Turning a Table Pedestal

wrote: (clip) I've tried with no luck to create a cylinder with 2x4s but I can never get

^^^^^^^^^^^^^^^^^^^^ This is a problem that segmented turners deal with all the time. One of our club demonstrators did it by trial and error, making tiny changes in the angle until things fit together nicely (using short scrap pieces, of course.)

Or, you could turn all but one of the pieces alike, and take out the cumulative error by playing with the angle on the last piece (again, using a piece of scrap.)

Or, you could glue up a bundle of 2x4's, flat-to-flat, and then turn the pedestal as though it were one piece of wood, Turn on an axis so the grain layers are symetrical, and it should look pretty good (though not as elegant as pie segment glue-up.

Draw a circle the dia. of the pedestal with a compus than devide into pie shaped peices ,start with four segments than eight than sixteen. Than devide 360 by 16 and use that number as angle to set your saw. If you click on my web page you can see bowls I made with segments. Jerry

"Jerry - OHIO" (clip)Than devide 360 by 16 and use that number as angle to set your saw. (clip) ^^^^^^^^^^^^^^^^^^^^^^^ In principle, yes. 360 divided by 16 = 22.5 degrees. If your saw setting is off by half a degree, the cumulative error is 8 degrees. I think that is where Ironspike is having trouble--how to set the saw so the pieces fit together with no visible error.

For a segmented bowl I can see why you would want 16 segments, or even more. But, the more segments, the more the error multiplies. And I can't see the need for 16 segments for a pedestal. 8 ought to be plenty, or even 6. With

While the other posters are absolutely correct about calculating angles and dividing 360 degrees, I have a hunch that I know where you are getting into trouble.

As much as the wrong angle will give you gaps, so will starting with stock that is not straight/flat and square. If you start with a catty-whompas (spelling?) 2x4, your bevel cuts for wedges will never be straight and you will have gaps.

Face joint, then edge joint your stock before cutting those bevels. (find someone with a jointer). 2x4's are notoriously unstraight/flat.

Yes, it's a flatwood solution to a turning problem.

-Steve

By all means start with flat, straight stock. Then cut the miter angles as close as you can get them. Glue them up in two subassemblies, each corresponding to half of the column. When you bring these together you will see the error, but it will be quite easy to plane it out on the four surfaces, making the mating surfaces on each half be planar.

There are some tricks for gluing up the two halves. One is to use hot hide glue and make rubbed joints. Good rubbed joints are surprisingly durable. Another is to glue up the segments using band clamps, but with dowels stuck in between two opposite joints. The dowels will distribute the pressure evenly over the joints that are being glued. After the glue dries, take away the dowels and plane the exposed surfaces.

- Neil

The 16 segments was just an example. Jerry

I've used a similar technique with segmented bowls. Glue the half rings together and then true too halves for a perfect match. You need to leave yourself enough material in order to turn your cylinder when finished, so make sure to make your rough piece some larger.

JD (Kentucky)