You are taking it literaly. Actually if you see the Bob design, you will realise it is almost like a foot-driven rusty/krusty style hammer without the power-assistance.
With minimum mods, it can be converted.
@Rob N
If you want to spend less money, but also want to continue with your work, then you have to check out more things. Pls first get the feel of a treadle yourself, which is already suggested. Also see other real people at work, and from that assess your needs. If you must go for a treadle hammer, then I suggest the classic swinging-arm design. It will be very useful in lots of work, and also will be cheaper to build. Later you can go for a power hammer.
Good luck in your journey.