GuyK
Addicted Member
After pondering the Ed Schilling Bucket Sub for awhile, I think I've reached some conclusions as to why it seems to work, despite having only a cheap plastic bucket for a cabinet. I'm more and more thinking it is BECAUSE it has a 5gal. bucket for a cabinet. A tubular structure that is closed at both ends is exceptionally rigid. It is both round and tapered, reducing potential standing waves inside (no sides are parallel except the top and bottom. And the volume is reasonably close to optimum for the driver. Being comparatively inexpensive helps, too. But it does have a drawback; it's absolutely hideous! So, how to remedy this? Why, build a nicer bucket, of course. Here's what I came up with - a nonagonal, truncated pyramid of very nearly the same volume. 9 sides and tapered, a reasonable approximation of a truncated cone.
I first determined the areas of the ends of a real bucket, and then drew nonagons having the same areas (Autocad and the internet were a big help); the difference in OUTSIDE dimensions of the two nine sided figures is the amount of taper to be cut into the staves, with the lengths being that of the real bucket. Two can be built in an afternoon for the cost of 3 - 8' lengths of 1x6, and some plywood scraps for the ends. Milling materials is rather straight forward because we don't have to cut matching bevels on both edges with this method, and the glue up is actually dead simple since the pieces are self aligning. Clamping is easily accomplished with a couple strap-type clamps.
Here's how it's done. First, rip the staves to the outside dimension of the bottom nonagon. Cut to length. Next install a dado blade in the saw and tilt the arbor to 40° and adjust the height so that it makes a cut 0.625 " deep. My saw tilts left, so the fence is installed to the left of the blade for the next cut. Adjust the fence so the inside edge of the dado just grazes to bottom corner of the stock and cut a rabbet along ONE edge only. RE-install your rip blade set blade angle back to vertical. The end of the staves will be shaped like this, with the outside face on the bottom of the picture:
Now we can cut the taper along the uncut edge and assemble. The pieces go together like this:
I first determined the areas of the ends of a real bucket, and then drew nonagons having the same areas (Autocad and the internet were a big help); the difference in OUTSIDE dimensions of the two nine sided figures is the amount of taper to be cut into the staves, with the lengths being that of the real bucket. Two can be built in an afternoon for the cost of 3 - 8' lengths of 1x6, and some plywood scraps for the ends. Milling materials is rather straight forward because we don't have to cut matching bevels on both edges with this method, and the glue up is actually dead simple since the pieces are self aligning. Clamping is easily accomplished with a couple strap-type clamps.
Here's how it's done. First, rip the staves to the outside dimension of the bottom nonagon. Cut to length. Next install a dado blade in the saw and tilt the arbor to 40° and adjust the height so that it makes a cut 0.625 " deep. My saw tilts left, so the fence is installed to the left of the blade for the next cut. Adjust the fence so the inside edge of the dado just grazes to bottom corner of the stock and cut a rabbet along ONE edge only. RE-install your rip blade set blade angle back to vertical. The end of the staves will be shaped like this, with the outside face on the bottom of the picture:
Now we can cut the taper along the uncut edge and assemble. The pieces go together like this:
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