Hydraulic components are the industrial power transmission version of LEGO. Pumps, cylinders, valves – pretty much everything is standardized, and fitting out a working system is a matter of picking the right parts and just plumbing everything together. That’s fine if you want to build an excavator or a dump truck, but what if you want to scale things down?

Miniature hydraulic systems need miniature components, of which this homebrew hydraulic valve made by [TinC33] is a great example. (Video embedded below.) If you’re curious about why anyone would need these, check out the tiny hydraulic cylinders he built a while back, wherein you’ll learn that miniature RC snowplows are a thing. The video below starts with a brief but clear explanation about how hydraulic circuits work, as well as an explanation of the rotary dual-action proportional valve he designed. All the parts are machined by hand in the lathe from aluminum and brass stock. The machining operations are worth watching, but if you’re not into such things, skip to final assembly and testing at 13:44. The valve works well, providing very fine control of the cylinder and excellent load holding, and there’s not a leak to be seen. Impressive.

[TinC33] finishes the video with a tease of a design for multiple valves in a single body. That one looks like it might be an interesting machining challenge, and one we’d love to see.

Thanks to [mgsouth] for the tip.