I do wish you wouldn't weld galvanized metal inside & especially without an air mask. That yellow smoke coming from the weld can cause "galvanic poisoning" which can harm your nervous system.
A bit of an odd project. That frame looks seriously strong, but I can see that oil drums lifespan being measured in 10's of hours (Rather than 100's) before it's either too distorted and out of round to keep working, or the abrasive action of the sand or chippings sliding about inside wear it too thin to hold together anymore. It's a nice build, but I'd have thought something like an old, rusted beyond use, compressor tank would have made a significantly better starting point for the drum.
Going way too fast..a single 55 gallon barrel is really too small for all the trouble making your own. Those wheels will fail after a few yards of work, especially at those speeds.
