to the feed water heater, which I’d somehow missed during last week’s piping session. It’s the smaller pipe in this next photo, just ahead of the large exhaust pipe:

CNR 3737 Piping progress. Engineer's side front.

There are still a few details to address – including the various appliances that mount on the smokebox front. But I now feel confident that CNR 3737 is heading towards the paint shop this year. I’m really pleased with the progress made so far this month and look forward to the next session…

CNR 3737 :: The engineer’s side

After a hiatus for the holidays – and a month of avoiding the outside as much as possible due to heavy snow and bone-chilling cold in our part of the world – Andy Malette and I emerged like Wiarton Willie (a month late), saw our shadows, and decided it was time to continue working on the CNR 2-8-2 project.

At yesterday’s session, I turned my attention to the engineer’s side of the engine:

Piping - Engineer's Side

Here, I added some new piping, including the assembly in front of the cab and the angled pipe leading to the Hancock check valve on the top of the boiler, to the right (ahead) of the steam dome. I also reinstalled some piping under the cab and below the running board. And, I fabricated and installed the raised running board section that spans the power reverse unit.

For some reason – still a mystery to me – my soldering was much better today than it has been in the past. Maybe I’m finally getting the hang of this? I won’t inquire too closely – I’ll just roll with it, and keep doing what I’m doing. We’re having another session in a week, when I’ll tackle a project that will make major change to the appearance…