Sharpening My First Knife at Sharpening Supplies
It probably comes as no surprise that as part of my job training, my boss wanted me to find a dull knife and sharpen it. This task would be made more difficult by the fact that my boss and other sharpening specialists in the shop have easy access to devices that can 'measure my performance'. Not only would I be evaluated on whether I could sharpen a knife, but also on the degree of sharpness. My first job would be to find a good candidate of a 'dull' knife.
As it turns out, I was visiting my parents over the weekend and found out that they had an entire set of dull, vintage wooden-handled Chicago Cutlery knives that would be perfect for my task. A few decades ago, it seemed like every family had a set of similar Chicago Cutlery knives. They were considered good knives at the time, but more recently, those same sets of vintage Chicago Cutlery knives are often found dull in a kitchen drawer after years, if not decades, of use/misuse.
I brought in this set of knives to show my co-workers. The almost universal disgust over the dullness of the knives was a bit intimidating. I thought for a moment that maybe I had made a mistake. Did I choose a knife that was too dull? Were these knives good enough to actually sharpen to a fine edge? Did my co-workers know something I didn’t know?
I selected the Chicago Cutlery 61S to sharpen. It was a good size to sharpen and best of all, it was not only dull, it was very dull. But, before I set off to sharpen, I needed to evaluate the edge.
Evaluating the Initial Sharpness of my Chicago Cutlery 61S
There is no question this knife is dull. This knife wouldn’t scare a peeled grape. But I wasn’t just here to generally state that it was dull, I needed to measure it quantitatively. That meant getting out the Edge-On-Up Edge Tester. This little machine measures the amount of force it takes for the knife to cut test media and gives you a number in grams. The higher the number, the duller the knife. I took 5 measurements along the edge. The results had my co-workers laughing.
Here is a chart of the test results. For comparison, a brand-new knife is about 250 to 350 while a butter knife is about 2000. Well, I think the results speak for themselves, this one was DULL!
Based on the reactions of my co-workers, I was really doubting my decision to sharpen this knife. But there was no turning back now. I had to dig in, get my hands dirty and sharpen the knife.
Sharpening The Knife
I decided to select a 15-degree angle to sharpen my knife. I had my co-workers evaluating me so I wanted an angle that would give me a good chance at achieving a very sharp edge. That lower angle would help give a sharper edge.
Since I knew it was dull, I knew I needed to start with a very coarse stone, or I’d be spending the whole day just establishing a new angle. Fortunately for me, whoever tried to sharpen this before, (probably decades ago) sharpened it to a very low angle. This low angle made my job easier since I had to remove less material from the knife.
I started with the DMT Extra Coarse Duo-Sharp Plus (220 grit). In my experience, this stone works very well for establishing an edge. In this case, the stone was able to cut through the steel with relative ease. Without too much effort, I had sharpened both sides evenly and had felt a burr, so I knew I was ready to move on.
I next took the blade to the other side of the stone, in this case, the coarse side (325 grit). This grit really started to restore my hopes that this knife could still be salvaged. The purpose of the coarse grit, was really to prepare the edge for the finer grits. The Extra Coarse left a rather rough surface that is much more easily refined on the 325 grit of the coarse stone.
The next stone I used, was the Fine grit on the DMT Duo-Sharp Plus (600 grit). After using the Fine grit, the edge finally began to look like something that was really ready for use. In some cases, this is the finest grit stone that people own and it can work well in the kitchen. However, I wasn’t after just a workable edge, I needed a really fine edge.
I then flipped over my stone and used the Extra Fine side of the same DMT Duo-Sharp Plus (1200 grit). After using this grit, the edge started to take on a shine that is often indicative of a sharp edge. I knew I was getting close.
During my training, I have really appreciated water stones for polishing the edges. I then went to a 3000 grit Naniwa S2 Super Stone. This stone feels smooth and only slightly abrasive. However, once I was done, I could see that the edge was starting to shine.
The next stone I used was a 5000 grit Naniwa Professional Stone. It wasn’t necessary to switch to a different series of stone, but I had it handy and wanted to see how it differed from the Naniwa Super Stone. My co-worker, Dan, said that the Professional Stones will cut faster than a comparable Naniwa Super Stone. In this case, it added a little polish to the knife very quickly.
My last sharpening stone was the 8000 grit Naniwa S2 Super Stone. This is a very common 'finishing' stone, so I wanted to finish sharpening on it. The stone feels very smooth, so smooth that there is no perceivable abrasive. At this point, my knife was very sharp. I tested it by slicing a piece of paper and it cut very cleanly. I was thrilled that I was able to pass this test, so I knew I was on track.
Not wanting to stop there, I decided to take it to a strop. I used our 12” Double Sided Paddle Strop. Early on, I realized that this is a little secret to super sharp edges. I first used the suede side with some Green Honing Compound. Then I made a number of passes on the smooth side without any compound. I was ready to be evaluated.
I probably didn’t have to use every single grit I used. I could have probably used just two water stones and achieved the same results. But I had access to all the stones so that is why I used so many grits. It wasn’t my intent to give instructions to show exactly what stones to use, but rather, I was using stones I liked and had access to in the shop. I feel I could have duplicated the results with other stones we had in the shop, as well.
One challenge I did encounter was the slight concave portion on the heel of the knife. This was caused by the poor prior sharpening job, or possibly from using a pull-through sharpener that couldn't sharpen the heel of the knife. Using a flat stone made it difficult to sharpen the concave portion of the knife.
Evaluating The Sharpness of My Newly Sharpened Knife
I felt confident, but still had apprehension when testing my knife. My co-workers were present. If I took the time to sharpen a knife, only to have it fail, I’d have to face my co-workers knowing I didn’t quite measure up. My initial concerns about the knife itself were still in the back of my mind. Maybe the people that say that the old Chicago Cutlery knives couldn’t be sharpened like modern knives were right. If that is the case, maybe I really did a good job and it was the knife’s fault.
The very first time I cut the test media, my fears were removed. I had, in fact, made the knife very sharp, sharper than most modern kitchen knives straight from the factory. I had turned this beat up knife that had sat in a kitchen drawer for decades into something that was sharper than almost every brand-new knife. Neglecting the comparison to any other knife, this knife can only be described as very sharp.
From the chart below, you can see why I was so happy with my results. In the 5 tests, I achieved a sub 200 sharpness on the entire blade. In the middle, it tested as low (low is good) as 125. Given that I was freehand sharpening and had trouble with the heel of the knife due to the irregular concave sharp, I consider this to be a great success. The tip of the blade is the hardest to sharpen so I was not surprised to see that it wasn’t as sharp as the middle of the knife. My measurement at the tip was 189, which is still quite sharp.
What I Learned
The first thing I learned is that you can sharpen a very dull knife and make it finer than even brand new expensive cutlery. This was eye-opening since the knife I sharpened was a common example of the kind of knife that someone might find dull in their kitchen drawer. The second lesson I learned is that sharpening, even with my not yet perfected technique, can still get great results. As I learn more, I expect to see even better results.
A 15-degree angle is considered a fairly low angle for this type of knife. In reality, using my freehand technique, the angle was probably a little closer to a 17-degree average. Under closer evaluation by my coworkers, I had varied my angles between 15 and 20 degrees, thus creating an unintentional but still very useful convex edge. I will be using it and reporting back to see how the edge holds up. Conventional wisdom suggests that this steel could be too soft to hold up and it should be sharpened at 20 degrees, but conventional wisdom also suggests that I shouldn't have been able to sharpen this blade to be quite this sharp,.... but I did.