Newb DLF question
- This topic has 24 replies, 6 voices, and was last updated 11/24/2018 at 3:22 pm by
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Aaron, break the knife down and work your strokes in smaller sections. Maybe do your knife in two or three portions. It should be easier to correct your technique by working on a smaller portion of the blade. Then overlap the portions to blend then together. Do it this way for any stroke direction you employ until you get comfortable with the motion and then you can refine your technique.
Concentrate on holding the stone paddles flat against the bevel. Try to keep the stone in contact with the entire height of the bevel from the shoulder of the bevel to the knife edge of the bevel, where ever the stone is in contact with the bevel. Maintain this constant contact with the entire bevel as you move the stone down and in, or up and off, as you move the stone from heel to tip, or from tip to heel. You’re trying to maintain a full flat contact patch between everywhere the stone paddle contacts the bevel without any rocking motion or loss of contact. While sliding the stone paddle up or down the guide rods as you rotate or swivel forward from the knife heel to the tip or backward from tip to heel. This constant contact is the secret to success.
Try to visual what your trying to do. Concentrate on maintaining the sideways flat pressure between the flat stone paddle and the flat bevel. Like I said, maybe work or concentrate your efforts on smaller length portions of the bevel. I believe it’s a misconception that the stones motion and pressure is down and onto the knife edge, or up and off, like your whittling or scraping off the steel to thin the knife into a pointed shape. But in reality your grinding or sanding the two opposite side bevels flat as you thin the knife edge. As you remove the slightest of layers of the flat sides they get closer together and flatter at the line of intersection between the two bevel sides. This line of intersection is the knife edge. The more precisely the bevels intersect to make this finer line the sharper the knife edge will be.
Visualize and concentrate trying to feel this constant flat contact as you slide the stones across the bevel in the direction of the stroke you choose to utilize. Use your sense of sound, listening for a sound change as it sounds scratchy as you’re losing contact and the contact patch changes. You’ll become accustomed to the flat feel with the sideway pressure and the sound ssociated with it.
This same flat contact technique is used with each and every direction stroke. By alternating the directions with each grit change in the progression it helps keep track of your sharpening progress.
I finish off each grit with several alternating, left-right-left-right strokes with the heel to tip edge leading stroke direction, to insure I have knocked off any remaining burr I may have created with that grit I’m finishing with, now. Then I move on.
Each successive grit is done the same way with the same flat contact on the bevel. Consistent repeated technique and attention to detail through the entire grit progression is what gives sharp and polished edges.
Just to summarize: the motion of the stone is to slide it up or slide it down the guide rod while it’s rotated around the ball joint swivel from the knife heel to tip or from the knife tip to heel. All the while the stone is being moved and rotated along the guide rod I apply very light sideways pressure to maintain light complete flat parallel contact between anyplace the stone and knife bevel meet. This contact patch moves along the knife edge and the stone, concurrently, as the stone is moved through it’s range of motion along the knife edge and the guide rods, simultaneously. The remnant scratch pattern on the bevel is in alignment with the stone’s motion across the bevel.
Marc
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I want to emphasize what Marc said above about light pressure, especially when you’re finishing the edge with the last stone. Using just the weight of the stones themselves or even holding a little of that weight back from the knife in the final strokes makes a significant difference in the resulting sharpness.
-Clay
Jacob, it can be misleading using the sharpie. IMO it’s a good guiding tool to get you in the ball park. Unless you view the knife edge under magnification it may appear your removing the sharpie at the knife edge while really your not quite there. You’re really not apexing the edge.
Several things will prevent the sharp edge your used to. First if you not reaching the edge with your bevel work on one side, the other side or both sides. Then you haven’t brought the two knife sides together precisely at the apex. Finally you have to put enough time and effort to bring the two bevels sides together precisely and completely down the full length of the knife edge.
That precise intersection of the flat planes you’re making with the stones, that is the bevels your making on either side of the knife. Where these planes intersect forms a line. This line is the knife edge. The finer, the straighter and the more precise the intersection of these planes to form this line, the knife edge, the sharper the knife the will be. If your doing all these things and your knife isn’t sharp then it suggests your technique needs improvement or you haven’t worked each step in your stone progression long enough or well enough with enough attention to detail. Which is another way of saying the same thing: your technique needs improvement. Maybe you need to check your guide rod angle setting with each and every grit change to insure your working at the same angle setting for each stone. Concentrate on keeping your bevels straight and flat. Finish each stone’s work with side alternating, (left-right-left-right) edge leading strokes, ( i.e., down and onto the knife edge), to be sure your removing any remnant burr. Before you moving on to the next grit.
Even, if you are somewhat off in your knife clamping position, for this resharpen job, compared to the first position you clamped it at, when it was originally sharpened. If you utilize proper technique every stone step of the way the knife edge will be reprofiled to this current clamping position and it will get sharp.
Technique, time, effort and attention to detail. Go back to the basics.
Marc
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Jacob,
Did the knife feel sharp after the 600 grit stone? I like to test the sharpness as I progress through the grits by using phone book paper. This is convenient because you don’t have to remove the knife from the clamp in order to test the edge. Once you have raised a burr on both sides and then cleaned it up with alternating strokes the knife should be sharp.
I suspect that you are either not quite reaching the apex with the 800 and 1000 or your stropping technique needs work. It took me some time to figure out how to get good results from the strops. It seemed like they were dulling my edge rather than helping. What eventually worked for me was to drop the angle by 1.5 degrees per side like you have been doing and then to use firm pressure.
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Jacob, what we can share with you is what we do, that is what techniques and methods we employ, as a suggestion or guideline for you to try. It doesn’t mean that it will necessarily work as well for you as it does for those of us making the suggestions. Each of our styles and technique nuances may be just different enough to give that difference between the sharpest knife you’ve ever achieved and “hair whittling sharp”.
It reads like you are certainly on your way. Remember, it takes time and practice, so be patient. Your attention to detail and technique is paying off for you. I personally do not know if every knife or every steel is capable of being sharpened to hair whittling sharpness. That being said, I’d do everything the same for a couple more knives, with the same, or even more, attention to detail and see if your results might improve. If you still don’t get the edge you’re seeking, you may just need to tweak it a little by trying things like changing up your stropping progression or maybe the stropping angle reduction or the pressure you utilize. Only make one subtle change at a time. Then apply that change to the next knife you sharpen. See if it responds with a better outcome for you. Do this till you get it dialed in, with slow incremental tweaks
Also you may want to try the hair test prior to stropping. Stropping, in my opinion, smooths and refines the edge. The stropped edge has less of that slight roughness, and possibly has lost the “wire edge” sharpness. For the paper slice test, the stropped edge feels smoother because it doesn’t grab or catch the paper because you’ve removed that roughness with the stropping. We equate this smoothness and less cutting resistance as being a sharper edge. But, this same roughness we remove with stropping may be just enough to grab a hair and “whittle” it.
For a working edge, such as my kitchen knives, I only do a two step strop; 4µ, then 2µ. I consider using multi step strop progressions when I’m looking for a mirror reflective “show-off” edge.
Marc
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I don’t know if it is possible to strop too much when done properly. I sharpened a knife yesterday that came out hair whittling sharp and I used a full progression of strops: 14, 10, 4, 2, 1, and 0.5 micron. The edge cleanly cuts hairs with the hanging hair test and can also whittle hair as well.
The edge geometry might be important for this cutting task. The edge was 12 degrees per side and is very thin behind the edge on this particular knife.
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