Multi-Center Bowl – Dave Dernie

Club Meeting :  27 July 2015
Report by: Dave Armstrong

David started his demonstration by discussing the “Methodology” or the process of turning his pieces and showed us examples or his two types.  One being an oblong piece with three dishes and the more traditional round piece, also with three dishes.  David mentioned that it is possible to make pieces with more dishes (bowls) depending on the swing of the lathe and your layout.  Dishes could also overlap.  He showed us the process of designing and making suitable jigs and faceplates with additional sacrificial fixing plates.
David stressed the safety and balancing required, and the need for accuracy when marking out. Other considerations are aesthetics and the use of contrasting timbers along with the relation between lathe speed, diameter and chisel speed.
Throughout his preamble and demonstration he supported his comments with a very well-constructed PowerPoint presentation.

Demo – Oblong Piece

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David positioned his oblong stock on the oblong jig attached to the large faceplate which was swung at 45deg over the bed and turned the first outer dish.  He then made a template of the depth required to use as his guide for turning the other dishes.  Next he tipped his piece end for end and turned the second outer dish. Having completed these he then goes on to turn the centre dish and finished to suit.
He stressed the safety aspects concerning projecting wood spinning on the faceplate, keeping elbow into the body and also the need to ensure you mark out accurately or the dishes may not be positioned correctly.

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Round Piece

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David mounted his round work-piece to the large faceplate and proceeded to show the marking out using indexing and his drilling jig which was fitted to the banjo.  This ensures the dishes will be uniformly positioned around the blank. Each position was numbered.
The piece was then positioned at number one marking.  The complete faceplate and workpiece are checked for balance and the first dish turned and sanded.  Then he repositioned the work-piece to the next positions, balancing and turning until finished and sanded.

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As usual, considerable time is spent making jigs, sacrificial faceplates, and marking out etc. but the reward is a repeatable piece in the end.
Davids demo was so informative that everyone remained absorbed throughout and he fielded many questions at the end. Thanks David for your great demo.


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