Advanced Knife Sharpening Series: Zero Grind Edges Using Diamond Belts on M390
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- เผยแพร่เมื่อ 7 ก.ย. 2024
- In this video I demonstrate converting a flat grind bevel to a zero grind. I'm using a Coote Belt Grinder with a variable speed motor and a forward and revers footpedal. This setup is described in more detail in a previous video.
First I review various regions of the belt - the top pulley, the lower 10" contact wheel, the platen and the slack portion of the belt. I focus on the region to either side of the platen and demonstrate how these various regions have differing degrees of flexibility from the middle of the slack area to the area to either side of the pulley.
The knife used for this demonstration is the Richmond Artifex. This knife uses a very abrasion resistant steel, M390.
While the original angle on the knife is quite reasonable, I'm a bit more extreme in terms of putting ultra high performance edges on knives, so I'm going to convert this edge to a zero grind edge. What this means is that the two sides of the knife will be meeting with no separate bevel and only a slight convex grind on the edge of the knife.
Please note that this sort of a grind is not easy or even possible to make with a poor quality steel. As you will see in this demo, this knife has absolutely NO problem taking this acute of an edge, showing itself to be a remarkable steel and heat treatment!!
To perform this tasks, I'm going to be using diamond belts, which work remarkably well on these abrasion resistant steels.
The material that these belts are made of I also have available mounted on glass for the EdgePro, 1x6" 2x6" Wicked Edge to fit the standard paddles and as bench strops in 3x8" size to fit standard stone holders. Please note that I am not using water cooling in this video and at the speeds I am using generating almost no heat buildup as these belts run very cool. When using these belts as bench 'stones' or strops, I do use water as one would with diamond lapping plates or waterstones.
The first belt is a 125 micron belt - approximately 120 grit. I run the grinder at approximately 1000 RPM.
Using my leather gloved hand as a platen for support in the slack portion of the belt I begin grinding away the bevel, including the area behind the bevel. This is essentially thinning the knife and knife edge until no bevel remains with a slight concavity imparted by the 'give' in my hand being used for support to produce a convex edge. I continue, taking advantage of the area immediately in front of the platen to grind a more acute convex bevel. I repeat this procedure on the opposite side. Note especially near the tip how long I can remain in contact with the blade without overheating the blade which stays cool throughout the procedure.
The diamond belts cut through the M390 'like'butter' with little more effort than more ordinary abrasion resistant steels.
Next I switch to a 74 micron belt to refine the edge and work on the entire surface with this belt, avoiding the logo using the technique mentioned in an earlier video.
I develop some burr with this belt and demonstrate deburring by abrading it off using LIGHT pressure. Note the sound decreased using lighter pressure.
Next I go to 45 micron belt, continuing to refine the edge. The knife will be further refined to 9 microns on the grinder and finished using hand sharpening techniques.
The M390 Artifex is available at Chefknivestogo. For more information about the diamond film products including bench strops or plates and films mounted for use on both the EdgePro and Wicked Edge, contact me directly.
Excellent tutorial. Many thanks.
Thank you!!
Zack, you are correct. Extreme care is required.
at Ondrej Consider linen belts with CBN or diamond on it. Far more affordable and longer lasting than diamond belts. Trizacts come in aluminum oxide but there is a limited amount of silicon carbide and diamond trizact available. Diamond trizacts are VERY expensive
Best video I watched today 🔪✨
Thanks!!
Great video Ken!
Nice job ken!!
Thank you!
This is but the first step. The edge gets further refined, the sides cleaned up and then it will be hand sharpened and stropped to typically a 160,000 grit edge using tenth micron CBN or Polycrystalline diamond. Pricing depends on the knife, it's condition, etc. Send me email for details ksskss earthlink net. Bob, thanks for commenting and watching the video.
How can you tell if you are putting too much heat into the blade while you are wearing gloves?
Ken, thank you. I am starting with a Harbor Freight 1 x 30. Question 1: edge facing on coming grit vs. edge facing away? Coot set-up looks very high end for beginner like me. Just want to resharpen families knives blades with 'practical edge'. Question 2: succession of grits (e.g. 400, to 600, to 800, or higher 1-2-3K+ (AlO/Si Carbide) or micon 125-75-45 Diamond) Question 3: Use white or green compound on leather (polished vs. soft side leather). Other's mention your liquid micron (presume diamond) abrasives, when do we use these, sort of pricey. Notebene; use small (HF) magnets in corners of grinder to collect metal debitage. Also, cut strips of synthetic (kitchen) sponges, hold on blades to act as a heat sink Make incomplete cut/slit on long edge to 'hook over top of blade. Could send you a drawing on how I cut them. Learning this skill...I am smart in other stuff and know I ask to many questions. Do you ever have or host hands-on workshops? I can bring all my equipment. Oh by the way (on-off only) foot interrupter switch available at HF. Also, have had blade facing into oncoming grit 'catch' cut belt and flip dangerously \. Following you have subscribed Very respectfully Dr. TG Cloonan Col(ret) Surprise AZ
Timothy Cloonsn, give me a call 209 612 2790 and I can give a full explanation
You can really hear the difference in the different grit belts. Great video
If you look into what they use on "stroke sanders" you'll save on gloves - it's a graphite impregnated canvas material that is made for pressing on the back side of a sanding belt. And it's much slipperier that a leather glove thus generating less heat. You could glue some pieces to the fingers of your gloves. May sound kludgey but I think it would work great. www.supergrit.com/products/products_accessories-graphite www.sandpaper.com/products/accessories/default.asp
Good idea! I have used this material on a platen - works well. Thanks!
I bought my Coote in 1998 and you add your own motor. It's great for sharpening but not heavy enough compared to the KMG or the Bader.
Danvil Perhaps. Knock wood mine has been going strong for msny years. Check out the tw-90 by Travis Wertz if you want to spoil yourself
Goro,
I make Atoma diamond plates for the WEPS. The first question would be if you are keeping existing angles or making them more acute. For reprofiling, I'd recommend a 140 Atoma pair for the WEPS. For initial grinding on the belt, a 125 micron diamond belt is nice not cheap. Otherwise consider structured ceramic abrasive belts for initial bevel setting. Contact me for more details.
I cant however see why in this particular scenario why it wouldn't be ok with the belt going away from the edge?
Mike Sloan Mike it is commonly done this way. I dont do it this way on leather belts however. Try it. You will be surprised.
Thanks for the tutorial. I've been sharpening with a delta belt grinder and getting nice, sharp knives, but wanting to get rid of the micro bevels for a zero-convex grind. It appears you're pretty much laying the blade flat on the belt? 1) Why do you grind with the belt moving towards the edge? 2) What do you do about the scratches from the belt touching the sides of the knife? 3) When you grind to such an acute angle on an already thin knife, does it make the edge too weak? Thanks again...
So to resharpen without getting a second bevel you do the whole knife? Looks very pretty aesthetically I guess.
ken, great video. I'm a bit curious about nubatama knives, on CKTG the description says that they are made of "black steel". Could you talk a bit about this steel, how different it is from, lets say, white #1?
Thanks Ken, as always I learn something from your videos, if you don't mind me asking; what would you charge to do that zero grind?
Great video! Quick question... Have you ever tried sanding belts from Maverick Abrasives? I recently switched over to them from 3M & they have been performing significantly better...and their pricing was 20% better, believe it or not . THought i'd pass along the info :) And they also manufacture buffing wheels & buffing compound!
How do you deal with the scratches behind the edge sr?
You go through a series of finer and finer belts and then switch yo cbn linen belts up to 0.1 microns or 160,000 grit
kenneths123 Thanks 👍
kenneths123 Doesn't it take longer to get rid of the Scratches, than the Sharpening the knife? Thanks for sharing and for your time Sr.
@@Crazyknives Yes it takes longer. You are working much more metal.
kenneths123 how can I buy diamond belts from you? Thanks
Loved the video. Educational, mostly for pros...
Where do you shop for best priced Diamond belts?
Thanks for the posting.
+ronin4711 You can get them from me. Contact me at ksskss earthlink net .
My new custom knife will be here next week. It´s a 4 inch fixed blade from K390@64-65 Rockwell. I already have an Elmax (similar to M390) custom knife but I expect K390 to be much more wear resistant. I have WEPS and also slow speed belt sander with Trizact belts. Do you think these belts will be enough for a K390 blade? Or should I buy diamond/CBN belts? Are they worth the price? And what speed do you recommend for diamond belts? More or less than 10 m/s?
Hello, I wanted to know if this steel is really excellent as they say? In your opinion is the best on the market for steel knives with fixed blade? It is difficult to sharpen? Let me know what you think, thanks to Michael.
This is a somewhat abrasion resistant steel. There is no perfect steel and even for a given steel, heat treatment is very important. With the correct abrasives, it is not too difficult to sharpen at all. With poorer quality stones or stones of the wrong type you can suffer.
1)How do you keep the convex geometry when finishing with hand technique? On a flat stone? 2) How do you decide whether to have the belt moving toward or away from the knife's edge? Isn't it more likely to pit the edge with the belt moving toward its edge? 3) what were the other micron sizes in the abrasive progression? 4) Is there a quick reference for the steel types for various knives, or must we research each one? Thank you.
c62west dont you love when you dont get a response?
Ken, technique for re-sharpening utility blade knives? grit progression, positioning on belt (cross-wise or longitudinally) how to secure. Sincee with questions, Very Respectfully, Col C
Timothy Cloonsn, give me a call 209 612 2790 and I can give a full explanation
I have owned a coote for 15 years and it is one of my most used grinders and I run three grinders.enjoyed your videos and I like how you have the grinder set up.you have the gusy contact info or web page where you got the motor and control.check out some of my knife makeing videos.keep up cool videos
Houseknives Contact Edward Frye at Electric motors wholesale for more details. Thanks for the comments.
How do you keep the edge centered? Just by feel and timing. Do you check after each belt and center with a lighter grit?
Daceyhaughwout I check after each pass. if you mauntain a constant angle, you eliminate a major portion of your variability
If its convex it wouldnt really be a Zero grind like a Scandinavian grind. Why not use the flat part over the metal plate for getting it truly flat?
Thank you! I'm glad you enjoyed the video.
Regarding Nubatama knives, please contact me at ksskss earthlink net and I can go into a good bit of detail about black steel.
Its like convex sharpening in the 5 to 10 degree range essentially
Yes, pretty much so depending on the thickness of the blade.
i don't dare to grind a knife on my belt grinder with the sharp edge facing the belt direction once it's sharp, fearing that it'll grab the knife and fling it towards me, or worse... is that unfounded? nice video, thanks for the effort.
MOST belt grinders go in an edge leading direction. I know it sounds scary, but after the first couple years, I didn't do edge leading but now I'do both without problems. No problem at all with regular belts. Be careful with linen and leather and felt belts - strops. These WILL bite and you cut the belt. Heavy belts likle say a blaze belt - you would be pretty much impossible to cut them. Give it a try - really not that scary aty all.
kenneths123 i have built my own EERF grinder with a 2hp engine and a frequency regulator. the machine works like a charm, especially after i upgraded the platen with proper wheels and bearings and never had any problems with it. come to think of it, a belt snapped on me once while i was pushing a knife spine up against the belt direction...
thanks for your time, i will try it.
thanks for the video as a 'returning' knife maker and sharpener I am interested in learning all I can, I found your video informative and interesting.One question do you always use your belt sander in the horizontal position? thx for sharing mate
I usually have the grinder at a bit of an angle past horizontal rough;y 10-15 degrees typically
at None None A scandi grind is flat on both sides much like a single bevel front side of the knife. A zero grind is slightly convex at the most acute angle possible on a double bevel knife. For a scandi grind you would use the metal platen for backing.
kenneths123 What size is this sander, on the Coote website they have a few different models.
***** This is the 2x72" unit with the 10 inch contact wheel
No, a zero grind is not convex in any sense of the word. It is perfectly flat. The ONLY two zero grinds are the flat grind, and the Scandi grind.
Actually not. Zero grind simply refers to the two sides of the blade meeting with zero primary grind, ie no separate edge bevel. It can be a flat or Scandi grind but it is not that restrictive. There are many examples of zero grind blades that Japanese and American knifemakers use and I refer to zero grinds in this context. If you have another context, we can simply agree to disagree.
Timothy Cloonsn, give me a call 209 612 2790 and I can give a full explanation
So you consider this advanced??!? Even beginners won't make that kind of stupid mistake @ 5:51 ROFLMFAO.
psy Amok Show us your finest work. Love to learn from your wealth of knowledge