Home-made Adjustable Knife Jig

When sharpening a knife, it is critical to have the knife at the right angle. A knife jig handles this for you, letting you focus on getting the edge right. You could just buy one, but where’s the fun in that? [origamimavin] decided to make his own adjustable knife jig using bits he bought from the hardware store for $27, and which you might have in your junk pile. Fortunately for us, he’s written up the process in excellent detail, explaining the how and why of each step.

He used a couple of tools that you might not have lying around (a bandsaw and a belt sander), but these could be easily replaced with their manual cousins, or your local hackerspace will doubtless provide you access to them. Either way, it’s a simple build which could help your knives keep their clean, sharp edge for years to come.

25 thoughts on “Home-made Adjustable Knife Jig

  1. The jig is nice, but if you use it with a belt sander you will undo the heat treatment of the blade. Sure not the complete blade but the important part, the edge, is very small and easily damaged. This means in most cases the steel gets soft and you sharpness will not last for long. This issue occurs always when you sharpen a blade without coolant. Thats one reason why stones are mostly used with water or oil.

    1. Heat build up is a threat but it’s only an issue if you aren’t paying attention. Dipping the blade in a container of water nearby mitigates the issue easily.

      Whetstones don’t use water to prevent heat, if you build up enough heat sharpening knives by hand to ruin the temper you must be Flash Gordon. The oil or water is used to prevent the pores of the stone from getting clogged which decreases the ability of the stone to sharpen properly, or for Japanese stones to create an abrasive slurry that helps in sharpening.

    2. (maker of this here) I do have a bucket of water under the grinder that I dip the blade into. I heat treat the steel before grinding the blade, and since I hold it by hand without a push stick, I can feel when it heats up. You know you’ve ruined the heat treat when the steel changes colors. I’ll switch to a high grit belt to put the edge on it, then finish it off on a DMT whetstone using a small 3D printed wedge as an angle guide.

  2. Kudos to [origamimavin] that’s a quality build with a simple design that will probably outlast them and help them be productive with their time.

    Using some exact magic angle to sharpen your knife is a myth perpetuated by marketing teams of expensive sharpening jigs.

    Unless you’re making gravers, competitve chopping knives or lathe tooling the sharpening angle is pretty irrelevant. More important is that the angle is consistent. For utility tasks any angle from 10-30* will work.
    Sure some steels/heat treatments or tasks benefit from an angle closer to one end of that range than the other (kitchen knives should be 10-20*, chisels & axes 20-35*, etc) but the difference between 22* and 25* isn’t that drastic. Jigs are nice for production or when you’re learning to sharpen but freehand sharpening is a life skill everyone should learn.

    Consistency is King, not any specific angle.

    1. **RANT**
      I’ve remained silent about this for too long! I’m not picking on you, Leithoa, just making a point.

      [origamimavin] is one person, not a group. His name is (apparently) David.

      Why is it that actresses must now be called “actors”, but we can no longer use “he/him/his” as generic, singular pronouns, as we’ve done in English for hundreds of years? Stop misusing plural pronouns, people! Just stop it!

      1. I was actually really pleased to see a gender neutral pronoun used. I have a few friends who go by they/them, so I pick up on it quickly when it’s used. Just cause I identify with male doesn’t stop me from appreciating the ungendered they/ dude/ captain/ friendbeast/ etc. So kudos right back at you, Leithoa!

      2. Singular they has been a thing since the 1500’s your sensitivity to it is the only new thing.
        Even if it hadn’t English is a living language that will change whether we like those changes (literally/figuratively, also old but popularized by highschoolers) or not.

    1. DDworkrest’s angle jig was roughly the idea I was shooting for with this. The tool rest in the main image up top is his Extreme Tilt Wilmont Tool Rest, he does a great job on what he sells.

  3. its not completely clear the from the article, This is for grinding bevels, which you typically do before any heat treatment takes place, not really for sharpening because as others have pointed it will ruin a heat treat quickly. Awesome build!!!

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