Ultra Cheap PCB Wrenches Make Perfect Kit Accessory

Let’s make one thing abundantly clear. We do not, under any circumstances, recommend you replace your existing collection of wrenches with ones made out of PCBs. However, as creator [Ben Nyx] explains, they do make for an extremely cheap and lightweight temporary tool that would be perfect for distributing with DIY kits.

This clever open hardware project was spawned by [Ben]’s desire to pack an M3 wrench in with the kits for an ESP32-based kiln controller he’s developing. He was able to find dirt cheap screwdrivers from the usual import sites, but nobody seemed to stock a similarly affordable wrench. He experimented with 3D printing them, but in the end, found the plastic just wasn’t up to the task. Then he wondered how well a tiny wrench cut from a PCB would fare.

The answer, somewhat surprisingly, is pretty well. We wouldn’t advise you try to crank your lug nuts down with one, but for snugging up a couple nuts that hold down a control board, they work a treat. [Ben] came up with a panelized design in KiCad that allows 18 of the little wrenches to get packed into a 100 x 100 mm PCB suitable for production from popular online board houses. Manufactured from standard 1.6 mm FR4, they come out to approximately 10 cents a pop.

Since [Ben] has been kind enough to release his design under the MIT license, you’re free to spin up some of these wrenches either for your own kits or just to toss in the tool bag for emergencies. We’d love to see somebody adapt the design for additional sizes of nuts, or maybe figure out some way to nest them to sneak out a couple extra wrenches per board.

We’ve seen plenty of folks make cheap tools for themselves in the past, but projects that can produce cheap tools in mass quantities is uniquely exciting for a community like ours.

41 thoughts on “Ultra Cheap PCB Wrenches Make Perfect Kit Accessory

      1. I’m over 50 and still own metal tools owned by my grandfather, then by my father. So, yes, there is environment impact, but not comparable to the production of something that breaks so easily.

        1. I still just borrow any tool I don’t actually own from my neighbor. He’s got a great selection, lives across the street and is always super nice to talk to. In addition, he always has helpful advice for me to repair anything being my own ability. No need to buy it make a tool when it’s been made and sitting in his toolbox for decades. I know I’m not the only one who borrows tools, others borrow from me as well. It seems a far better solution than making a fragile and polluting hack just to tighten a nut.

        2. And here’s where the economy breaks down, I still have a set of kitchen utensils from
          My grandfather and his father, stainless steel riveted or spot welded and although some of them have been broken due to occasional “extreme duty use”, they all were repairable.

          The current day plastic crap that you buy might cost you a quarter the price but will never last.

    1. A quck search for something like “18 In 1 Snowflake Wrench” will get you a device , in metal, that will cover most needs for a few pennies. As he’s already sourcing a ‘cheap’ screwdriver anyway…make a happy customer with a half useful tool for free :)

  1. It would be easy to determine the amount of torque needed (say lb-ft) to strip the jaws of this thing by fixing a nut against another nut on an M3 bolt held in a vice, and extend the handle out to (for Imperial measurement users) 1 foot horizontally, then keep placing weights on the end of that until it gives way.

    But really, it’s a gimmick. Use the proper tools for the job, which is what people building these sorts of kits will very likely have. Just make it clear and indicate what tools are needed to build it, people won’t be offended.

    1. Yes so when you buy that ikea desk, throw out all the tools that came with it and then go down to Home Depot or Loiwres and spend $500 or maybe even $1000 and get the most proper tools to assemble your desk. Oh yes and of course every college freshman is going to head off to college with their $1000 tool kit so they can put together their new desks. What, you mean you are not carrying a full $50 set of Kline metric allen wrenches on you at all times? Shame!

      1. It’s more like when you buy that Ikea desk, chair and shelving unit, throw out the two of the three tools you don’t need because they’re duplicates. And then you have the tool, so all future Ikea kit then comes with useless tools.

        Get a cheap set of spanners, allen keys and screwdrivers and you’re pretty much set for most things for life. You’ll probably get change from a $20.

      2. Those “included” tools are never free.
        It does cost money to make them and time and effort to package and bundle them with the product.

        Ikea furniture is an excellent example.
        If you go buy a bunch of closets, there is no need for each closet to have it’s own toolset.
        I’d much rater that they sell some simple tool sets separately, and then print on the label which toolset you (may) need for that piece of furniture.

        I usually throw those included tools in the bin straight away. sometimes I open them to marvel over the low quality standards of those tools.

      3. I do the worst of two worlds!
        I tighten the screws of IKEA hardware not with the bundled allan/hex/imbus key, but with a proper screwdrhammer drill (hammer function disabled), with a torx bit in it – I find those easier to put in and get out the screws than the “proper” hex bits.
        I don’t ever use this size torx bit for anything else anyway – torx screws haven’t really caught on in the Netherlands, mostly still pozidriv.

  2. M3 is quite often a bit problematic.
    The smallest wrench in a set very often is 6mm (which is never used) while M3 is 5.5mm

    So I was quite happy when I found a wrench that is 5.5mm on one side, and 7mm on the other side, so it works both for M3 and M4.

      1. I know they exist, and are easy to find when you go looking for them, but that’s not my point. If you just go buy a regular set of general purpose wrenches, then 5.5mm often is not included.

  3. This is a totally excellent alternative to the disposable tools that come with stuff. You can even make wrenches of unusual shapes and sizes to fit in those awkward places. Much better than telling people to go out and buy an expensive tool that will only be used once. A toolbox full of unused tools, used once or maybe not at all, is a massive waste.

    1. I really like the idea.
      For me, a kit should come with everything included – and attention to details matters. I would not need the 2 cable ties in a kit, but having them right there in the right size is good! I don’t need another inbus/hex/allen key, but if the right size is included, all the better!
      In contrast, for a “diy inspiration” project I expect to use my own tools, materials and probably buy some more.

      If a kit needs a wrench, then there should be one.
      It will probably get thrown away like all the packaging – so whatever works is best. I don’t need a snowflake wrench for 2€ (which is still crappy and will be thrown away) if a 10ct piece will do.

      +1 for the rounded handle

  4. Could also possibly turn the other end of the PCB into a male USB plug if the PCB is the right thickness.

    Might be useful for thumbdrives (instruction manual?) or UV LED (e.g. curing lamp for a 3d DIY resin printer kit?)

  5. Anyone know if that textured line surface finish is just standard matte black solder mask? Got an adafruit board recently that had it and I really like it. My last matte black board from ages ago was like a dusty matte and I wasn’t that impressed.

  6. Is this

    ” …. Fiberglass is the worst material to make a tool from”

    an opinion or do you have evidence?

    I have plenty of tools which are made of fibreglass in whole or in part because I need non-magnetic or non-sparking items. They do their job when used appropriately. I also have a fibreglass handled maul which puts up with severe, really severe, impact usage and has worked very well for over 3 years now. Fibreglass seems to be an excellent choice for the handle – far better than metal or wood. This PCB wrench seems to be a jolly good idea which would certainly make more convenient an assembly process.

    Please do consider clearly indicating whether you have actual expertise in a subject or are just making an opinionated comment.

    Toodle pip

    1. I generally agree. In this case I think about climate change and pollution and would prefer not to distribute extra FR4 to be thrown in the landfill when I’m sure the swarf gets recycled in fabland. It’s not a throwaway material to be thrown into kits, unlike wood/bamboo/recyclable plastic.

  7. I think a lot of people are missing the point. When you panelize, you often have extra material left over. You could put a small project like this in to take up the space. Then you are using that portion instead of throwing it away.

    It could also act as a torque limiter because of its fragility and short handle length. Plus, there’s plenty of room to expand and add value. You could have a series of hex sized holes at the end and use whichever one you need. If you make the material thin enough, you can have built-in bend points. Perhaps have it torque-limit with a bend point – twist too hard and it bends instead of turns. All kinds of things you could do. Plus it could be a good branding opportunity. This is hackaday, so hack it up.

  8. This isn’t so bad, and slim wrenches are pretty hard to find. One time I commissioned a laser cut slim wrench in steel because I couldn’t find a slim enough wrench to fit the space. I think the wrench should generally be up for the job. It can be even stronger if you make it a closed end wrench. I’m not a fan of using PCBs for disposable tools but if you have extra panel space why not.

  9. You could make these with Al pcbs too. More durability perhaps. allpcb can do them very cheap.

    About total $77 for 1000 pieces (0.08/pcs), 2mm thickness, 1.5 cm x 8cm. Pretty cool.

  10. I already use proper (steel) tools, but I can see a version of the hex head of this being used separately as a way of producing a (semi-)captive nut on the back of a PCB – where my fingers are no longer nimble enough to reach.

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