Tuesday, 6 January 2015

Cat and Mouse

Hi all,
Whilst making the Hare Musical Box for my wife, I also carried on making the Automata that I started a few weeks earlier. In fact, I used it for an excuse for spending so much time in the workshop whilst secretly making her box. In my last post on the subject, I showed you the parts that I had cut out.
I was quite excited when the time came to build it and stick all the pieces together, but my happiness was rather brief. I thought I 'd done an excellent job when cutting at the parts and that the automata would work like a well oiled machine. To be honest, it didn't work at all. It looked like the dog's do dahs but mechanically it was crap.
When the crank is turned the mouse is supposed to go around on the turn table while the cat's paw goes up and down to try and catch him. To add to the effect, the cat's tale also goes up and down. That's how it is supposed to work but mine didn't. The turn table wouldn't turn and the cat's paw and tale didn't go up and down either. If you want to see how it should work or want a copy of the free plans here is a.

There were two main reasons why my automata didn't work. Firstly, the plans said that the parts should be cut from 4mm ply, but I hadn't got any so I used some 6mm off cuts that I had hanging around the place. After all, one of the main reasons for doing an automata was to use up some of the off cuts that I'd been accumulating. I reasoned that 2 mm wouldn't make any difference but it did. The other issue was that I wasn't careful enough when cutting out the cams and drilling the holes through the centre. The cams weren't smooth enough in profile and the hole through the centre was slightly angled.

The cat's tale and paws didn't drop after lifting either because they seemed so light. I fixed that issue by winding some fuse wire around the ends and painting it white and after modifying the rest of the mechanism as well as I could, I finally got the thing working, a bit jerky in operation, but working.
Here is a picture of the inner workings.

My conclusions regarding automata are as follows: Cutting out the parts and following the plans can be quite interesting and rewarding. It also provides an opportunity to use up some off cuts and examine how mechanisms work. However, making automata is time consuming and if done badly it can lead to frustration. There was a point when I felt like chucking my own do dah's at the clock but I got over it

Anyway, at some time I may try doing another one, but it won't be in the near future. By the way, I've change my free book offer, click here to go to my book website if you are interested.

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