PC Bowl Design

Kevin's Woodturnings

DESIGNING A BASIC SEGMENTED BOWL USING THE SEGMENTED RING MAKER APP
ON A SMARTPHONE OR COMPUTER

This webpage is similar to my "Designing a Basic Segmented Bowl" webpage except that this one uses my Segmented Ring Maker App. This alternate method of bowl design uses no math and very little sketching and drawing. The computer performs all the calculations necessary to turn a bowl sketch into segmented rings. This webpage is intended for the beginning segmented bowl maker. I have made one design sheet to help the beginner through the design phase. Using this design sheet and my computer program, I have designed a 9-layered bowl using 12-sided frame-mitered rings. This webpage will walk you through the design steps.

To go to the webpage showing the bowl being constructed, click here. To go to the webpage that has plans for a frame-miter table saw sled that makes perfect ring segments, click here.

If you make a similar bowl and follow these steps, your bowl will turn out fine. Don't worry about the details of segmented bowl construction. Instead, spend your time thinking of an original design that you like. I'm sure that experienced segmented bowlmakers don't make bowls using all the steps on this webpage. I don't make segmented bowls this way either, but I think it's a good learning approach. Experience will tell you how to modify the steps. Until you are experienced, you shouldn't modify the steps until you understand how the changes will affect the segmented bowl construction.

Click on any photo to enlarge it.

	Figure 1 This blank design sheet is used for drawing the outline of your bowl. This sheet is big enough to design a bowl 12" diameter by 12 ring levels tall. Each row, 1 through 12, corresponds with a ring level of your bowl design. The grids on the sheet are intended to be 1" wide by 3/4" tall to make it easy to measure bowl ring dimensions directly from the sheet. But, I found that every printer seems to print the grids at different sizes. So, I suggest printing out one sheet then using a photocopy machine to enlarge the sheet to full 1" grid width.
	Design Step #1 Draw the right-hand half outline of the new bowl on the Figure 1 sheet. This is the first step in the design process. If you want to see what the whole outline looks like, hold the left side of the sheet against a mirror so you can see the reflection of the sheet. The entire outline can then be viewed. This design has 9 rings. The bottom ring will be a solid disk. The other 8 rings will be segmented. I have decided to make the top, middle, and bottom rings from purpleheart and the rest of the rings from maple. The bowl will be made from 3/4" thick kiln-dried lumber, purchased from a local lumberyard.
	Design Step #2 Draw the inner surface outline of the new bowl on the Figure 1 sheet using 1/2" wall thickness. The 1/2" wall thickness does not mean I'm going to turn the bowl to 1/2" thickness. The 1/2" is just a reasonably safe design thickness. You can turn your bowl thinner. On the other hand, if you don't make your segmented rings very accurately and they end up egg-shaped or the wrong diameter, then 1/2" might not be big enough. We'll take our chances on this one because I'm using a really accurate mitering sled (the one I designed on another webpage click here).
	Design Step #3 I have drawn the inner and outer ring radius lines for each ring on the Figure 1 sheet. The Segmented Ring Maker App uses the inner and outer ring diameters and the number of segments per ring.
	Design Step #4 On the Figure 1 sheet, measure and record all the inner and outer ring diameter dimensions for use with the Segmented Ring Maker App.
	Design Step #5 - Ring #2 Fill in the "Ring Design" screen of the Segmented Ring Maker App for Ring #2 segmented ring, like on the screen print at left: Ring Number = 2, Miter Type = Frame, Number of Sides = 12, Outer Diameter = 5-1/4, Inner Diameter = 1-1/2, Blade Thickness = .125 or 1/8, Filler Piece Width = 0. The greyed out (uneditable) boxes are not used for Frame Miters. The greyed out boxes are used for other types of miters, but not Frame Miters. Click the Calculate button on the "Ring Design" screen and the "Calculations" screen will appear, like the screen print at left. The "Calculations" screen will have all the calculated dimensions necessary for cutting the Ring #2 segments. Print the "Calculations" screen.
	Design Step #5 - Ring #3 Fill in the "Ring Design" screen of the Segmented Ring Maker App for Ring #3 segmented ring and click the Calculate button. Print the "Calculations" screen.
	Design Step #5 - Ring #4 Fill in the "Ring Design" screen of the Segmented Ring Maker App for Ring #4 segmented ring and click the Calculate button. Print the "Calculations" screen.
	Design Step #5 - Ring #5 Fill in the "Ring Design" screen of the Segmented Ring Maker App for Ring #5 segmented ring and click the Calculate button. Print the "Calculations" screen
	Design Step #5 - Ring #6 Fill in the "Ring Design" screen of the Segmented Ring Maker App for Ring #6 segmented ring and click the Calculate button. Print the "Calculations" screen
	Design Step #5 - Ring #7 Fill in the "Ring Design" screen of the Segmented Ring Maker App for Ring #7 segmented ring and click the Calculate button. Print the "Calculations" screen
	Design Step #5 - Ring #8 Fill in the "Ring Design" screen of the Segmented Ring Maker App for Ring #8 segmented ring and click the Calculate button. Print the "Calculations" screen
	Design Step #5 - Ring #9 Fill in the "Ring Design" screen of the Segmented Ring Maker App for Ring #9 segmented ring and click the Calculate button. Print the "Calculations" screen Now, all dimensions necessary to cut the segments for all the rings for this bowl have been calculated. I'll use these dimensions to cut boards to length and width, and then cut segments from the boards. It looks like I need about 40" of 1"x6" kiln dried maple and about 14" of 1"x4" purpleheart to make this bowl.
	The next thing to do is to start cutting segments and constructing the bowl. You can get started by viewing my "Basic Frame-Miter Segmented Bowl Construction" webpage (click here).