After the success of my miniature bear trap build I had plenty of requests for a miniature keyring mouse trap. It took 5 revisions before I got something I was really happy with, this is that build. Free plans at the bottom of the page as always… Enjoy the build video below.
Miniature Mouse trap
A basic mousetrap is already a very simple thing but I really did enjoy trying to re-make it as simple as possible. This build is all made from bits lying around and uses no power tools. Apart from the springs which we will get to later, but these are easy to make as well.
To keep the appearance of scale the wooden base is only 2mm or less thick, this is because it is made from a scrap of hard wood. A soft wood could also be used but I wanted to make the strength of the springs a little snappy, so I didn’t want the mechanism to pull out any of the pins with the force. The pins used are 1mm panel pins (nails). I drilled the holes at 1mm by hand with a small drill chuck, but you could even just wrap some masking tape around the shaft of the drill bit to get a better grip on it. Superglue helps to keep it in place. A nice scrap of hardwood like ebony would have looked great but I didn’t have any.
The wire used for rest of the mouse trap mechanism is all 1.2mm piano wire, although any stiff wire also works fine.
The trigger lever for the trap is just a tin can lid because it’s thin, it can slip off the pin very easily giving it a hare trigger. I did upgrade this in my dual spring trap with a little bit of stainless steel I found. This is so if got struck with the extra power during use it was less likely to bend out of shape.
Miniature mouse trap springs
The torsion springs used are 180 degree torsion springs. You can buy them on eBay or make your own. If you want to buy them you will need a minimum of 4 coil turns with a wire diameter of 0.3 to 0.5mm. Ideally with an internal diameter (id) of 3 to 5mm max. And of course it will need to be a 180 degree spring.
The DIY springs are made with piano wire or spring wire and eye protection should always be worn! You can also find this wire in craft stores and eBay, and no more than 75mm is required to make a spring. Again 0.3mm to 0.5mm wire is perfect.
In the video I wrap the spring wire around a larger piece of wire held with some hand pliers. Later on I found a better method was to wrap the spring wire around a 3 or 4mm drill bit shaft held in either some vice grips or a bench vice. You need 4 complete turns with the wire coils kept close together so it looks nice. I stopped wrapping the last coil when the spring had a relaxed resting position of 180 degrees.
I payed special attention to the direction of the coil wrap so the the spring legs are correct for the side of the mouse trap I wanted to fit the spring. On the more powerful 2 spring version you can see in the video they go in opposite directions.
Miniature mouse Plans
All plans are free to download as always.
The above project is aimed at adults for education and entertainment purposes only, not to replicate. Anyone doing so takes full responsibility for their own actions.