Spider Box

[Dr. Deb]

You have all seen the "Spider in the Box" joke box. Does anyone know where to get the plans for one? Maybe, I should say, does anyone know how the mechanism works. The box is a piece of cake, but its getting the spider to pop out that might be "interesting."

Thanks

Deb

[Andy Dingley]

Never seen it, but I do make similar automata.

I think it's just a box, with the spider on a wire spring. Don't think of it as a "box with a spider that jumps out", think of it as "a spider on a wire above the box, that folds up when you close it".

The wire is C shaped, with a few coils wrapped in at one end to provide a bit more oomph in a small space. A couple of flat loops right at the end allow it to be screwed down (actually they're easier if they're almost-loops that don't cross, not full loops).

The spring is mounted on to the top of a block inside, against the nearside end, about 3/4 of the inner height. This allows the spider to be pushed down below its spring mount when closed.

The spring is pushed down by a shaped (smoothed off) cam block glued mid-way under the lid. The cam block rides on the length of wire below the spider, rather than the lid hitting the spider itself.

To design it, draw it out full size in side view on a piece of scrap plywood (just draw the spring mount first). Now hold a first-try wire loosely against it and try pushing it down with a cam-block, moving by about half a lid-length. Allow the wire to pivot loosely in your fingers. You might even want the rubber spider in place too, to give the real look of it.

When you're happy, then make a wire with a coil torsion spring in it, about where you'd been allowing it to pivot. fasten this to your board. Firm up the cam block design.

Draw in a box around your works.

Make a real one to match. I suggest making the base screw-on, possibly even making the first lid with screws in it for the cam block. Don't glue automata together until you've got a happy mechanism running on your screwed trial piece.

[Dr. Deb]

Thanks Andy, will give it a go. I thought it had to be something along those lines, but wanted some input before I launched out into the deep, so to speak.

Thanks again

Deb