Atvērta segmenta bļoda

Open Segment Bowl

The inspiration for this bowl came from the gallery style bowl, where spindles are used to bridge the gap. By using three rows of open segments instead of spindles the appearance of the bowl can be changed dramatically.

The gluing together of the bowl blank is made easy by the open segment jig I designed especially for this type of project. (Available through my website www.sueharker.com).

To make this bowl you will need a bowl blank approximately 10 (250mm) diameter x 1 (32mm) thick and for the segments, strips of thicknessed timber approximately 1 (32mm) diameter x 5/16 (8mm) thick.

Both faces of the bowl blank need to be totally flat, for the segments to glue to; this can be achieved by passing the bowl blank through a planer thicknesser. Drill a recess the correct size for your chuck and mount the bowl blank on your lathe.

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.

Fig 1

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.

Fig 2

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.

Fig 3

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.

Fig 4

Set the Mitre Fence to 10

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.

Fig 5

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.

Fig 6

Place the First Row of Segments in the Jig

Smooth any torn grain using a sanding block and place the row one segments in the jig.

Fig 7

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.

Fig 8

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.

Fig 9

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.

Fig 10

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.

Fig 11

Shape the Outside of the Bowl

True up the bowl blank and form an ogee shape. Form the foot and reshape the recess for re-mounting. Sand to a finish before removing from the lathe.

Fig 12

Turning the Inside Rim

Re-mount the bowl and turn the rim to the required thickness.

Fig 13

Cutting the Segments

Gently remove the edges of the segments and continue to shape the inside profile of the bowl.

Fig 14

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.

Fig 15

Remove Evidence of Chucking

Mount the finished bowl in a set of Cole or jumbo jaws and remove the evidence of chucking.

Fig 16

The Finished Bowl

Here we have the finished bowl with three rows of open segments used as an accent.