Automatons, kinetic toys and the piano player

Posted by jerry on January 1st, 2007 — Posted in DIY, Journal, Woodwork

One Christmas gift was a book on making whirligigs and kintic toys – now this looked like great fun! So, armed with some scraps of wood and the book, I headed out to the shed to see how difficult it would be to come up with something…

One of the pieces in the book was a crank-driven piano player. And there is a reason I chose this one.

You see, my grandfather used to play piano. He played entirely by ear – he could go to the movies once and come home and play all the main theme tunes. And he used to play down at the local pub as something companionable and fun to do. Interestingly he was a teatotaller, and the top of the piano would fill up with pints of beer that people bought him – and they would remain there all night as he played all the old favourite sing-along songs of the day. I guess that’s where I inherited my music ability from. So with that in mind, I thought I’d have a go at a piano player.

By the end of the evening – about four hours, I had a ‘proof-of-concept’ version that looked like this:

piano player automaton

Using a hole saw I cut out four 4cm (1 1/2″) discs from some scrap pine. I then drilled them to accept thin dowel in an offset from the centre hole, and used three of these discs to form the crank. I also cut two small discs of 1cm (1/2″) to act as spacers to stop too much lateral movement of the crankshaft.

I then made up a simple ‘stage’ from three pieces of white melamine chipboard and another piece for the piano upright.

I cut out and roughly shaped the head and torso of the pianist from some scrap pine and then cut out the arms and legs with a scrollsaw. It was important to put an angle on each thigh as the legs need to splay outward to enable the control wires to pass between the legs and attach to the wrists to provide the movement.

The wrists were drilled and the arms and legs attached to the torso. The nail holes in the arms and legs were drilled larger than the nail so they would move freely when attached – the nails are only holding into the torso.

The seat is just a small block dowelled into the stage, as is the piano. Once in place, positioned either side of the line of the crank I drilled two holes inboard of the arms into the stage to allow the control wires to pass through the stage to the cranks.

I then drilled (slowly) an oversize dowel hole in each end of a large popsicle-stick and cut it in half. Then I drilled a small hole at the other end of thepop stick to accept the wire. Then I fitted them to the dowels as I assembled the crank.

The fourth disc I used as a spacer for the handle. I then cut a larger disc of 6cm for the handle. I then drilled near one ege to accept a small brass cupboard handle.

After doweling the pianist loosely to the stool I took a couple of pieces of fine piano wire and attached it to the pop-sticks on the crank and fed them up through the holes and finally bent them through the wrist holes.

Once I had established that the hands would move up and down I then clad the piano in some thin pine offcuts, provided another block for the keyboard, attached a couple of ends and printed out some keyboard line-art and glued it onto the keyboard block.

Then with a nod to my late Grandfather I made a beer mug from some dowel with a pop-stick handle.

And here is the result

piano player automaton

Click here to see it in action – complete with the crank mechanism!

You can get more information on automata like these at Automata.co.uk This one has good information on how automata work – their mechanisms and how to design your own.
And there are some great online displays of kinetic toys, such as these:

Cheers
Jerry

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