Preparing the Bowl Blank
Turn into the round and chamfer the outer edge. Apply masking tape to the reverse of the blank; this should hold the two pieces together sufficiently for parting through. Mark for grain alignment and part off using a 6mm (1/4”) parting tool starting approximately 63mm (2 ½”) from the centre at an angle of approximately 45º pointing towards the outside edge.
Measuring the First Row
Position the bowl base, face down, on an 18 segment jig, using the concentric circles to centralise. Measure between two of the ‘spokes’ slightly larger than the diameter of the bowl base. This measurement is the width of each segment required for row one.
Measuring the Second and Third Rows
Place the bowl top, the correct way up, on the jig and measure the width between two of the ‘spokes’ slightly smaller than the diameter of the top. This is the width of segment required for row three. The size of segment required for the second row is calculated using rows one and three measurements. For example; if the first row measures 20mm and the third row measures 30mm, the second row will be cut at 25mm wide.
Place and Clamp the Spacer Block in Position
Using a table saw, place a sacrificial piece of timber (a spacer block) alongside the rip fence. Measure the required segment width, from the spacer block to the blade. Secure the rip fence at this position and clamp the spacer block in place.
Set the Mitre Fence to 10º
Set the angle mitre to 10º (the required angle for the 18 segment wheel). Position the segment strip along the mitre with the edge to be cut touching the spacer block.
Carefully Cut the Segments
Hold securely against the mitre and push the timber through the blade. Using a push stick, move the cut segment away from the blade. Flip over the timber strip and repeat the process, until the required number of segments have been cut.
Place the First Row of Segments in the Jig
Glue the First Row of Segments in Place
Apply glue and position the base on the segments ensuring it is centralised. Place under a clamp with overhead pressure and remove any excess glue.
Glue the Second and Third Rows of Segments in Place
Position the second row of segments in the wheel and apply glue leaving a channel down the centre of each segment glue free. Hold the base, with the first row of segments attached, over the segment wheel and rotate half a segment width clockwise. Secure in a clamp and remove any excess glue. When the glue on row two has dried, glue the third row of segments the same way.
Clamp the Bowl
Place the bowl top upside down on the jig, ensuring it is centrally located. Apply glue to the segments and using the grain alignment reference marks made earlier, place the bowl base on the bowl top. Secure in a clamp and remove excess glue.
Mount the Blank to the Chuck
When the glue has cured, usually after 24 hours, mount the finished blank on the lathe using the recess cut on the inside of the bowl.
Shape the Outside of the Bowl
Turning the Inside Rim
Re-mount the bowl and turn the rim to the required thickness.
Cutting the Segments
Gently remove the edges of the segments and continue to shape the inside profile of the bowl.
Apply the Oil
When the required shape is achieved sand through the grits to a suitable finish. Clean out the dust between the segments and apply oil making sure the segment end grain is coated.
Remove Evidence of Chucking
Mount the finished bowl in a set of Cole or jumbo jaws and remove the evidence of chucking.
The Finished Bowl
Here we have the finished bowl with three rows of open segments used as an accent.
The open segment jig I designed especially for this type of project is available through my website www.sueharker.com.