Chapter 27.1 – Boiler Jacket This week I’m moving on to the next section which covers the Boiler Jacket and the Handrails. And first up, is the Boiler Jacket. This, as the name implies, is a covering around the boiler to help minimize heat loss. In real life, this would cover additional lagging around the boiler. But in order to maximize the volume of the boiler, Kozo chose to skip any lagging and just go with the thin, mostly decorative, jacket.
I started by making a paper template of the boiler jacket. To be clear, this wasn’t because I doubted Kozo’s dimensions for the jacket, but rather, I worried that my boiler was out of dimension here or there and might require some customization.
After laying it out on a B-size sheet, I cut out the paper jacket with an X-Acto knife.
And fitted it up to the boiler. Turns out, all the holes line up as specified. Maybe I did a better job on the boiler than I thought!
There will be a little customizing of the hole around the steam dome due to my overly generous solder application. But I don’t want to even touch that area for fear of inducing a leak in my boiler
Having confirmed the design, I then cut a piece of 0.016” thick brass sheet (basically, 1/64”). Kozo specifies 0.012" sheet for the jacket but the thinnest I could source was the 1/64", so that's what I used. I roughed it out using a shear. Normally I’ve been using the bandsaw to cut sheet stock since the shear can deform the edges of the sheet. But this sheet was so thin I thought I could get away with the shear, which seems to have been the case.
Then I used the 2” belt grinder rotated on to its side to clean up the long edges of the cut and take it to the actual required size.
Then I laid out the features for the boiler jacket on the brass and used an optical center finder to find and mark all of the required holes.
I tackled the big holes first by using a circle cutter that is normally used for wood. This actually worked quite well. I kept the speed very low for this operation (like 150ish RMP). You can see the donut that was cut out of the center of the hole.
Then I drilled all the other holes. I used a step drill for the 3/8” holes. These were for clearance around the water inlets at the front of the boiler, and to make the rounded part of the back cut out as seen here:
Using a variety of tools (tinsnips, nibbler, and files) I cut the outside to shape.
And then bent the clamping edges over. Kozo gives a double thickness for the clamping flanges for added strength.
After the initial bend with the break, I used pliers to fold the edges over more and then a brass hammer to make a nice tight fold along the edge. Note that the center section between the two clamping tabs also has a folded edge.
I was going to finish this today but other things came up so I’ll complete it next time. Still to go are drilling the holes for the clamping screws, making the final bend for the clamping surfaces. And of course, the final fitting around the boiler!
Thanks for taking a look,
Kim
