I finally got around to trying to put an edge on a Kabar since the factory edge was not very sharp. I gave it a go on the Edge Pro and noticed when I got to the belly and tip that the angle I set that matched the flat portion of the blade was much shallower than the factory edge at the tip. I tried sharpening the belly and tip at a slightly steeper angle which didn't go great. My transition area was pretty obvious and even with a steeper angle I was still doing a lot of work to try to reach the edge. I basically gave up and figured I would try it on the Lansky the next day. I still struggle with keeping the blade locked down on the Edge Pro and I know I'm not presenting the knife exactly the same way each time - not to mention my left hand sharpening of the opposite side of the blade is always shakey at best. So anyway - I locked it in on the Lansky and sharpened at 20 degrees, doing the bottom of the blade and then moving the knife in the clamp way up toward the tip to sharpen there separately, but at the same angle. With the diamond stones I eventually took the whole edge to 20 degrees per side, and it's very sharp now, but the bevel at the tip is easily 4 times wider than the bottom of the blade and started encroaching into the raised spine in the blade that strengthens the tip. I realize that my wonky reprofile of this blade is cannot be undone, but I'd love to know how I should approach the same scenario on other knives in the future. What do you guys that actually know what you're doing do?
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Help with wide bevel at tip - please
- Thread starter Wowarning
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The primary bevels need to be profiled at a set angle. The needs done from plunge to tip. Many blades are in this condition including many factory knives. If bevels aren't ground using a system where the grinding angles can be maintained this will occur. The belly of a blade is the hardest area to maintain this constant angle; its because there are so many variables. The bevels are changing along several planes, both the thickness of the blade, the rate of curvature changes when the edge hits the beginning of the spiral clear to the tip. It takes time to learn how to grind the belly of a blade and the grinder needs to be able to control the angle and keep the angle constant.
In our shop we've built a wet grinder 2 x 72 to do just this. When grinding kitchen knives this is especially critical since the blades are so thin and must have a refined grind the entire length of the edge. A kitchen knife with a thick belly is useless in the kitchen.
Regards, Fred
In our shop we've built a wet grinder 2 x 72 to do just this. When grinding kitchen knives this is especially critical since the blades are so thin and must have a refined grind the entire length of the edge. A kitchen knife with a thick belly is useless in the kitchen.
Regards, Fred
Putting sharpie marker on the edge of the blade, and even some up on the body of the blade is a great way to see where your stone is hitting the blade as you grind. I spent years thinking that the sharpie technique was "just for beginners" and I wasn't a beginner right? I'd been doing this for YEARS. Bzzzzztt. Go to the back of the class. The sharpie technique is invaluable. I use it rather frequently. I reapply when I want to get another clear look at where I'm touching the blade.
Do a little work. Look at what you did. Adjust. Do a little work. Look at what you did. Adjust. Feedback loop. The key to great results.
Brian.
Do a little work. Look at what you did. Adjust. Do a little work. Look at what you did. Adjust. Feedback loop. The key to great results.
Brian.
Thanks guys. I do use the sharpie all the time. It wasn't really a question of not knowing where the stone was hitting - it was an issue with keeping a constant angle through the belly and tip resulting in a very wide bevel in that area. I can totally see where using a belt or freehanding on a stone would allow a smooth continuous adjustment to the angle, maybe that is the only way to pull off this type of knife. I was really curious if anyone else with a fixed angle sharpener had a method that worked well. I think Ben said something in one of the videos about the bevel widening at the tip because the blade is thicker there. I thought the USMC was going to be a breeze to sharpen - holy moley was I wrong, lol.
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Yeah the USMC is a PAIN hehe, and on that particular blade, the tip does indeed get very wide. That's the nice thing about the Wicked Edge is that you actually can do the continuous adjustment to go from a shallower angle at the heel of the blade to a steeper angle at the tip to help make the bevel look even, even though the blade gets thicker at the tip. Unfortunately I don't see how you can do that on the Edge Pro. Your other option is to regrind the primary grind; as Fred pointed out above they did not keep the primary grind consistent in the factory. Here are a few pics of what I mean and how your issue can be fixed:
Here is a pic of a similar model USMC Kabar that turned out great... see the nice thin edge now that is super easy to sharpen and touch up, even on a sharpmaker?:
Here is a pic of a similar model USMC Kabar that turned out great... see the nice thin edge now that is super easy to sharpen and touch up, even on a sharpmaker?:
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Adjusting the angle of the devise being used to sharpen a blade in order to match a poorly ground bevel is giving credence to a poorly ground blade. The end result is a blade that looks correct in its geometry when in fact the blades edge is ground incorrectly. What you have in hand is a blade with different cutting abilities depending on where you are working along the cutting edge. This is one reason I stay clear of blades with convex ground primary bevels. Using this technique allows the maker to cover up many grinding abnormalities only to be discovered by the final user/owner of the knife as in the case of the OP's knife.
Fred
Fred
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Thanks guys. I have not done a video on this specifically guys, but basically it depends on how you tip the knife in the vise. I can get the angle to increase significantly near the tip using this method or I can make it widen up. All depends on what I am wanting to do. For example, on most ZT's the bevel must get steeper at the tip or it will widen up significantly. You could probably force this on the EP if you knew what you were doing.
I agree w/ you Fred, however, it is not always a bad thing, as in this case. In this example I purposely made the tip widen up a bit so that way prying would be in no danger of snapping the tip. It depends on what the end use is... if it's a purpose driven design that needs to have very strong prying ability then it could be beneficial. But typically it is as you say, accidental due to poor grinding technique. The same applies when sharpening a knife on the secondary bevel, if you keep the spine of the knife parallel to the floor you actually have to alter the grind by bringing the spine in toward the belt as you get closer to the tip - if you want the same edge angle. If not then you can do as most do and simply pull the handle back away from the belt.
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As mentioned by others great looking re-grinds. Its an art in my judgment.
I agree the geometry must be use driven if you want to end up with a tool that is applicable to the job. I've been grinding blades for 17 years and the knives I build today look nothing like what I made ten years ago. Ten years ago I was driven by the "look" of the knife with the cutting ability being a secondary consideration. Today I build from the edge back to the spine, selecting the correct thickness of material, type of steel, primary bevel angle, distal taper and finally the sharpening angle of the actual cutting edge. The heat treating is of course a primary consideration.
Since I use the Bubble Jig with set angles to control all angle surfaces of a blade there is no way for me not, to design from the edge back. I've found knife making to be one of the most interesting learning experiences of my life.
Do you have videos of your re-grind techniques? I'd like to see how you attain those extremely clean grinds.
Regards, Fred
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Me too!
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No I don't but I'll try to get one up sometime soon =) It's done freehand... once in a while I do mess one up but I always replace it if I do. That's why I set my limit at $500 per knife that I am willing to regrind. But most of the time there are no issues and they turn out nice! Biggest set back to me currently is my grinder... I'm using a NWG that I built (2x72) on a pulley system. Getting ready to probably pull the trigger on a TW90 though.