| If you have ever looked at a barrel to see how it | | | | (360/5=72. 180-72=108. 108/2= 54) The angle at |
| is assembled, you will have noticed that it is | | | | each end of the segment is 54 degrees, which is |
| constructed of segments. These are called | | | | the miter angle at which you will cut each |
| “staves”, and the principle is used in any | | | | segment. |
| application where the end product is to be | | | | When building columns, whether turned or |
| rounded or connected end to end in a circular | | | | facetted, I like to join the staves together with |
| fashion. | | | | splines, and I use 1/8” plywood, or door skins, |
| Columns, lamp bodies, bowls and turned boxes | | | | for the splines. The carbide saw blades that I use |
| are all examples of stave construction that this | | | | cut a kerf just the right size for the plywood, and |
| article will cover. | | | | the splines add tremendous strength to the joint |
| When staves are put together in this way, a | | | | through additional gluing surfaces area, and they |
| polygon is formed, with each facet or side of the | | | | keep the staves in perfect alignment in the gluing |
| polygon being a stave. Laying out polygons is not | | | | and clamping process. If you are a biscuit joinery |
| the mystery a lot of people believe it to be. | | | | devotee, by all means use biscuits. They serve |
| Squares and triangles are easy, but when you get | | | | the same purpose, and they have the added |
| into pentagons, hexagons, octagons etc., things | | | | advantage that the groove doesn’t show at |
| get a little trickier, but a little geometry will rescue | | | | the end of the stave. In either case, make sure |
| your project. | | | | that they are deep enough not to interfere with |
| In any polygon except a triangle, the included | | | | turning, if you intend to turn your project on a |
| angles add up to 360 degrees. Once you decide | | | | lathe. |
| on how many sides or segments your polygon will | | | | Segments or staves can be of contrasting woods |
| have, simply divide 360 degrees by the number | | | | for added interest, and can be glued up in a |
| of segments. Each segment and it's radial lines | | | | myriad of designs like checkerboards, book |
| form a triangle whose included angles equal 180 | | | | matched grain patterns, or maybe a strip |
| degrees. | | | | between staves. If using a strip between staves, |
| Divide 360 degrees by the number of segments | | | | you needn’t cut a miter angle on the strip, |
| desired, to find the included angle of the radial | | | | because the strip will be parallel to the miter cuts |
| lines. Subtract this number from 180 degrees. | | | | on the stave. You do, however, have to shorten |
| Divide the result by two to find the miter angle to | | | | the width of the stave by the width of the strip |
| be cut on each end of a segment, or each side of | | | | to maintain the desired overall size. |
| a stave. This holds true for any number of | | | | To form a base for a bowl, it is customary to cut |
| segments. | | | | wedge shaped segments, which, when glued |
| Let us assume a pentagon, which, of course, has | | | | together may be turned or bandsawed to form a |
| 5 sides. Divide 360 by 5, and you get 72 degrees. | | | | circle that will fit a recess cut into one end of the |
| This is the included angle of the radial lines, and | | | | glue-up. These segments may be the same angle |
| since a triangle has 180 degrees, the angles at | | | | as the staves, or any angle that is esthetically |
| each end of the segment are half of the | | | | pleasing to you, the designer. |
| difference between 180 degrees and 72 degrees. | | | | |