Saturday, 10 May 2008

My Desk - making it happen

Apart from the desk top, it's all rectangles. To look good, all those rectangles need to be cut accurately to size and squarely. I have a circular saw that cuts reasonably straight, but the propect of carefully marking up and cutting all 36 rectangles from large sheets was enough to put me off ever starting the project. Plus the circular saw doesn't cut a very neat edge. This is where the cunning plan comes in...

Ridgeons, where I was planning to get the wood, has a large wall-mounted saw which they can use to quickly and accurately cut sheets of wood. I reasoned that if I made a cutting plan for the required number sheets, I could pay Ridgeons to do this bit for me, and then all (all! hah!) I'd have to do would be to fix the rectangles together to make a desk.

I like oak, but solid oak is expensive and would probably split or warp if I tried to make a desk out of rectangular panels of it, so I opted for oak-veneered MDF, as used in the construction of the Billy bookcases. Ridgeons sell it in sheets of 2440mm by 1220mm, so I set about arranging the required rectangles onto sheets, trying to minimise wastage and number of cuts.

At first I tried to use Sketchup to rotate all the rectangles into the same plane and fit them to sheets, but that turned out to be quite tedious, so instead I manually copied the size of each rectangle into a spreadsheet (hiding each in Sketchup as I copied it to avoid missing or duplicating any), then used OpenOffice Draw to create a 2D drawing of all the rectangles (labelled and colour-coded for easier checking), and arrange them onto sheets. Here's one of them:

The chap in the timber cutting section at Ridgeons told me to allow 4mm for the cuts, and explained that it's difficult to make cuts that stop part-way across a sheet. The small white circles on the sheet above are numbers, indicating an order for the cuts that ensures each is a cut right across a sheet.

The shape of the desk top I would need to cut myself, but I thought I could manage that as it would only be a small number of cuts. The top would be too large to cut from a single sheet, and also too large to fit in my car, so I split it into three parts, and added rectangles of the required size to the cutting plans.

I chose sheets with crown-cut veneer, which has nice patterns in it, on one side, and cross cut, which has a plainer pattern, on the other, planning to use the crown-cut as the more visible sides of the desk.

I took printouts of the cutting sheets (four in total) to Ridgeons, and they quoted me a discounted price of £15 for the cutting, and about £250 for the wood. £15! A bargain! Think how long it would have taken me to cut them myself!

I collected all the cut rectangles (and the off-cuts) a day later, and took them home in the back of the car (a hatch-back, with the back seat down). The spreadsheet of rectangle sizes was useful for checking everything was correct. In general, the accuracy was pretty good. I found two or three dimensions that were 1-2mm out, which was a little disappointing, but will probably be ok.

Another slight disappointment was that the sheets had been cut with the crown-cut side on the side of the saw that produces more splinters, and for the cuts that went across the grain this meant the edges were quite ragged. As a result I decided to use the plainer cross-cut sides for the more visible sides of the desk, hiding the more ragged edges.

The final disappointment was my fault. I put the rectangle for the filing-cabinet top onto the cutting sheet the wrong way round, so the grain goes the wrong way when compared to the desk top. If this looks too bad then I could get another one cut (perhaps with some more rectangles for future projects...), but I might just leave it as one of the "features" of a piece of home-made furniture (and it won't be the only "feature"...).

Next-up: fixing the rectangles together...

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