Spring Feet Revision

It was pointed out to me on the Busker Organ Forum, that the reservoir spring "feet" that I had made out of dowel pins had a couple of potential problems:

1. There was nothing to keep the dowels from sliding sideways and having the spring go flying out
2. A smooth dowel surface might be preferable to one with ridges like those on the dowel pins
3. Some sort of lubrication would be needed to keep the dowels from squeaking

With these things in mind, I revised the spring feet, making them more of a dumbbell shape so that they would not slide off the mounting blocks. I also filed a groove near the spring wire insertion hole so that the spring would not swivel sideways.

Here's a view of the new feet:

Here's how it looks in cross-section, using an off-cut scrap of the mounting block:

And here are the new feet - stained and in place:

One further revision…

Since the wood of the spring dowel feet squeaked a little when it rotated on the wood mounting blocks, I decided to put on a couple of drops of mineral oil for lubricant. This only made it squeak even worse.

To eliminate the wood-on-wood friction, I cut and split a couple of pieces of brass tubing and clipped them on the feet…. No more squeaks!

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!

Con Rods

Another little task for today…

I decided to tackle the con rods today, so I made some leather washers, cut some brass for the bellows connections, and sheathed some lengths of 1/4-28 threaded rod in brass tubing. For the front con rod, I put bent the tubing/rod piece and secured it into the rod end with a spring pin. For the straight shaft, I used some loctite and put  a bunch of contact cement into the tube before sliding it onto the rod so that it wouldn't rattle, hopefully…

I secured the bellows-to-rod connector pieces to the bellows using #4-1/2" screws, then attached the rods using the leather washers sandwiched between two nuts and a brass washer. Hopefully I can eventually replace the steel nuts with some made of brass, so everything in that area is the same color:

Here's an upside-down shot from a wider angle: