Giant PVC Music Box

This project is like a music box in that a spinning drum plays a tune, but unlike a music box, it is large and creates sound with pipes rather than strips of metal. It also is powered by pushing the drum (directly, or with an optional handle), whereas in a music box, a would-up spring would supply the power. Due to the difficulty in obtaining extremely wide, short cylinders, a 5-gallon bucket is used as the drum, limiting the length of the song that can played--depending on the speed at which the drum is spun, a melody repeats about once every 2 seconds.

To build this project, you will need a chop saw and general drilling equipment. The only unusual tool you will need is a hole saw with a diameter of 2.375in (2.5in will also work). You will also need:

• 120in of 40 schedule PVC pipe with a 2in diameter.
• 2 pieces of plywood that are at least 6in in length and 13in in width (preferably, all plywood should be at least 0.25in in thickness unless otherwise noted)
• A plywood board with a width of at least 12in and a length of 15in
• two squarish posts about 12in long and 1in wide
• Eye-hooks (optional)
• 5 small hinges
• 5 2.25in by 8in boards
• Flips flops or other comparable rubber
• 5 Rubber bands or springs
• A 5-gallon bucket with lid
• 60in Wooden dowel (or shorter dowels totaling around 60in) at least 0.75in in diameter
• A sturdy metal rod at least 20in long
• A hollow container slight shorter than the bucket in both dimensions
• A bag of cement
• A plywood board with a minimum length and width of 20in and a minimum thickness of 0.5in
• About 48in of 2 by 4
• Two bearing sets designed to bear radial load (force perpendicular to the axis of rotation)
• Screws

Note that some instructions may not exactly match the pictures provided (for example, we did not use a bucket lid but recommend that you do). This is because we modified our design so that you can avoid some minor mistakes that we made in the planning process.

Please read all the instructions before beginning; if anything is unclear, this will help you to deduce what is meant.

If you would like to paint any part of your project, it is easiest to do so before assembly.

Obtain about 120in of 40 schedule PVC pipe with a 2in diameter.

Use a chop saw to cut PVC at different lengths that match desired notes for song.

The lengths we used were 35in, 28in, 23in, 17in, 14.5in but keep in mind that these are not completely accurate and are intended to leave room for tuning. The longest PVC is the root (approximately an F#) and the rest are a major third, perfect fifth, octave, and major ninth.

Obtain a piece of plywood that is at least 6in in length and 13in in width (preferably, it should be at least 0.25in in thickness). Mark 5 2.375in (ideal) or 2.5in circles along one long edge at evenly spaced intervals and about 0.25in from the edge of the wood and mark 5 additional 1in circles 0.5in from the back of the larger holes.

Create holes by removing all the area inside the circles you marked. You can do this by using a 2.375in hole saw, a 2.5in hole saw (if a 2.375in hole saw in unavailable), or a large drill bit and multiple passes. The external diameter of a 40 schedule 2in PVC pipe is 2.375in, so aim for this diameter. The 1in holes are for rubber bands or springs you will attach later.

Once you have prepared your first piece of plywood, create a duplicate different only in that instead of 1in holes, there is something in the same spot to attach rubber bands or springs to. We used eye-hooks. Use a piece of plywood and two boards with roughly square ends to separate the two plywood sheets at a distance of about 1in shorter than your shortest PVC so that they are parallel to each other. You may need to use small blocks in the joints in the back if your plywood is too thin to accept a screw (this is what we did).

The plywood that you use on the back must be long enough to support the flaps so that they can evenly strike the bottoms of the PVC. Create these flaps with a width of 2.25in and a length of 0.5in longer than the short side of your plywood with holes (the flaps should be able to stick past the edge of this plywood). Glue circles or squares with a width of 2.25in made of some rubbery material such as a flip flop 0.5in from the edge of each flap, and if possible, create a recess so that these pads can lie flush with the flaps (we used a table saw with the blade set low, but a router could work too). Use small hinges to attach the flaps to the plywood back about 0.5in below the lower plywood board (the one with 10 total holes) so that the flaps can move freely to strike the PVC when you install it. Create points to attach rubber bands or springs to each flap about 0.5in away from the edge of the pads (once again, we used eye-hooks). Attach rubber bands or springs to connect the flaps and the top of the frame so that when pulled downwards, they spring back up.

Obtain a plastic 5 gallon bucket with a lid, wooden dowels (at least 0.75in in diameter), a sturdy metal rod (at least 20in long), a hollow container slightly shorter and less wide than your bucket, and cement.

To prepare the bucket for the axle (the metal rod), drill holes large enough to accommodate the rod in the center of the bottom of the bucket, its lid, and in the center of both ends of the hollow container.

To prepare the bucket for the dowels, begin by drawing a grid onto the exterior of the bucket (we drew with a sharpie). The grid should be composed of 24 evenly spaced, vertical lines around the bucket and 5 rings up the length of the bucket. These rings should be spaced so that when the bucket is held horizontal next to the PVC frame, the rings line up with the centers of each hole. After you have drawn the grid, you will need to mark which intersections will have a dowel. To use the song we used, decide which vertical line will be the beginning and mark its intersection with the ring you drew closest to the wider end of the bucket. Then mark the remainder of the intersections by following the music we provided as an attachment. Each vertical line on your bucket corresponds to an 8th note and each ring corresponds with the 5 notes in the music (if you are not familiar with written music, read this page: https://www.musicnotes.com/blog/2014/04/11/how-to... You can also write your own song.

After drilling guide holes in each intersection you marked, drill holes large enough to accommodate the diameter of your dowels. If you don't have a drill bit large enough, you can enlarge the holes with a file (it also helps to have a tight fit for when you pour cement into the bucket). Cut your dowels into 2in segments (you should have as many segments as you have holes drilled) and place the segments into each hole so that their ends are all the same distance from the axle (do not insert them the same distance into the side of the bucket; because the bucket is not perfectly cylindrical, this will result in some pegs being too far from the flaps they are meant to hit).

When the axle and dowels have been placed, place the assembly vertically on blocks with a height of about 2in so that the axle can extend 2in below the bottom of the bucket. Then mix and pour a bit of cement into the bottom of the bucket around the axle and lowest dowels. Place the lid around the axle and snap it to the top of the bucket and allow the cement to dry until it is somewhat firm but still wet (this will help ensure that the axle is straight). Then place the hollow container around the axle and push it down to the drying cement and pour the remainder of the cement to fill the bucket up to the lid before securing the lid with glue to the top of the bucket. Before the cement dries, make sure all the dowels are perpendicular to and equidistant from axle (you will have some time to adjust them before the cement is hard). Allow the cement to dry for at least the recommended time before attempting to lift the bucket, and do not remove the bucket from the blocks that support it. Be sure to clean any cement that may have escaped from the holes.

When the cement has dried, drill guide holes in the center of each dowel and screw in either screws or eye-hooks. They should not be screwed in all the way, and by adjusting their depth you can calibrate the length of each protrusion.

Obtain a plywood board with a minimum length and width of 20in and a minimum thickness of 0.5in, about 48in of 2 by 4, two bearing sets designed to bear radial load (force perpendicular to the axis of rotation), and plenty of screws. Any additional wood you have access to may be useful for reinforcing the drum frame.

Start by setting your bearings into the 2 by 4. Cut two 11in segments of 2 by 4 and drill holes centered 10in from the bottom of the wood with a diameter large enough to accommodate your bearings. Make sure that the holes are in the same place on each board. After glueing the bearings into the holes (and ensuring that no glue comes in contact with any moving part of the bearing!), screw the 2 by 4s into the large plywood board so that they are parallel, span a width slightly larger than the height of the bucket, and are in line with the edge of the board. Remove one of the 2 by 4s, place the axle of the drum into both bearings, and screw the 2 by 4 that you removed back in place. Make any reinforcements to this structure that seem necessary (this could be a metal L-bracket, for example). At this point, the drum should be able to spin freely.

Glue each PVC into the frame in order of length with the longest PVC on the left and the shortest on the right (any glue that expands and adheres to both wood and PVC will be ideal--we used Gorilla Glue). If your hole saw was too large, wrap the PVC in tape where it will meet the frame to fill the space. Before allowing the glue to dry, make sure that the PVCs are aligned so that the flaps strike the bottoms completely squarely and flatly.

After the glue dries, use the remainder of the 2 by 4s from the previous step to suspend the PVC frame and PVCs so that they are perpendicular to the base of the drum frame and so that the protrusions (dowels with screws) from the bucket will barely catch the flaps as the drum spins. If any protrusion does not catch or is too long, turn the screw to adjust the length of the protrusion. How you suspend the frame depends on the wood available to you and the specifics of your frames, but anything will work as long as the protrusions catch and everything is stable. We screwed segments of 2 by 4 to the solid wood of the PVC frame and screwed the ends of the 2 by 4s to the base of the drum frame.

At this point, you should be able to spin the bucket towards the PVCs so that the melody is produced. You can stop here, or you can add a handle with which to spin the drum. We did this by screwing a paint stick into the axle, but there are many ways you could add a handle. You could even use a pair of bike pedals!

Have fun with your new instrument, and feel free to comment any changes you made