Unfortunately I had to say good bye to an old friend this week, my Black and Decker Quattro, we had been through a lot together, we had first met at university were “Blackie” had helped make many a design project, many evenings we would stay up together to the wee small hours drilling, cutting and sanding. Blackie’s heart (a 12 volt Nickel Cadmium battery) had been weak for some time now, on Monday whilst trying to cut 18mm ply, it gave up. Although not entirely dead, the days of hard labour for Blackie are over and shall spend the rest of his life relaxing in a cupboard for old tools, doing the occasional bit of work around the house.
On a more serious note, this week I have been progressing by addressing the problem of the lateral stiffness of the chairs. I have focused upon the outer chair as this is the least stiff. I made new side panels out of 18mm ply using the same profile as the originals. The result is a significant improvement upon the prototype whilst still maintaining the slender aesthetics. There is however still some improvement to be made as I’ve only tested it with myself and seeing I weigh about 75kg the stiffness needs to be improved for heavier people and for misuse. Further improvements could be made by reducing the force acting upon the side panels and increasing the side panel stiffness by increasing the leading leg thickness and possibly changing the radius of the legs. Hopefully I can tweak the design using some structural analysis software.
Thank you Lizzy for the Loan of your jigsaw.
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