Reservoir Spring and Spill Valve Block

I wanted to tackle the reservoir spring and spill valve trigger block, so I did some measurements and made some pieces out of hardwood scraps. I bought the torsion spring from McMaster-Carr (catalog # 9271K113), so in order to get it ready, I bent the end tips with some vise-grips so they'd fit into their dowel "feet". For the dowel feet, I cut a pre-made wooden dowel pin in half, and drilled holes through the middle so that the spring wire would be a snug fit. I found that I had bent the tips of the wire a little long and they protruded through the dowel pieces. I figured that if I drilled additional holes in the scalloped mounting blocks, the tips of the spring wire would seat and center nicely - this didn't work very well, so I ended up trimming the wire so it didn't protrude through the dowels.

I also wanted to fancy up the spring itself a little, and since it was just a black oxide steel spring, I decided to give it a shinier brass finish using a technique I saw on YouTube a while back. Basically, the steel is heated up and then vigorously brushed with a brass wire brush. I used a brass wire brush wheel that came with my Dremel tool.

Next, I stained the wooden pieces, and while they dried, I prepared the mounting surface for gluing by sanding the finish off in specific places on the top of the reservoir and on the bottom of the pressure box.

I also wanted to secure the glued pieces with small screws, to serve as a clamp while the glue cures, as well as to add extra holding power.

So far I've used about 80 or so #2    3/8" slotted brass screws on this build. I really like this size and length as it provides nice holding power without having to go entirely through any of the plywood panels. I find that these screws really need a nice pilot hole in the plywood, but I always prefer to keep close control over the depth of the pilot hole, by "finger drilling" each one (twisting the drill bit between my thumb and forefinger). I usually put a small bit of tape on the drill bit to act as a depth gauge.

Here are both halves of the scalloped spring mount:

(This one also shows the spill valve block)

And here is what it looks like with everything in place and shellacked:

(Just in case the layout seems confusing -- ordinarily, the plans call for the spill valve to be located on the other side of the spring (toward the back of the organ by the bass pipes), but I wanted as much of the "inner workings" visible as possible through a top panel lid between the pressure box and the front pipes)


Just ordered a couple of rolls of music from Melvyn Wright (on the busker organ forum), and I can't wait until it arrives!