Sharpening knives with a Tormek
Date Posted:30 September 2015
Our friends at Tormek put out a video showcasing their two popular knife jigs.
Below is the transcript.
In this session of our Tormek instructional video series, let's sharpen some knives. Now a lot of folks that own the Tormek or if they are thinking about getting a Tormek, ask me why we have two knife jigs when to use one and when to use the other. The S V M forty five regular knife jig can handle a knife of any length up to fourteen inches as long as the blade is relatively stiff like the chef's knife. The SVN 100 Long Knife jig is designed for blades that are not just long but long and flexible like this fillet knife. Other than the extra clamping support of the SVN100, the two jigs are identical and work exactly the same.
Today we're going to be using the SVM45 on this thirteen inch chef's knife. To start we're going to take the knife and put it into the knife jig with the cutting edge of the knife and the front edge of the jig approximately parallel with each other. We're going to use the small knob first to clamp it and then the large knob gives you a leverage effect that gives you a very secure grip on that blade. This section of the knife jig is called the head and the head is going to rest against the universal tool support to give us the proper grinding angle. Now for kitchen knives, hunting knife, pocket knives pretty much everything except carving knives and fillet knives, we want to grind a forty degree beveling on that blade. Now remember on a knife, we're grinding both sides. So a forty degree bevel angle is really two twenty degree bevel angle. the steel is also very thin right at the cutting edge. So measuring that forty degree angle would be very difficult. What we're going to do instead, is measure each side, which is twenty degrees. We can measure that directly to the body of the blade. It's much easier to see what we're doing.
So we'll take our set up gauge called the angle master. We're going to put the pointer on twenty degrees the other side is adjusted to the diameter of the grindstone in this case two hundred forty five millimeters. Then we're going to put the head of the knife jig on the universal tool supports and the blade of the knife on to the stone and check our angle. We're going to get in the neighborhood by adjusting the height of the universal tool support. Made much easier now that we have the micro adjust bar. When we get close, the head of the knife jig is threaded which becomes a micro adjuster making it very easy to dial in an exact fit. And there's a lock to make sure the jig stays secured once you find your point.
Now if you saw Norm build this stand on the New Yankee Workshop, you know that has a pull out step which is very nice for tools like knives where you'd like to be above your work looking down on what's going on. So we're going to start the machine. One thing we want to talk about here is using the stone grader. When you're sharpening knives on the Tormec, very seldom are you going to be the faster cutting action of 220 grit. For the most part, you want to use the one thousand grit cut only. So we're going to use our stone grader and polish the surface of the stone down to the one thousand grit cut before we get started. Now if you have a knife that is very badly beat up, lots of nicks, it's been used for the wrong things go ahead and use the faster cutting action for a few moments to get the majority of the nicks out and then go to your one thousand great cut. But for maintenance, the one thousand grit cut is all you'll need for most knives. Put the head of the knife on to the universal tool support and begin grinding. Now as we come to the curve of the blade, I'm gonna follow that curve by picking up on the handle of the knife. The best thing to do here is to watch the water flow as it comes up onto your knife. As long as the water is flowing over the majority of the edge you should be in pretty good shape as far as alignment to the grindstone. Two or three passes on that side now we're going to turn it over. We don't have to reset the jig, we don't have to take the knife out and turn it over. Just turn the whole thing over and there's exactly the same bevel angle for the other side of your blade. It's a perfect mirror image of itself. So you know you're going to have the same bevel on both sides.
One thing I'd like to point out here is following the bevel to make sure that we have a consistent bevel all the way around the blade. A lot of folks look at the one they see the radius here on the corner and decide that that's how you want to follow the curve of the blade, is by going this way, and that's going to mess up your belt. What you want to do is go this way. OK so to do this again one more time so you can see what's going on. We're going to follow that curve by picking up on the handle of the knife. One more pass on the other side. And we have our blade. Now we're going to take it out of the jig. I'm going to turn the Tormek around. Put a little bit a honing compound on our leather wheel. And now we're going to polish that edge out to a mirror finish up. This is going to remove the wire edge and refine the scratch pattern in the steel. The finer that edge is, the finer the scratch pattern on the edge is, the longer the edge is going to last. Now this is not a difficult thing to do even though you see we're not using any of our control systems. Basically you just want to get that bevel on the leather and you'll also notice I'm working at a skew angle relative to the leather that so I don't run into the grindstone. It also makes it a bit easier to feel the bevel on the leather. A few times going back and forth. Wipe off any residue.
And now a question comes up from time to time, how do you test that edge?. How do you know whether that air just truly sharp or not? Let me give you a couple of methods. One is to take a piece of paper and you may have seen me do this on the chisel demonstration to and if you can slice through that paper with absolute control without the knife catching or grabbing or tearing the paper, you got a good sharp edge. Another way to test it is with your thumb nail. If you can rest the blade on your thumb nail and it catches your edge is sharp. If it slides it's not sharp. Now you're not supposed to cut your thumb nail, you're supposed to rest it on there and see if it catches. If it slides, you're not there yet. If it just catches, you know you've got a perfect cutting edge which we certainly do on this night. Thanks for watching we're going to have demonstrations on our other jigs as well. Be sure to catch them all.