Fun with geometry, no really

One of the jobs at work requires we bend some 2 inch wide strips of acrylic plastic around a 150mm (6") radius. This acrylic is 12mm (1/2") thick and very brittle. None of that is important except to say it is difficult to bend. It must be heated evenly and slowly bent at the same time. Too fast and it will shatter, too slow and it begins to melt and deform. Also it must be kept flat so it doesn't twist. The whole operation takes two people and is fraught with peril as this shit costs big money and takes forever to order in.

What was needed was a jig. A jig is a template which allows you to perform difficult or time consuming operations easily and consistently. If you need to repeatedly bore a row of 6 equally spaced holes it makes sense to take the time to measure and drill a template and then use that to reproduce those holes over and over. We needed a jig to bend these acrylic strips and I got to program my first shaped cut on the overhead router. From a slab of 2" thick board I had the machine cut this shape

"What is this!" they cried in New Factoryland, "What has the tall man made here?"

I took the part to the saw and made one simple cut resulting in these two shapes...

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and we rotate the little one...

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and take it around here like so...

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and fit it right...in...there...


The resulting gap is exactly 12mm wide. Now I know you were all asking yourselves at the start "what the hell has that V-shaped notch at the bottom got do with anything?" (I say you were). And now you see this notch has become two opposing flats for which to clamp across - that's right kids, the convenience is built right in. The acrylic is heated and the clamp slowly tightened to pull the plug into the negative forcing the acrylic to take the same shape. Let it cool, remove it from the jig and there you go - an exact 150mm radius turning through 90 degrees. Beauty.

"Hoorah!" they shouted in New Factoryland, "the tall man made a funny shape into something which helps us in our toil. What a grand trick! That bastard Grimey wouldn't have helped us, he's a right cunt."

And the tall man was most pleased as well.