Stave formula?

[Russell Neyman]

Does anyone know the formula for computing the compound angle for a stave? I'm planning an eight-faceted urn, and need to cut the individual pieces on my table saw

Malcolm Tidbits had a chart with his segmented bowl video set, but I'll be darned if I can locate it.

[Richard Madden]

I made some staved vessels a few years ago and I believe the angle you want is 22.5 degrees for the stave sides. The other angle is a matter of choice, probably somewhere around 4 degrees.

[John M. Smith]

Google compound miter angle calculator.

[jack forsberg]

http://www.woodturner.org/resources/Tibbetts%20Handout.pdf

[John C Lawson]

There is also an Android phone app, not free however at https://play.google.com/store/apps/details?id=com.woodturnersresourse.stavecalc

[Reed Gray]

Draw it out full scale, top and sides. Extend the lines out past the dimensions. Cut out the paper or poster board, and use that for your angle setting jig.

robo hippy

[Russell Neyman]

It has been decades since I messed with trigonometry so I guess I'll take Robo-Hippy's suggestion and draw it.

The project, by the way, is a lacewood urn. That species CAN be beautiful, but only from the flat grain. The side grain is simply UGLY, so if I glue staves I can keep the best sides outward. I plan to trim each stave with ebony. Will post the results.

[David Reed]

Here is a table I have used for quick reference when the numbers were suitable.271604

[John Lifer]

here is an online calculator
http://www.woodturnersresource.com/extras/projects/segmentcalc/index.html

[Patrick Moran]

What I've done in the past is take 360 deg. and divide by the number of staves, say its 8 that would be 45deg. and then divide that in half cause it takes 2 pcs to make the angle and you would have a cutting angle of 22.5 deg. If it was 9 staves it would work out to 20 deg. cutting angle.

[Russell Neyman]

Pat, that's if the staves are vertical; I'm making an urn-shaped hollow form, and (because of the peculiar characteristics of lacewood) need to orient the grain along the various contours. And because my stock is 2x8, I can't cut it on my chopsae like crown molding. This calls for the aforementioned compound miter.

Thanks to all of you who provided information.

[Thom Sturgill]

I have made two staved urns. One small and one sized for human cremains, which was given to my BILs family when he passed. In both cases I figured the vertical angle and made a tapering jig. I then set the blade at 22.5 degrees and cut each piece using the tapering jig. That produced tight joints. The smaller urn is about 2 1/2 years old and still tight, though I was taken to task for gluing in a solid base. Sinbce the base is only about 1 1/2", movement is totally negligible.