Jeremy,
It is all brass from the rack at the local farm store. I can get you some measurements if you want. The bottom is made from a pretty thick piece that was full width (1.5" I think) and I basically found a patent drawing of a bucket that I printed to a size that looked about right for the scale of the machine.
Let me see if I can find the link that I used. One of the photos in the build has the print under the bucket in one shot.
The video at 1:50 shows the drawing I used. I basically used the drawing to match the curve of the bottom piece. Still looking for the link, stand by...
Okay, let's see if this link works...
http://patentimages.storage.googleap...1/imgf0004.png
And this should be the full document...
http://www.google.com/patents/EP0321542B1?cl=en
And mine measures .070" center base plate 2" wide at the mouth and I tapered it a bit toward the rear to make it load a bit better. The sides are about 1" tall and I made them from thinner .035" but they could have also been .070" to add weight to the bucket. I thought about adding wear bars to the under side of the bottom and maybe sides to give it more mass.
Jim