Ask HN: Website for industrial automation parts for DIY projects?

Can anyone here recommend a website where one can buy "industrial" type gadgets for custom building "machines"?

Specifically what I am in need of right now is a low cost solution for automatically proportioning (by weight) pet treats. They are an odd shape and a bit sticky so our existing machine can't seem to cope with them, and apparently a proper machine which can handle it is ~ $100k.

So in the meantime I thought perhaps a person could take some off the shelf parts and build something from scratch.

The second question is, can anyone comment on how these things are programmed? Would it by typical to have an API accessible from a windows machine to control them?