Finishing Bikes and Trees 2

With the turning complete, I had to figure out how to get a clean, straight slice through the work on the bandsaw. First, I made a sacrificial V-sled the hard way by grabbing a nasty old cedar table leg out of the burn pile, jointing and squaring it, and then taking angled cuts out on the tablesaw. Completed, it cradled the turning securely and let me use the mitre gauge to set the cut angle.

I also took the time to carefully reset the blade tension and guides so that the blade stayed quite straight and did not wander. I was rewarded with a very clean cut. I can't see any blade tracks in the photo, and it sanded dead flat in just a few strokes. (To keep flats while sanding, I lay a full sheet of sandpaper on a flat table, lay the flat of the work on it, figure out how to hold the work to avoid any rocking, and then take straight light strokes back and forth. It usually works out very well.)

A quick test fit kept me excited about the project. I like this:

But the sphere was now clearly oval, as the kerf of the cut was much thinner than the sprocket. I measured the difference with calipers and marked the excess with a round marking gauge.

Doesn't that look precise and sophisticated? I think the Fine Woodworking magazine next step would be to construct a shooting jig for a low-angle bench plane and take sweet shavings of end grain off until the marked line was just kissed. But I'm not that good.

Instead, I clamped a belt sander upside down on the bench and did my best to sand down to the line more or less flat. More less, in fact, which led to a lot more hand-sanding to restore the flat. (So maybe the shooting jig is the right thing, really.) But it got there.

I carefully put the sprocket right where I wanted it, and then traced the inside onto the wood. I had started out with the idea of a loose tenon, and then dowels, but drilling into the top was looking like trouble. I decided to use brads as pins, which let me progressively refine the orientation of the gear by adding brads.

Once the sprocket was locked in place, I snipped the heads off the brads and carefully positioned the top. Once I was certain it was where it needed to be, I pressed down to mark the pin locations, and then drilled at the marks. With a tiny drill bit, I could just hold the top to prevent it tipping on its round.

The press fit was very firm, and so I completed the assembly without glue after finally hand-sanding the turning with the grain. With a rubbed coat of walnut oil, it turned out very nearly as I had hoped:

I don't think that this will be the last of this sort of thing, as my head is exploding with variations on this theme. It's fun to be inspired!