I recently got an inquiry from a prospective client who in his new-found retirement is going to make an Italian glass tile mosaic coffee table for their home. He's not a woodworker so was looking for a resource to make the base. The mosaic will be 42" diameter and the design he chose is lovely. (I don't have a photo of that to show, unfortunately) We agreed on a BB ply base with a walnut rim, total nominal thickness is 1" and the rim width is about 2" total with 1.5" exposed on top. The plywood is about 4mm below the top of the rim to accommodate the tile and grout. As the size of the project allowed it, other than lumber prep and creating the rim segments, the machining was done on my CNC, 'cause it was the right tool in my shop for the job, honestly.
I will state up-front that I made some errors constructing the staved rim that required an extra step to rectify, but the end result, shown here to start the build looks great. Oh, the customer will be finishing this himself.
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The design work for the segmentation and circle cutting was thus:
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The start of any actual woodworking begins with a tree. Well, a piece of one, at least. This is a nice 6/4 walnut board about 8' long.
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The board had a little bit of cup and twist, so as always, I broke it down into smaller pieces that made sense and also resulted in less waste. My bench and the CNC machines became sawhorses for this...when in Rome...
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The design in my Aspire software provided the width of the staves necessary to meet the requirements I set forth. But the software only does what one tells it to do. In hindsight, I should have created the staves wider to compensate for any "less than perfect execution" of the circle using this method. Be it known now that there absolutely was "less than perfect execution". But no matter...I did follow the plan at least but the guy who drew it, well...his pay got docked because of extra time on the job to compensate for issues. Here, the width of a bunch of plywood scraps is checked for the plan-identified stave width. These plywood pieces would be used to prove out the angles and lengths also in the design before committing to fifty bucks worth of walnut.
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I setup the small miter fence on my slider to cut the end angles of the staves. At least I thought I did, conveniently forgetting that it's half the desired angle. This is why we do test cuts with scrap...wink, wink...nod, nod...
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