Sheet Metal Rat Trap, Modern Version of Traditional Slate Trap.




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This is a photo record of a slate trap that my dad mad about maybe 15 years ago.

It is a sheet metal version of a traditional wooden trap known as a slate trap, I never saw one which actually had a slate as a door but i can see where the name comes from as a slate would probably have been used in the days before sheet metal was available.

I don't know if this type of trap has other names or designs in other regions. If anyone knows of any please post a pic if you can.

These would be traditionally home made from scraps of wood and all kinds of stuff, I remember seeing many different ones when i was a kid back in the 1970's, I googled slate trap and found nothing at all, It may be just a name used in my region of Ireland but the old folks that came into the hardware store i worked in all said that this was the most affective trap for catching rats..

The live rats would have been released in a open yard or grass area and would be given a chance of freedom if they could out run the farms dogs.  in the pre TV days would have been a source of entertainment, a source for wagers and a way of showing of how good a dog you had( good dogs would get the rat in less than 2 feet from the trap.

These traps have been replaced but the modern factory made snap traps and wire cage traps. Its not often you meet anyone under the age of 25 who knows what a slate trap is.

Thanks for looking, I hope this record is useful to anyone who has a varmint problem.

I have never seen a commercially available version of this trap.  My dad made this around the time he retired and it was built using a very heavy gauge galvanized sheet metal so it would never need rebuilt again in his lifetime.

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Step 1: The Trap.

The trap is designed to be a run through trap, it is placed in a known rat runs.

They would have normally had a slate (door) at each end and the mechanism would drop each slate at the same time.

I have never seen a trap that had a slate door, but i guess that the name of the trap comes from the first ones having slates in them in the days before sheet metal was common.  Any i was on local farms when I was a kid had metal doors on them.

The trap my dad mad was made from folded sheet metal as wooden trap finally get eaten away and gnawed by rats with a fighting spirit.

I find that the metal trap acts like a heat sink and the rats only survive in it during the height of summer, in winter the metal becomes so cold they don't last a few hours in it. the old wooden traps would have kept the rats alive for much longer.

Step 2: The Principle of How It Works.

The trap is sprung when the rat runs over the roller which rolls the bent nail of its axle and release the arm lifting the door and the trap shuts catching ratty.

Step 3: The Dog - How to Engineer Your Self One.

When this trap was made we didn't have a dog at the time that was any use as a rater.

So my dad engineered a dog.

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    9 Discussions


    3 years ago

    This looks great, especially since it's taking advantage of a rat's natural behavior. Would you be able to post any of the sizes, i.e. height width depth of the overall trap? We have (smaller) wood rats and (larger) tree rats here; one of the troubles I've had with other live animal traps is the mesh is generally too big for the wood rats, and they trip the trap then crawl out through the wire!

    1 reply

    Reply 3 years ago

    I figured Dr Qui wouldn't mind if I did a little 'reverse engineering' on this, so I went to a known-successful trap!a+B000LNX06C and it is 8-1/2" long x 4" wide. It is 4-1/2" high but from the image, I'm guessing that's for the C battery compartment, so I used 4" x 4" x 9" as my starting point for size.

    From the photos I used Sketchup to get as close as I could: looks like I could use a flat sheet of metal 9" x 18" and bend it into a close approximation of the shape.

    Then I built one from cardboard, and encountered a couple problems. The doors don't want to slide down properly: perhaps the angle of the pivot arm is too acute? Also, the "track" makes the rat opening narrower than 4".

    Back to Sketchup for some quick modifications and my second prototype is working better! I'll try to snip it out of sheet metal this weekend and post back some results if I'm successful.

    I haven't figured out the roller mechanism yet : from the pics, I don't recognize the roller part as salvage from anything, and I haven't come up with an easy or clever way to reproduce it. Maybe a capped piece of PVC with fins glued on? I have a bin of old printer parts here but couldn't find anything suitable. Worst case: I'll try printing something at my local library on their Makerbot!


    3 years ago

    I actually found this on the net! lol! I just had to try to find it on instructables. GREAT JOB! LOVE IT! :)


    9 years ago on Introduction

    Nice work! Although I fully support the wooden version of this just to get them out the house alive. Let em' live, but if they keep comming back their dead.


    9 years ago on Introduction

    Wonderful trap you have there I've never seen one like it before, simple design and it looks easy to reset. Good job on the ible and congrats to your dad for the job of building it. I hope to make one myself soon.
    Again Nice Work;

    1 reply
    Dr Qui

    9 years ago on Introduction


    He also made a Magpie trap a few years ago, Its an interesting trap.

    I need to pull it out of the garden as it has become all grown up by grass and weeds since and there are a couple of magpies that are becoming very cheeky  I would like to get rid off. 

    I will do a  retro how to on it also.

    bobby sissom

    9 years ago on Introduction

    this closely resembles the rabbits traps i have made for myself and family ,nice work on the photos to show how to make without having to disassemble the one you've got