Grinding your Blade to Shape

Grinding your Blades


With the forging complete, it's time for shaping the blade to its final form. Techniques vary, especially across the different tools, which I will cover one by one, but as a general principle; grind evenly, be precise, be symmetrical, and grind thin; the more acute the angle, the more efficient cutter the blade will be. Especially if this is your first knife, the forging probably wasn't a perfect match to your design. If you can still match it through grinding, do so, but otherwise, be willing to modify as need be, then redraw the knife, modifying the handle to match the new blade.

Profiling
 



Profiling is refining the blade shape in two dimensions. Use a sharpie to mark where you need to grind away at; I find cutting out your design and tracing it onto the blade works quite well. If you have to modify apart from your design, do so, making sure the lines you draw are exact. I personally do less drawing and more eyeballing as I go, so I can see what makes better flow, and catch any mistakes by looking at the "bigger picture". There are no really special techniques for profiling; if you use a file, put it in a vise and even, swooping strokes in a diagonal direction, pushing along the length of the blade. For finger choils and tight rounded parts you'll need a round file for sure, whether you have a powered grinder or not. For a grinder, put the blade flat on the rest, and grind from there.
An angle grinder is a little trickier. Clamp down the blade, with the edge needing to be ground protruding over the edge of the workbench. Watch out, by the way; angle grinders get things hot and you don't want to set fire to your workbench. Use a flap disc, as rough a grit as you can get, and refine the shape from there, running back and forth along the length of the edge, so as to keep things even.

If there are really large chunks of steel that need to be gone, cut them off with a hacksaw, or if you have one, an angle grinder with a cutoff blade. Be careful when cutting with an angle grinder; flex the blade too much, and it'll snap, sending shards of it flying across the room. You do not want to get hit by that. You'll probably do a lot of cutting steel with an angle grinder at different points in knifemaking, (especially if you try stock removal- making a knife without forging) so just keep this in mind: a thinner blade will cut faster, as there is less material in the way, but is more likely to break if you don't watch what you're doing. Get a medium thickness blade, but more on the thicker side when starting out.

For the tang, there should be less mass at the end than at the shoulders (where the tang stops and ricasso begins). It doesn't need to come into a sharp point, but it should definitely taper, in both width and thickness. The shoulders should be wider than the tang by about an eighth of an inch or so; remember, the handle should be as wide as the ricasso.

Beveling


This will be the majority of work and time. Trick here is to go slow, careful, and make sure everything is even. A good clean grind is half the look, and use.

Beveling with a file

Whether using a file or an angle grinder to bevel the blade, I always clamp the blade onto a length of wood, which is then clamped (pointing towards me) to the workbench or in a vise. Using a sharpie, find the center of the cutting edge and draw a line along it. This will be your guide on where to stop; file away until only the black along the edge remains. Coincidentally, the thickness of a sharpie mark is about as thick you want the edge to be before heat treating.

Use a sharp file, Nicholson is a common favorite, and begin filing, pushing from tip to plunge (part where the bevel ends) diagonally. Lift up, bring back to the tip, and repeat. Clamp a block of some sort over where you want the plunge to be; this keeps you from going too far. A symmetrical plunge is one of the defining characteristics in a good blade. Be patient; this will take a while. The blade likely will not need much thinning in the back, just towards the edge. Don't make the slop convex; you're going for a flat angle here. Push, stop, lift, bring back, and repeat. Get every bit of black out. Your finished blade should be completely silver. It's tempting to make it rustic (there are plenty of beautiful knives that feature forge scale), but at this point, you're working on commitment, and for a beginner, knives without forge scale will look and perform much better.
When you reach the centerline, flip over, clamp down again, and repeat. If you can finish the blade clean, flat, and with uniformity and symmetry, it will be a beautiful blade.

Beveling with an Angle Grinder



Using an angle grinder is fast, by tricky and very easy to mess up. Use a flap dis, as rough a grit as you can get. Set up the blade the same way as you would as if you were filing, and make sure you have a plunge block on (I just use a clamp). Draw on the blade the boundaries for grinding, with your goal to grind away only the color and that's it. I start in the middle of the blade, go the the plunge, then back to the tip, and back to the plunge and so on. Don't put much pressure; you're going fast enough as it is. Keep checking all around the blade to update the amount of progress you made, so as to not grind too much in one area. Go slowly. When I say slowly, I mean don't rush the process; in actual use, I use a back and forth motion almost as fast as if I were sanding. Moving over a large amount of material in a small amount of time reduces the chance of one spot getting ground too far away compared to another spot. Going back and forth in easy motion makes it more even. Get close to the centerline but not quite on it, then flip over and repeat. Watch out; there is a lot of friction so the blade gets very hot. When the blade looks even and you have the majority of the grinding done, switch out discs for something at about 120 grit. Go over it, smoothing things out and making sure there are no deviations from the desired grind. Once you're done here, cool the blade, and finish it up with files, smoothing everything out and making sure no marks from the angle grinder show up. The goal here is to make it look like you did it all by file.

Beveling with a Belt Grinder
 


By belt grinder, I'm also including here disc grinders and belt sanders, pretty much anything with a rest to put the blade against. The nice thing about these, is they're easy to get exact, and not so fast that you mess up before you realize it. Use the coarsest grit (lowest number) you have. I like to make first contact near the center of the blade; this makes it less likely to go too far at the plunge, or at the wrong angle near the tip. From there I got back and forth, watching carefully to make sure I get the plunge right.

Go to the centerline, flip over, and repeat. Don't let the grind become convex; if it's flat, it'll look way better, and be a more effective cutter. Keep careful attention to make sure the cutting edge isn't wavy; it should be completely straight from plunge to tip. By the time you're finished grinding, it should be about the thickness of a quarter. Normalize it once, then it's on to heat treating the blade.

 

Gunk Bucket

The gunk bucket is just a bucket of water, clean whenever I replace it but soon to be filled with who knows what. It's the do-everything coolant, does everything from catching the steel sparks, to cooling an overheated blade. It's also an emergency fire extinguisher, should the need arise. Always keep one around, but be careful not to drop something in it by accident; it's not very pleasant to fish around in. I keep mine underneathmy belt grinder, which protrudes from the workbench, to catch all the sparks. It saves me a lot of sweeping time.

All in all, grinding the blade is quite simple. Don't try to rush your progress, constantly check to see where needs more, or less, grinding. Make sure everything is perfectly even and symmetrical. The plunge should line up on both sides of the blade. The thickness should be uniform throughout. When done grinding, trace the blade on paper and redesign the handle. There's a good chance some unalterable changes were made, and so the handle must be designed accordingly. The blade shape won't change from here, so make it good.

Perfect is good enough.

This is an incredibly simple blade shape, ideal for a first knife. The clean grind is half the look. A well-done grind is the most important feature aesthetically in a blade. It doesn't even take skill; just time and commitment to perfection

This is an incredibly simple blade shape, ideal for a first knife. The clean grind is half the look. A well-done grind is the most important feature aesthetically in a blade. It doesn't even take skill; just time and commitment to perfection


I'm hoping to expand the Broke Bladesmith, to things such as shop tips, handle material features, tricks, little-known methods, and more giveaways. Ideally, a podcast will accompany the broke bladesmith, interviewing other smiths, who have way more knowledge and advice than I. That's in the future however. Currently however, I'm working on a website, which should be up and running before the next issue. I'm looking for more ways to help still-learning smiths, and your feedback would be invaluable.