Yikes, talk about a long "on hold" period. After a nice projects-filled weekend I finally managed to make some headway on my Box Charkha project; specifically the drive wheels.

To catch up- I've been using this excellent article (now available in PDF) from Interweave's 1996 Spin-Off on building a cigar-box charkha with some modifications. After amassing all the supplies and working on a plan I realized I didn't have access to a drill press need to drill perfectly centered and balanced holes for the wheels. I was rather amused at the suggestions that everyone "knows someone with woodworking tools". We're 20 something techies, everyone I know is more likely to fix your computer or network than build you a cabinet.

Thinking it was too bad I didn't live near my parents anymore I finally realized I could just ship the marked up pieces to my Dad to drill for me (thanks Dad!). I got the pieces back and it was promptly put on the back burner again by other projects. So, (somewhat) fast-forwarding to now here's what I did.

The large drive wheel is made of the suggested two "basswood plaques" that are glued together right sides facing. The other larger wheel is a sandwich of three wooden circles with the smallest in the middle to create a grove that holds the drive band. A wooden spool is the smaller underneath wheel.

For the support rods and bearings I deviated from the article. I sawed plastic sewing machine bobbins in half to use as bearings instead metal tubing- easier to cut. Also easier to cut than the suggested metal support rods were bamboo knitting needles. This worked well since knitting needles come in such a variety of sizes, obviously. The bamboo needles were chosen to fit the inner diameter of the bobbins and the wheels drilled to the bobbin's outer diameter. The mounting blocks should be drilled to the exact needle size and the rods tapped in tight. My measuring was off however and my holes were a bit large so I improvised with wrapping an o-ring around one and using another bobbin half as a spacer for the other (and wood glue, lots of glue).

Under the large wheel, not shown, is a "washer" made from cutting out a circle from an empty plastic food container. For the drive band I used jewelry beading hollow tubing (not sure what this is called) since it was easy to cut to size. In the photo above you can see the double wheel is flipped over to show the spool/smallest wheel. I think I'm going to replace that one however with a smaller one, especially after referring to my own calculations (duh) as it'd put me closer to my desired ratio. The other reason I discovered while taking these photos- the box no longer shuts, oops.

I originally sawed one of the spools in half, as it was a bit taller than it needed to be but my hand sawing leaves much to be desired. Even after lots of sanding it was far from level. Well the double wheel assembly comes off the post for storing and I laid it in the box to make sure it'd still fit with the full-size bobbin. It did; so I thought, great I'll just use that. Forgot to take into account the support rod which also includes the height of the mounting block, heh. That's kind of how this project has been going, trial and error. But I'm enjoying the creative challenge-next up, the spindle assembly!