Ringmaster Bowls -- Straight versus Curved Sides

(Click any pic for a larger image)

For the first few years after getting my Ringmaster, I only made straight-sided bowls, which is all you can really do when the rings are cut from one disk.

A couple of years ago, I joined a Facebook group called 'Ringmaster Lathe' (Ringmaster Lathe Group).  A member there has developed a technique of making curved Ringmaster bowls using two blanks instead of one, which he generously shared with the group.

The blanks can be segmented, and glued up using two or more hardwood species, resulting in various patterns in the finished bowl.

For my first attempt, I made one thick blank -- 1.5" thick -- and ripped it into two blanks at the band saw.  These blanks are segmented yellow cedar, red cedar burl, and a sandwich layer of 3/16" mahogany.  They were then cut into rings on the ringmaster.

As you cut the rings, you alternate from one blank to the other, slightly increasing the angle of cut for each ring.  So when they're glued together, there is a 'progressive' curvature. 

 

Now would NOT be a good time to switch on the lathe! 😁 

It is glued up at the lathe so the quill keeps the bottom centered, and each ring is positioned in 'Cole jaws' to ensure they are centered, too.  The tailstock also provides some clamping pressure.

It makes for a slow glue-up process with an hour or two between each new ring being added.  But it's worth it when the bowl turns true with minimal wobble, mounted on the lathe.

A freshly glued-up bowl is rough and requires considerably more shaping and 'cleaning up' at the lathe, than a straight-sided bowl.  A razor-sharp bowl gouge or curved scraper seems to do the trick.  Then sanding at the lathe, from 60 or 80 grit, right up to 600+. 

Bill's technique uses twice the wood and it's twice the work, producing two blanks instead of one, but I think it's worth it.

And here's the finished bowl (note the curved sides versus the straight sides of the bowl at the top of this post).