How to Make a Slate Ulu




Introduction: How to Make a Slate Ulu

An ulu is a roughly axe shaped knife used mainly for processing foods and hides. You’ve probably seen flint knives before. Flint was a very popular material for prehistoric humans. When properly worked, it bears one of the sharpest possible edges. However, some cultures, such as the Inuit, did not have ready access to flint, or a similar, glassy material. Instead, these people used slate. While flint blades are made by fracturing (knapping) the stone, slate blades are made by grinding the stone, much like a steel blade. Slate isn't as hard as flint, and therefore can't hold an edge as well, but make no mistake, these blades can cut meat and hide with very effectively.

Tools and Materials:


  • Belt sander, files, or sandpaper
  • Dremel or power drill
  • Angle grinder or tile saw


  • 1 piece of slate – shingles and tiles work wonderfully for this, but you may be able to collect stones for free outside.
  • 1 piece of wood, antler, or other handle material. Waxed hemp cord, or some other string.

Safety First - Always were eye protection when working with stone, and use a respirator or other filtering mask when sanding.

Step 1: Plan Your Design

Ulus come in many shapes and sizes. This one is very compact and sturdy, but many shapes will work.

Step 2: Mark Your Slate

Use a pencil and then a nail to make an outline of the blank you want to cut.

Step 3: Cut Out Your Blank

Using the grinder or saw, carefully cut out your blade blank. Be patient. Stone is brittle, and a high-speed cutting tool could break it.

Step 4: Shape the Blank

Using a belt sander or some other form of abrasive, grind your blank into its desired shape. Again, be patient, so you don’t snap your blade. You want to have a very sturdy edge, so don’t make it too thin. If you are familiar with knife making, you want a convex edge. If you’re not familiar with knife making, you want to make the cross section of the blade look like a parabola, rather than a “V”

Step 5: Sharpen

Using progressively finer sandpapers, sharpen your knife. Don’t forget to periodically brush or blow the dust off of the paper. Slate isn’t as hard as flint, so you won’t be able to put a razor sharp edge on this knife, but it can still get sharp enough to cut vegetables, meat, and even leather. Keep in mind that this edge won’t be very durable. However, as you’ll see in this step, it’s very easy to resharpen..

Step 6: Wax

This step is just to make it look pretty. I used food safe countertop wax to coat my ulu. It gives the stone a nice shine, and a little protection.

Step 7: Make the Handle

While the ulu could be used without any limitation at this stage, it’s a nice touch to add a handle. I chose to use a bit of elk antler, but just about any material will do. Simply use your dremel, power drill, or chisels to cut a slot large enough to hold the base of your blade.

Step 8: Attach

I’ve used hemp cord to fix my handle to my blade, so that I can separate them if the stone ever breaks. If you wanted to you could use some type of adhesive or even pine pitch or hide glue. Drill a hole through the handle, and one to match through the stone. You’ll notice my blade has 3 holes. 2 were pre-drilled because I used a slate shingle. Next, carve some grooves in your handle to hold cords in place. If you choose to use adhesive, this step is unnecessary. Finally, bind the blade to the handle using the cord.

Step 9: Complete

Congratulations, you now have your very own slate ulu! Time to bask in the glorious anachronism of modern technology producing stone age tools! As I’ve said before, slate knives can be used for many cutting tasks. While the edge will wear out more quickly than most knife materials, it's very easy to resharpen. Experiment with different shapes and cutting angles for different applications.



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    20 Discussions

    Could I use this as an axe to cut and shape wood?

    Heya, lovely product, however may be worth writing a health warning on this- slate dust can result in pretty nasty respiratory illnesses, silicosis i think... pretty common in slate mining communities. Be careful hon!

    3 replies

    I didn't even think of it. I always wear a mask when sanding. I don't think there is a healthy dust to inhale.

    My uncle's grandmother of my grandfather's father of his mom used to make this for sale :P

    1 reply

    The grandfather of the neighbour of my cousin's girlfriend's mother in law's greatgrandfather had a friend who lived next to a guy who knew someone who bought one from the relative you mention. He passed it on and it is still sharp

    Great Instructable. The Ulu is a great multi-purpose utility knife (doesn't seem so great if you have to stab game to death with it), and is an excellent blade to keep around in a kitchen. This is definitely an Instructable to try

    Nice! I used to live in the far north, where ulu knives were common. Very handy knife for food preparation. I'm looking forward to making my own slate ulu.

    Are you one of those anti-twigist folk? Maybe you should just keep banging the rocks together.

    As a kid I made arrows from Willow, Chicken feathers, and Slate using a file to shape the points. They looked good but the points would shatter if they hit something too firm. These I fired from a dried Willow bow. ~:- } Yup.

    Interesting, I think its a pretty decoration, but useless as a cutting or survival tool. I've worked with slate shingles many times and know how soft and fragile (see the pieces in the 5th photo) they are, a slice of hard bread would be almost as useful as a cutting tool. Have you tried to use it? Sorry, but practical and useful are more beautiful to me.

    Although I've never tried to make an ulu, either decorative or useful, I think that you could of shaped the blade and chipped the edge by hand, instead of using power tools, and it would have been sharper, quicker, easier to make...uglier, but more authentic looking, more "vintage". I haven't tried it, but a slightly curved gouge type of wood chisel might produce a more "chipped flint" type of look for the edge.

    When we roof houses with slate all the tools necessary to reshape, resize, and install the factory shingle (like yours) are an awl for making new holes, a hammer with a sharp edge for scoring and breaking, and a pliers type of clipper for finer shaping work, and are carried in our tool apron, no power tools needed. We have to do do it quickly, many times a day, to make a buck. There are also a lot of other specialized hand tool and power tools available that are not absolutely necessary, that do prettier and more precise work. Of course, if I had a "hammer with a sharp edge", I wouldn't need a ulu, would I?

    BTW, where is the "twig"? I didn't see it in neither the production nor the product and, as you pointed out, the handle is not necessary for the ulu. The lever and spring on the clamp to hold the unnecessary sand paper was as close as I could see. Production looked more like "wheel" tech to me...lots of "wheels" used. I would also like to point out that the twig is unnecessary for a knife, a string or leather wrap was more likely used for the first knife handle.

    Ok, my turn to get fanciful.. I suppose you could argue that the wheel was twig tech because there is a high probability that the first one was made from a log, big stretch to consider logs as twigs. I believe that the knife tech is based on ramp tech....tapered edge allows the knife to slide in (cut, penetrate) more easily and were probably first made from animals teeth, bones, and antlers, and later replaced by stone for durability, weight, and sharpness. I believe monkeys also use rocks as tools too and has a high probability that it was used before twigs and presented the inspiration for the wheel for man after observing how easily they moved downhill (took a long time to realize that it needed a hole in the middle and an axle to be useful for more than a roller). The spear/axe was probably the first marriage of 2 different techs, ramp and twig (lever)? The knife might be considered a marriage of ramp and lever tech because it can be used as a lever? Perhaps there are other possibilities beyond what Douglas Adams presents. My guess is that a solid log was the first boat (somebody climbed aboard one to keep from drowning and had an revalation), not a bunch of twigs. I suppose I should read his book before I spout off any more. It sounds a little fanciful like "Operating Manual for Spaceship Earth" by R. Buckminster Fuller and his "Great Pirates" concept of mankinds history, possible theory, maybe even probable, but not proveable. Whoa, got to come back down to earth now and get something done.... maybe not.

    3 replies

    Okay, I'll try to address all of your concerns! First, as mentioned in step 5, this knife can cut through a surprising variety materials, including leather. Of course it's never going to be a scalpel, but it can easily cut up meats and vegetables for cooking, which was its original use. Additionally, they can be used for skinning or scraping hides. Obviously a harder, sharper material would be better, but if you're only concerned with practicality, wouldn't you just be using a steel knife anyways?
    Regarding the methods used to shape the blade, I chose to use a belt sander for the speed. It just gets the job done faster. It also allows me to get precisely the edge I want. I wouldn't choose to chip the blade on this. The crystal structure of slate is a little different from that of flint. Instead of breaking in those nice, curved shards, slate breaks along a plane. I'd just end up with a stone that will split apart like a deck of cards. Using the curved chisel might work, and it would definitely look cool if the stone doesn't split, but I'll be surprised if it's quicker to make or maintain. If for some reason you needed to make one in a survival situation, you could do so by grinding in against different stones. The benefit being the simplicity.
    Concerning the "vintage" quality, There's evidence that some ancient cultures really did use ground slate knives like this, rather than (or possibly in conjunction with) knapped knives.
    Finally, the twig technology quote. I like how it over-simplifies what a huge development tools were for us primates. I admit that it doesn't mesh perfectly with the topic, but it was just too funny for me to get out of my head. It's a great little book, but it's really about conservation, not evolution or anthropology.
    I hope I've answered all of your questions satisfactorily. Let me know if I can clear anything else up!

    Don't get me wrong. For me this is all about the novelty. Stone knives are cool, but steel is my tool of choice. It's exactly the same way I feel about fire starting. Fire bows and flint and steel are awesome, but if I'm actually going to light a campfire, chances are I'll be using a 50¢ bic.

    Sorry bout that, got out of bed, got spaced out and started rambling. Need to wake up and get some tea.

    I find it somewhat paradoxical that in order to build a caveman's axe one should use 21st-century high-tech tools.

    Ive never thought of using slate,this is a good bit of info,and will I will be trying a couple of things,great job on the Ulu,top notch.

    outstanding! I have some scraps of slate I can use for this. :D

    I don't want you to think I'm having a go at you but I must reiterate the warning about wearing a mask. I'll be having a go at hand napping & grinding the blade outdoors so the risk is much lower but I will have a mask to hand. If you're not sure if a mask is needed or not for the work you're doing with slate or flint wear a mask to be sure. The very mild discomfort of wearing a mask is nothing weighed against Lung Fibrosis.

    thanks great ibble liked the journey. just broke a small hatchet. like the idea of a ulu for use but the steel head will allow me everyday use.

    That's okay, I understand. If you aren't familiar, Douglas Adams was a comedy writer, famous for Hitchiker's Guide to the Galaxy. He wasn't exactly a biologist. Anyways, it was really meant more to illustrate how humans used tools to differentiate themselves from animals.