# Segmented Fail (?) -- 20% rant, 80% cry for help

 Blog entry by dspahn posted 11-26-2011 09:22 AM 1975 reads 0 times favorited 14 comments

So after watching some videos on segmented bowl construction and turning, I decided to give it a shot while I wait for my cole jaws to arrive in the mail. I actually went to a lumber place and bought a few pieces: some walnut, alder, cherry, and something with the word “african” in it… maybe mahogany, but I’m not 100% sure.

And then, after I got home, whinging internally about spending \$40 on an amount of wood you could maybe build a desk for a barbie doll out of, I realized that I didn’t have any good way of cutting strips of wood with 22.5 degree angles.

Now, I like math. I always have. I understand that 22.5 degrees is half of 45, which is half of 90, which is a quarter of 360, and why 8 pieces need 22.5 degree cuts in them. I could give you the measurements in radians if you’d like. But tonight I learned the hard difference between theory and practice. More on that later.

So to rectify my lack, I decided to create an angle jig for my table saw. First I created a sled. Pictures below:

And here’s the underside of the sled and what it rides on:

Then I used a piece of MDF (I think), and some small pieces of dowel to hold it in place at 0, 22.5, and 45 degrees as needed. The nice thing about this method is that while it’s not infinitely adjustable, to add a new angle, all I need to do is drill a new hole. You can see the jig in the first picture above.

I used these tools to find my 22.5 and 45 degree angles:

The 0 degree angle was found by placing a framing square against the blade of the table saw, and then drawing a line.

The tools in the picture are: a couple of framing squares, a protractor doohickey, and what I think is called a compound square. To drill the holes for the dowels, I used my shopsmith in drill press mode.

In retrospect, rather than create the sled and try to find the angles, I might should have used my radial arm saw, but the table on that needs to be completely replaced, and it’s harder to get at than my table saw. You see, I’m trying to do a woodshop in a one car garage that also holds my motorcycle, several shelving units, a good sized tool cabinet and a bandsaw.

So, rather than dive right into cutting up my expensive wood, I decided to give the new jig a test run on some scrap wood I had left over from something else. The cutting went swimmingly. Here’s what I ended up with:

Which all looked well and good until I actually tried to assemble them into an octagon. And here’s where the frustration set in:

If I put 7 pieces flush together, the 8th piece just doesn’t fit very well. Which means my 22.5 degree angle was something other than 22.5 degrees. And here’s the gaps if I place the pieces together not quite flush, but very close:

And now for the questions. Am I close enough? And by that I mean, if I decide to chop up my “nice” wood, and glue those segments together, will I end up with a nice looking ring, and thereby a nice looking bowl? Or do I need to get closer to 22.5 before ruining the “nice” wood? And if I need to get closer to 22.5, how do I do it? I have a table saw, a radial arm saw, a band saw, a shopsmith, and a router. And as far as angle type tools, I have several framing squares, two compound squares, that protractor doohickey, and that’s about it. Can I even do what I’m trying to do with the equipment at hand? Or do I need to obtain something else? And if so, what do I need?

On the bright side, even though I’m not ecstatic about my results, I still had fun killing a few hours in the garage.

Thanks for reading, and thanks in advance for any tips or advice you might have to offer.