As for a large stone wheel, there are old pictures of grinding wheels that are foot powered. I was thinking more of the pto attachment on a tractor for a wheel that size. I would think a huge stone wheel like that would have a lot of momentum and not require a lot of power to start it spinning.
A saw is faster for removing large amounts of material but a grinding wheel will give you more control You can cut curves with a wheel while youre restricted to straight lines with a saw You must be careful when grinding delicate material A coarse wheel thats ideal for jasper would shatter an opal It can also open up dozens of
Even larger wheels, wider wheels, or more specialized wheel compositions jump up into the $500+ range pretty quick. And the links above are just the first place I found that had a decent on line selection of wheels. Don39;t know how their prices compare if you shop around. Google Search: quot;Large Grinding Wheelquot;.
Next, make and attach the lower drive assembly to the treadle. As shown in Pictures 2 and 3, this is a simple assembly with a tapping hex bolt holding 2 washers and an eye bolt for a drive. Don39;t drill the pilot hole too large. Use a wrench to tighten this assembly into a block of scrap 2x4.
I have been looking offhand for a while for a large grinding stone. Maybe 3 to 4 wide by about 18 to 36 in diameter. Slow speed stone, 300 RPM or slower, to be used in a wet trough. I know sandstone wheels are pretty common to find in antique stores or the like but dose anyone still cut them out ...