constellationThis project is a sculpture based on a concept by Caroline Hearst, an autistic-awareness trainer who wanted a visual representation of the autistic spectrum to bring to her training sessions. The idea is that autism is more of a constellation than a spectrum, in the sense that it has more than one dimension.

This sculpture can represent a whole range of dimensions. There’s the obvious 3-D arrangement of the 19 balls on the ends of their springs; Caroline wanted a cluster in the centre to indicate ‘normal’ people and a few ‘outliers’ representing people who are different. Then there is the range of woods used to turn the balls; this example has walnut, osage orange, holly, spalted beech, robinia and what I think is African blackwood. These were what I had in the shop at the time. The balls are different sizes, which can indicate anything you like as well. And there is also the variation in the springs themselves. This example has two different grades of spring; although they happen to be the same diameter, one is lighter than the other so the ball wobbles further and more slowly.

The base is made from 15mm birch ply, stained with a black spirit stain, sealed with cellulose sanding sealer and finished with wax. The project is designed so that the user can arrange the springs on the base and match them with different balls according to taste. To accomplish this, I drilled the holes in the balls and in the base to the same diameter and made a plug on both ends of each spring to fit the holes. The plugs were made from polymer clay. I originally thought to use a plug cutter and make them from wood, but they were too flimsy. The Fimo works a treat.

confimo2I discovered that the lid of a Really Useful Box, the one I happen to use to keep my seeds in, has just the right sized recess. This meant that I could make all the plugs the right size by rolling the spring under the lid on a flat granite surface.  Then it’s a case of carefully trimming the clay, rolling again and when satisfied, putting the plugged spring aside for baking. The clay cleans off very easily with white spirit at the end of the session.

The sculpture has a lid for transport, made from cedar and birch plywood. I spent many holes in the night puzzling how to do this. There are two problems, first, how to get the curved shape to fit round the base and secondly, how to attach the box to the base.

bandsawcutI chose cedar because it’s light in weight and my local timber yard sells it. The height of the sculpture fits my bandsaw so I had a way forward. After cutting and gluing the cedar pieces to accommodate the desired shape I traced round the sculpture base and made another line roughly 1cm outside it.

Here’s a tip I learned the hard way. Do both the inside and outside cuts with the lid upside down. Obvious really but I didn’t see it until I realised that however carefully I set up the bandsaw the shape at the top won’t be exactly the same as the shape at the bottom, and it’s the bottom you’re working from.

cradle2The other lesson I learned (yet again) is never to throw away any offcuts until the project is completely finished. To sand the top and bottom of the shaped lid, I set up a homemade cradle on the lathe and pushed the shape against my homemade disc sander, a disc with a chuck ring attached at the back and a hook-and-loop disc glued to it. Again I was lucky, my lathe had just enough capacity to fit the whole shape within the circle. But that was when I realised I needed the offcuts, to hold the shape straight on the cradle. Luckily I had one left, the others had gone on the fire. Of course what I could have done was to sand the top and bottom before doing the bandsaw cuts; I’ll do that next time.

conboxlidThe top of the lid is a piece of 6mm birch ply. I thought about a handle and decided to just drill two finger holes, making sure they didn’t coincide with a spring hole, just in case you had a tall spring just in the wrong place. So that was what determined the position of the finger holes. I cut them with a Forstner bit, then rounded them on the table router before gluing it to the cedar. Being glued to endgrain I decided on belt and braces and put four dowels in to make sure it wouldn’t come away. Probably unnecessary, but they scarcely show. After gluing, the lid is flush trimmed on the table router and then rounded.

slotsOf course it was after that that I needed to finalise the attachment of the base to the lid, so here was another mistake. I decided on comma-shaped pegs in three places, which when open allow the lid to surround the base and when closed allow the lid to be used to lift the whole thing. Easy to operate, and no bits to lose or fiddly hinges and catches. So I’d already made three slots in the sculpture base and corresponding slots in the bottom of the lid. But then I realised there was a weakness: the wood under the slots is very fragile because of the orientation of the grain. True, the screws holding the pegs would carry the load, but in any case the endgrain isn’t terribly pretty. The matter was decided when I did in fact break the cedar when try-fitting a peg, so it was back to the drawing board. Another piece of 6mm ply came to my rescue and formed the rim at the bottom of the lid, flush trimmed and rounded like the top. I re-did the slots to the same height as those on the base but I had to do the slots from the inside relatively blind because the lid top was already glued on. So next time the rim goes on first.

conboxpegsThe pegs were adjusted by trial and error; they are each on a differently curved part of the lid so each one has to be individually shaped and its pivot point determined. The pegs are 4mm ply.



It remained only to sand and finish; the base and lid are finished with cellulose sanding sealer and microcrystalline wax, the pegs are finished with wipe-on poly and wax.