The Jig and Crank Parts
I built the parts to the crank shaft and then drilled some holes in that long aluminum plate to hold the parts in place. I thought that the holes in the crank parts would hold the rest of the parts in place, but I was way wrong! They jiggled around enough that the finished crank is not at all straight.
If it’s not obvious, there are two cranks and one is much shorter than the other. This is not how a typical engine crank would work.
I’m going to build another one and use two jig pieces, one at each end. They will be screwed together to keep them aligned to each other. It’s a lot of work but it will make a better part in the end. The alternative would be to just use the crank I have and bend it a bit to get the shafts aligned better. I’d rather make this particular part as clean and accurate as possible since it will be a centerpiece of the mechanism.