Brighton 75A: Today's post 131227: Assembling the first baseboards
Entry posted by NorthHighlander
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This is how I launched into the making of the first baseboard(s). The first stage was to load the Templot templates on to an 8x4 sheet of 6mm ply for a repeat of a previously abortive effort. This time I followed Martin's advice and printed the templates on 160gsm card on an inkjet (i.e. not laser) printer. I used 3M spray mount to fix the templates to the board. The spray mount allows repositioning and does not distort the templates.
Once laid out properly (and it is amazing that, no matter how careful you are in positioning the templates, when you have a large area to lay, you get out of line fairly rapidly!) the board positions were drawn on. I could have done this using Sketchpad in Templot, but I wanted to assess the board positions in the whole to get the boards of broadly similar sizes. This proved to be difficult in the event so there are some large boards (none longer than 6 feet) and some small. Clearly the fewer boards the better to avoid baseboard joins and alignment problems, but needs must given the requirement to transport the layout to various exhibitions.
I used a green fine point felt pen to mark the outer edges of the baseboard units and a red line 6mm either side of the green to show the cutting line (the baseboard unit has a framework of 2 x 6mm ply, the baseboard top fits inside the outer plywood uprights).
I make absolutely no claim to this baseboard design. Chris Yates, who should take the credit as mentioned in earlier blogs, has shown a large flat table he has constructed to assemble the boards, laying the baseboard top on the table and holding the side members upright with a series of clamps. I discovered these are called 'toggle clamps' and come in vertical or horizontal versions. I purchased horizontal ones as I figured that these would be screwed to the top of a solid vertical piece of wood. Following an episode with a Chinese vendor on eBay (actually positive!) which would fill another blog, I ended up purchasing four horizontal and eight vertical clamps.
Because of the very irregular shapes of the board, rather than screwing them to one long piece of wood, I decided to fix each clamp to a 110mm long piece of 100mmx50mm timber which itself is screwed to a 100mm square piece of MDF. Some years ago I built a jig to construct baseboards using the geodesic principle and I have used this substantial jig that comprises two long pieces of 100x50 to which are screwed parallel pieces of 45x20mm strips at 50mm centres. The toggle clamp mountings were designed to be able to form curved side members to the baseboard top and these will be fixed to the 45x20mm members with M8 bolts. In practice, there is a slight deflection in the 45x20mm lengths and this is compensated with clamps to make sure that the table is flat.
Using Chris' dimensions, a friend used his table saw to cut up half the sheets of 8x4 (2440mmx1220mm) 6mm ply from the six sheets obtained and delivered from an excellent and traditional woodyard in Wick into a series of strips 114mm wide (for the outer side members) and 108mm (for the inside).
This photo shows the assembly using the toggle clamps. I have taken it slowly, fixing one side member at a time and letting the glue set for 24 hours. Already, the board is rigid and that is before the second 6mm side member is fixed to the first for final rigidity. The clamps work well, but alignment is assured by using other sorts of clamps to hold the whole thing together and flat while the glue sets.
This next photo shows the vertical clamps in action securing a curved side member in place. It also shows that I have strengthened the top sheet with some strips of 6mm ply at approximately 300mm centres. They are fixed to avoid point motor positions, hence not being parallel to each other.
In the next blog I will show how the construction progressed.
Regards
Tony Hagon
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