Here is a step-by-step review of how I sharpen a damascus steel knife blade on the belt sander. You can see pictures of the different steps as well as an explanation of how I do it. Click the arrow on the right to go to the next step.
I start by designing and drawing the blade I want to make on a piece of paper. Draw the whole thing - including the angle. I often make the same shape on my knife blades - that's why I made a template in a thin brass plate. Then I can use it again and again.
Then I transfer the drawing to the steel. I "paint" the steel with a strong alcohol marker and mark the outline with a scratch tip. That way you can always see the lines. If you draw the outline with a marker, both the heat when sanding and the water during cooling will remove the lines.
For this blade I use a piece of damasked steel from Balbach. That's why I don't cut the angle out of the steel. It is rather expensive steel and there is no reason to use it for the angle that just needs to be glued into the shaft anyway. I weld an angel on in some other steel. More on this later.
I clamp the steel so I can cut the blade out with an angle grinder. REMEMBER safety equipment. Glasses and hearing protection are a must when working with the angle grinder.
Then I cut away the redundant parts of the steel with the angle grinder. I cut as close to the lines as possible - so there is less to sand away on the belt sander.
The blade is now roughly cut out. You can still see the clear lines from the scratch tip.
Now that you're getting started, you might as well make some pieces...
Now I can weld the angel onto the blade itself. I weld it with a welding machine where there is flux in the wire. It works super well. If you use other types of steel that are not damascened, it is easiest to grind out the angle together with the rest of the blade so that it is in one piece.
When the angle is welded on, I grind away the weld so that the angle is flush with the rest of the blade. Just rough in for now.
Then it's time to sand the shape on the belt sander. I use a coarse sanding belt that can quickly remove some material. I have electronic speed control on my belt sander - so I just go as fast as possible. It does not matter that the steel becomes hot and blue in this phase. It is only after hardening and tarnishing that you have to take care.
I mark the transition to the handle with the scratch tip so that the line is completely straight.
I sand the transition to the edges.
Then the blade is rough ground all the way around. I grind the angle thinner on the surface than the knife blade itself. This will make it easier to handle the blade later.
Now I can grind the blade flat on the surfaces. I have a strong magnet that I can hold the blade with. I sand on the surface sanding area of the belt sander and I use a belt with a grain size of P120. When you buy steel, it is usually fairly straight, but is it a hand-forged blade where you have to feather glow shells etc. can you use a coarser band to start with.
The surfaces are sanded completely flat. The next step is to grind the phase.
When sharpening the chamfer on blades, you must start by marking the center line. Therefore, I paint the entire bottom of the blade with the marker as before..
There are several ways to mark up and there are special tools for it. I use a regular drill that is 0.5 mm smaller than the thickness of the blade. I place the blade on a flat surface - here it is a granite slab. And then I can drag the drill along the edge of the blade as a kind of scratch tip.
There will be a clear line in the marker. I mark up from both sides and this makes two lines appear with a small space in between. These are the lines I have to grind along when I grind the phase.
To sharpen the phase, I made a Jigg to hold the blade on. It is a piece of angle iron to which a base plate is bolted that protrudes 2 mm at the bottom. I clamp the blade to the Jig with welding pliers.
The blade is placed with its back towards the bottom of the Jig. Then I can get to grinding the phase.
Now I can grind the phase on one side. I always have the lines on the bottom of the blade to aim for. I grind the bevel with a Ø250 mm contact wheel and thus get a hollow grinding bevel. I angle the land to match the angle of the bevel and then I can grind the bevel by running the Jig with the blade back and forth on the band. I sand here with a coarse belt that can quickly remove some material.
When I have sharpened one side, I turn the blade over and sharpen the other side, I sharpen only to the lines and thus leave a small surface. I leave it as it is, as the blade must not be sharpened completely, as you risk the egg "CURLING" during hardening. You have to be very careful that the phase starts in the same place so that the egg becomes completely symmetrical. With the Jig it is actually very easy to control.
If you want to make a top phase like here, it must be done in the same way as the real phase. However, I don't grind the top phase that high.
When the phase has been sanded all the way around, I re-sand with finer and finer sanding belts. I start with P80 and end with P400. It is easiest to sharpen before hardening the blade, as you have to be more careful when the blade is hardened.