Tumble Rings again.

[joe greiner]

This set is made from white pine, from Home Depot, because my spruce supplier is closed on weekends.

The rings are 4 1/2" OD, 5/8" thick, to fit a pvc pipe coupling I used as a compression chuck for turning the inside. The overall chain is about 34" long, with 18 rings. Finished with satin finish polyurethane varnish, before assembly. Half of the rings are broken in cross-grain bending, stitched into the others, and glued with Titebond 2.

I also made a test with the same size rings, but in segmented cedar (2 layers of 12 segments each). The segments reached almost to the center of the ring for attachment to a faceplate, for turning the outside of the ring. Instead of breaking for assembly, I masked two locations of the pre-rings (i.e. without glue). I placed a drop of CA at those locations for temporary brittle assembly for turning, and glued them after final assembly. The finish here is EEE and paste wax, in three turning stages: outside, inside one face, and inside the other face.

Cheers,
Joe

[artme]

Smart work there Joe!!

Must try some rings one day.

[Ozkaban]

Nice! I reckon turning them round (across the cross section) would be a pretty huge challenge.

Cheers,
Dave

[Ad de Crom]

Joe, clever made, I think a lot of patience is needed to make this.
Very pretty.
Ad

[joe greiner]

Nice! I reckon turning them round (across the cross section) would be a pretty huge challenge.

Cheers,
Dave

It was indeed, especially at only 5/8" (~16mm) diameter. I used cardboard templates for both the outside and inside, turned to within 1mm, and sanded to 600. The insides were rarely concentric on both faces, and often met the outsides imperfectly. But they feel OK in operation. Luckily , they don't have to be exactly identical to one another.

I think there are two correct ways to assemble them (mirror images). I had a chat with one of my neighbors, a retired maths professor. Subject to correction, there seem to be [ 2^(n-1) -1 ] ways to assemble them wrong (n = number of rings). While rummaging in some old files, I found a chart I'd made around 1982 (for steel rings), and practiced with loops of electrical wire to verify it.

Cheers,
Joe