Figure # 7 shows you the length of each segment of inner and outer layers
FIGURE #6 shows the width of each level or ring (toleration room has to be left)
Gage #4 to gage outside of the outer layer (or the bowl)
Gage #3 to gage inside of the inner layer (or the bowl)
Gage #2 to gage inside of the outer layer
Gage #1 to gage outside of the inner layer
The plan with gluing line has to be in life size
The simple idea to build a double layered bowl is turning two bowls for the purpouse of put them inside each other and turn them together as one bowl. If you were a segmented turner, you would know how to build segmented bowl. If not, use two different coloures solid blanks and save yourself from extra troubles as I did with the first one.
You have to have a cross cut life size plan. Draw a gluing line between the inside and outside surfaces.
Coppy your plan four times. Glue each coppy on thin plywood. Cut two gages for each layer, one to gage outside and one to gage inside of each layer, (4 gages). So, you will have 4 surfaces to turn. I started with outside of inner layer using gage #1, repeatedly until it sat on inner layer passing the centre point.
The second surface was inside of the outer layer using gage #2 and I did the same, repeatedly tested the gage until it sat presicely touching the inner surface of the outer layer.
NOW the two layers are ready to kiss:)) each other and become one blank.
While you turn the bowll, repeatedly use gages #3 and 4 to avoid crossing gluing line. REMEMBER: There is no room for any mistake.
HOWEVER, if you chose to add dots or plugs, you should add them before the final touches of turning, so they would take the same shape of the body they would be inserted in. (No need for sanding the first two srfaces)
AND, if you chose to go for segmented turning, you should study figures #6 & 7. (5×12 segment ring)
I wish everyone who would like to do it, a very good luck, and more importuntely, enjoyable time.
-- Sam Shakouri / CREATING WONDERS WITH WOOD.....Sydney,Australia....