For about $80 I got 20' of 2x2" 3/16" mild steel square tubing. I made some of the cuts with a metal cutting blade in a mitre saw. However, this took about 45 minutes for each cut. It was precise, but impractical. I guess it takes a much bigger cutoff saw to do this, since at the metal supply store, their big saw cut it in seconds.
I gave up on that approach and made the remaining cuts with a hacksaw blade in a sawzall. It takes less than 5 minutes for each cut, although it's somewhat less precise.
I then ground the edges of all the parts that will be welded. The bevel allows the welding arc and flux core wire to penetrate and make a better weld.
I'm fortunate to have a friend with a powerful wire feed, gas-shielded welder. I've never welded before so my welds are very ugly. But at least it's easy to make an ugly weld.
I added hinge for the part of the forks that will clamp onto a lip at the top of the bucket, to hold the forks in place. Since the zinc on coated hinges is poisonous if vaporized, I first ground the coating off the hinges with my grinder, while outside, and while wearing a dust mask. I welded some 1/8" plate on the ends of the forks, and under where the hinge is welded, in order to seal the tubing.
I spent quite a bit of time grinding my ugly welds flat. Add some paint though and it starts looking good. I used Valspar "AC Orange, Tractor and Implement" spray paint. It looks like an exact match for Kubota Orange. I cleaned the metal with paint thinner and a rag. I put on two coats of rust-inhibiting primer, then several coats of orange.
I positioned one fork to the bucket to mark where the hinged section meets the top lip of the bucket. Then I ground a groove into the fork to contain the lip. I rounded the edge of the cut, and also the corner of the part so that it fits flush under curved the bucket lip. I could then clamp the fork in place and drill a hole for a bolt that will secure the hinged part tight to the bucket lip.
The final forks are very useful, although strictly light duty. I didn't yet add a plate that hooks under the lip of the bucket, as specified in the design. I'm hoping that will help a bit with the current side-to-side instability of the forks.
