Music Box Gong

Welcome to this edition of the Cotten Bros. Expositional Show of Mechanomorphic Wonders!

This instructable will give you the know-how to make a music box/gong/lawn ornament. It's entirely made of trash or discarded materials that is readily available to the savvy maker.

You will need:

1. A compressor tank (any size or shape will do)
2. About 12' of 2x6 (any wood, we used pine)
3. A 3'-4' 3x8 board
4. A long eye hook
5. One or two feet of wire (strong enough to hold the tank)
6. A large flat washer
7. Paint, in your preferred color
8. 6' of 1" angle iron
9. 14'' of 2x4
10. 3 bearings
11. Oak floor board scraps for the hammers
12. 6 small springs
13. Machinist nylon to fit the cylinder
14. About 3 1/2' of 1/4" metal rod
15. 2 Gears of equal size

Tools you'll need:

1. Side grinder with a 4" cut-off wheel and flap disk
2. 2" paint brush or roller
3. Assortment of hand tools
4. Hand drill with assortment of bits
5. Hacksaw
6. Handsaw
7. Crowbar
8. Metal lathe
9. Welder (we used a flux core welder from Harbor Freight)
10. Miter saw (optional)
11. Vise

Let's get started!

First up, cut all the unnecessary bits (a technical term) off with a side grinder. Then cut one of the narrow ends off, making a bell shape (fig .2). Finally, sand the tank with a flap disc on a side grinder (fig. 3) to eliminate rust and prepare for paint.

The paint we used in this project was salvaged from an old construction site. After priming with a strong, outdoor paint apply whatever colors or designs your wish. We used heavy duty latex-based paint, which sealed the tank without a need for lacquer or varnish. Make sure to apply plenty of coats, especially if your tank is rusted like ours as the rust will bleed through (fig. 3).

All the wood we used was salvaged from old barns, mostly left over from other projects. We cut a 2x6 into four sections, two measuring 2' long and the others 4' . We used the 4' sections as the side beams, and the 2' sections as the feet. We cut the corners off on the 2' sections so that they would be more pleasing to the eye when attached to the frame. Then, we nailed each pair of 2' and 4' boards together, making the t-shaped sides to the frame (fig. 5). A 3x8 piece of cypress was then shoe nailed (figs. 6-8) to the roof, attaching the two sides together. Thus, the frame was completed.

The tank hangs on an eye hook drilled in the top of the frame. Drill a hole in the center of the roof (unless you prefer an asymmetrical gong). Then, insert the hook in this hole, facing downwards and secure it. There should already be a hole in the top of your tank left over from its first life. This next part would be a lot easier with a friend to help lift the tank. Thread the large washer on a length of strong, thick wire (shown in fig. 3). Insert the washer and wire through the body of the gong- the washer should be larger than the hole, so it doesn't pass through it. Then, thread both ends of the wire through the hole and secure it to the hook by twisting or wrapping it around the hook. The gong should now be hung on the frame. Take a celebratory bash or three- you've earned it!

One particularly successful dump find of ours was an old trundle bed with angle iron on the sides. We used this for the sides of the frame housing the hammers, spindle and gears. The bed was riveted together, so we had to drill the rivets out (a dull and tedious process).

First up, we cut the 6' of angle iron from the bed in half. We also used a pair of 7" 2x4 scraps (these fit together and form the box around the complicated bits (as seen in fig. 1). You'll need to drill two holes in both of the 2x4s (fig 2). Sandwich the boards together in a vise and clamp as you drill your holes (figs. 3-4). The smaller hole is 1/4", and allows the rod holding the hammers to pass through (if your rod is a different diameter change this hole accordingly). The larger is 1/3", or to fit your crankshaft (see below). Only drill through the top board and about halfway through the bottom one. It is counter sunk to allow one of your bearings to fit snugly around the smaller hole. Our bearings came from an old computer mouse (fig. 8). Assemble the box (figs. 5-7) to resemble ours, seen in fig. 1.

The next step is to make the 6 hammers. The wood we used is oak flooring that had been lying around the shop for a long time. We made a paper pattern for all of them, although ours are all a little different in size.This was intended to make each sound slightly different, but it didn't work out quite as well as we had hoped. A bandsaw would help make this cutting easier, but we used a jigsaw. We then clamped a belt sander in a vise and sanded the hammers. Lastly, clamp the boards as you did the 2x4s in the previous step, and drill a 1/4" hole in each at the center of the thicker end to allow the rod to pass through. Next, cut spacers to place in between the hammers when you attach them to the rod. Size these to fit your rod and preferred hammer spacing.

We found a bit of 1 1/2" cast iron tubing and cut that to a little under 3 feet. This will form the body of the cylinder. Then we turned some machinist nylon on our metal lathe to make the end caps (figs. 1 and 2). Size these so they fit very snugly in the ends of the tubing. Take a bearing and drill a hole through one of the caps so that the bearing fits into it snugly (fig. 3). Cut and turn a pin to fit in the hole in the bottom 2x4 of the box assembled in step 7. Before removing the pin from the lathe, turn the end down so that the bearing in the lower end cap rests on the pin, but doesn't touch the board (fig. 5). The next step is the crankshaft (fig. 13). Take a piece of steel at least 2" long, and turn it so it fits through the hole in your second bearing. We were going to use a more fiddly system of bearings, so the pin seen in figs. 8-13 is turned more than necessary. Simply turn it to fit the bearing. After this, make a small 1/2" long pin and drill a hole 1/4" from the end of the shaft to fit this pin. Then drill a hole through the top cap to fit the crankshaft . Use a hacksaw to cut a groove in this so that the pin in the crankshaft can fit through (fig. 11-13).

This particular ''Thing'' is a piece of ancient farm machinery we cannibalized for gears. Taking it apart was simple for the most part. All we had to do was unscrew bolts and do a bit of old-fashioned prying. Any pair of identically-sized gears will work. We also cut a piece off of the axle to use as the gearshaft for the upright gear (fig. 3).

Next you'll need a bushing to fit over the crankshaft made in step 9 to serve as an adapter between the lower gear and the crankshaft. While this bushing needs to be sized to your gears, we used a piece of scrap aluminium with a diameter of 3/4" (the same diameter as the inside of the gear). Then center drill it on the lathe to fit your crankshaft. After you fit this on the shaft, drill a hole through the center side of the bushing and shaft. Fit and cut a pin to this hole, and the bushing is completed.

We then attached the music box to the frame made in step 4 with screws through holes in the angle iron (a super simple process). Next we took a piece of angle iron left over from constructing the frame (step 7) and the gears from the last two steps, and eyeballed their placement on top of the music box frame (fig. 1-2), drilling a hole for the top gearshaft based on our estimate. This piece of angle iron we then welded to the box frame (fig. 5). We discovered that the box needed an additional support on top to attach it to the frame and made this out of scrap iron, bending it with pliers and a vise.

The crank that we have was taken off of a dead old grain elevator (fig. 1) We welded it to a 2" long piece of piping with holes drilled in it for pins (fig.1-2) This was also off of the ''Thing'' we got the gears off of. We needed one of the pin holes to keep the crank attached, using a bent (and reused!) nail for a pin. Now to put it all together!

Assemble all of the pieces as per the pictures. The gears simply need to be fitted at the top of the cylinder and through the hole drilled in step 12. We attached springs to each of the hammers at the base with tacks, drilling holes through the angle iron at each hammer and sticking the spring's coil through these (fig. 2).

Once you've done that, weld prongs to the cylinder made in step 9 (fig. 3). These were made out of thick wire, although bolts attached using tapped holes would work as well. Take some care in arranging these in whatever pattern you want your gong to sound. To create different pitches for each of the hammers we wrapped them in different materials. Some examples are string (fig. 4), T-shirt material, or even a screw fastened in the tip of one (fig. 5).

It's finished!

We had to play around with the finished gong a bit to make it sound like an actual instrument, but overall, we're very happy with it. It was a fun project, and we wish you luck if you attempt it!

Edit- We've added a short video of the gong in action. Enjoy!

Happy building,

The Cotten Bros. Show of Mechanomorphic Wonders