Here I’m again to show you the second part of my blog.
To start with this, you need a life size plan. First thing to do is drawing parallel horizontal lines represinting the thickness of the timber you intend to work with, each zone represents one level or (ring). Devide it in half with a vertical line to represent central line. SAY, your bowl is made of 4 level, each level 12 segments. Draw your bowl within 4 zones, number them 1 to 4, ( you may need to draw only half of it as I do in my drawing here). Next, draw 2 lines on each level to represent the width of level. Some tolarance spaces have to be added for any mistake.
Further down, draw 2 crossed lines meet at a point on central line, at 30 degrees. Now use the compasses to measure the outer radius of each level and draw a line to conect the crossed lines. that curve represents the length of segment when the bowl is turnd. The real length that you need is the stright line that conects radioses and tuches the circumference. So,the end of the story is A- life size plan, B- the brocken line is the width of the segment and the red line is its length. Hope it is clear enuogh to the job.
It is very difficult to cut the segment in level #4 with clean cut and make all segments meet at one point, as the saw will leave some damage to that 30 degree corner. The solution is to make a design advantage of this problem by drilling or cut a big hole in the centre and re-block it with a disc of the same timber or even different kind and coloure timber. AND then the problem is solved for a better look !!
-- Sam Shakouri / CREATING WONDERS WITH WOOD.....Sydney,Australia....