(“ I’ve seen some of your other posts on your M2 steel knives. How do you grind the blanks to profile them?“)
@Travis
That is a good question !
The first ones I made , I did by hand. A very slow process,
Diamond stones , long winter days ,
the patients of a drunken monk.
Not recommended. Could take ALL Day. ,! Or more!
This year , I fitted a grinding stone into a very low speed drill press.
Holding the raw steel with bare hands to feel if it’s getting too hot.
I would make a pass , dip in water to cool .
Make another pass . Making sure it never got too hot.
Never letting it turn blue from the heat of grinding.
Still could take 2 hours + on that drill press stone to profile a steel blank .
This stuff is like 65 ++ HRC. Very hard, very resistant to wear…
ie . Grinding . Just brutal to work.
There is some controversy as to if getting it Too hot grinding will damage the hardness, high speed M2 steel is called High speed because it retains most of its hardness even when red hot. High speed cutting of other steel
But one knife I made on a grinding wheel that turned blue from the heat of grinding chipped when put to use.
So I never get it hotter than I can hold bare handed.
I really wish I had a water cooled low speed grinder .
Once profiled by grinding , I go through the grits of sandpaper ,etc 250 , 600; 1000,2000, strop.
Truth is ,I have 6 or so perfect ones I have made , only need one or two. ( no they are not for sale )
But for some reason I am obsessed with this steel and make more
When I get snowed in here.
Hyde high speed M2 mill blades , my steel of choice.
Several posts on here about my knives .
The beauty of this steel is the very keen sharp edge that can be achieved. More so than any other knive “I “ have seen.
And most importantly it’s resistance to wear.
Once you get it sharp , it stays sharp for longer than most steels .
For a single bevel grafting knife i would stay in the 20-40 degree range.
This also depends on the type of steel, and how it is treated (hardended temperered etc)
Lower angles give better edge retention. However they make the knife more susceptible to chipping (smal parts braking of the cutting edge)
And also to having the edge bend sideways.
When grafting we put our knifes trough more abuse than most kitchen knifes see. So i would generaly adivise a higher than 30 degree angle if your modifying a kitchen knife to a grafting knife.
However carbon steel opinels for example have a high toughnes (resistance to cracking/chipping. They are more “bendable” less “brakable”. Whith bendable i don’t mean easy to bend. i mean they bend instead of brake)
This makes it posibble to go more around a 30 degree angle.
In the end i would aim for around 30 degree’s . And vary up and down a bit, and see what feels better.
For hard things like walnuts. or more abuse like cleft/side grafting. i would go higher angles.
For softer woods or finer movements like chip budding you can get away with smaller angles.
long story short.
Start around 30 degree’s. (higher angle 30-40 degree’s. lower angle 20-30 degree’s)
More abuse → higher angle
low toughnes steel → slightly higher angle.
More refined use → lower angle.
Higher toughnes steel → lower angle.
In the end the exact angle does not matter that much.
Id rather have a “sloppy” angle. That i frequently “polish up by stropping on the stone”. Than to have a “perfect angle”
M2 seems comparable to VG10 (slight higher hardnes edge retention and toughnes. but way lower corossion resistance)
It still seems to have a low toughness. What edge geometry do you use? (thinknes of spine and secondary/primary edge?)
And have you had any problems with chipping or cracking while grafting? Or corrosion?
Have you ever looked at
Keep in mind though, that hardnes and edge retention aren’t the only inportant things. I value toughnes and grindability highly in a knife “abused” for grafting.
People have been sharpening blades for thousands of years without jigs so I’m sure it’s possible with the right training and lots of practice. I personally can’t get nearly the same results. Im genuinely impressed and humbled that you can!
Question though, bc maybe I don’t understand the process. If I freehand one stroke at 20 degrees, and the next at 22 degrees, and the next at 18 and so on, because I can’t precisely hold an angle, wouldn’t that make it harder and take longer to sharpen the blade?
First , I never abuse my grafting knife.
I use them to do chip budding and whip and tongue on small caliper stock.
M2 steel will corrode , rust, so needs to be kept clean and oiled in storage.
Blade geometry:
I have several different ones
Some full flat on both sides, very thin.
Others flat one side bevel on other, some at different angles .
I have no way to measure the angles , so don’t know ?
What I can say is that M2 can preform very well , cutting wood at narrower angles than any other knife I have. ( commonly available grafting knives )
The only chipping I have had was on the aforementioned knife that I got too hot while grinding.
I do fear dropping these knifes, surly they would chip if dropped ,they are very thin at the edge , no microbevel .
I do understand , there are better steels for knives,but they cost hundreds of dollars.these I have sourced cheep,are more than adequate for my needs.
Thank you, oscar, for taking the time to explain those things- it was all facinating information and the video was very cool. That one post went a long way in helping me understand the terms and the “science” of knife sharpening. Now I just need to do some “hands on learning”. I’ve done enough that I can improve a really dull knife, buit have never been able to reach that really fine level of sharpness. I remember camping with a friend on a weekend hunt I saw him shaving with his hunting knife. I thought it was so funny and ridiculous and literally was poking fun at him for trying to shave with hunting knife- “knowing” it couldn’t possibly be sharp enough for that- especially not a knife as large and heavy and thick as his hunting knife. WHen I started ribbing him about it he challenged me to try it on my arm hair. Sure enough, on my very first attempt I cleaned almost every hair off the top of my arm to being smooth as a baby’s bottom! haha That was the day I started wishing I knew more about knife sharpening - but never have put the time and effort required to get good at it. Now I’m going to try. Wish I had made this a winter project when I had nothing to do.
Your certainly miles ahead of me. I hope to one day make my own (grafting) knife.
Your M2 knifes will probably be damage more by dropping than a “normal” carbonsteel knife. But i still woulden’t want to drop my knifes either. So there’s not really a difference there
Out of the easy to source steels. M2 definitly seems the best or close to the “best”
Just out of curiosity, Whats your favorite out of your different knives?
You are right, you sharpen slightly slower. or less efficient if you can’t hold the exact same angle every stroke.
However in practise, you don’t notice it. You never know how many strokes you need at a minimum anyways (every dull knife is dull in it’s own way)
So if you need a few extra strokes on the sharpening stone. Doesen’t matter. You just sharpen till you feel a burr.
The alternative is one of the systems that can hold exactly the same angle. However these use small sharpening “rods” with way less surface area. And smaller surface area sharpens slower.
Compare it to wiping the floor with a broom. but having a overlap from where your wiped before. Vs using a toothbrus to wipe the floor but never overlapping the part you cleaned already.
Ofcourse this is an exaggeration. In practise i don’t expect a large difference in speed between the systems. You will likely notice a larger speed difference from different grits. Or different quality sharpening stones/plates.
Re feeling a burr, the easiest way I’ve found is to run my fingernail along the edge at a steep angle. It is far more effective than any other method I’ve used.
For high quality steel, I have some heavily used wood planer blades that are due to be repurposed into grafting knives. I don’t know the steel grade, but it is very very tough and holds an edge exceptionally well. If you can find someone with a planer that is regularly used, you might score a few knives and repurpose them into grafting knives.
@Fusion_power
Planer blades are often ( usually ) made from M2 High speed steel.
The same material as I use from the Hyde mill knifes.
So this backs up what I say about it’s ability to cut wood a lot and stay sharp !
The disadvantage of planer blades is they can be thick.
The blanks I start with are thin as a dime 3/4 inch wide.
But yes . Planner blades would make a excellent knife !
Thanks Oscar. I appreciate you taking the time to explain. For disclosure, I know these general things about material properties of metal. I’m a mechanical engineer and have taken courses in materials science, mechanics of materials, and fracture mechanics along with the regular undergrad stuff - albeit almost 30 years ago.
BTW, in Googling inspired by this thread, I ran into what I considered a thoughtful explanation for some considerations in choosing a grafting knife:
I may not have considered it before, but one of the things I appreciate about my Tina folder is I can cut with the portion of the blade close to the handle, which allows better control for the type of cuts I usually do.
It makes it easier if you don’t worry about it. Almost all of us do a slightly convex angle anyway whether we are trying to or not. You have a slightly shallower angle on the push and a slightly steeper angle on the pull. The less you worry about this phenomenon the better. I sharpen all my knives intentionally with a convex edge and you can shave your face with them. Learning how to manage the burr is much more important than perfect angles.
Also, pay attention to what Oscar is saying as his descriptions are really good
Fooling around with gadgets and the small stones or rods that come with them takes far more time than sharpening on one good quality full sized sharpening stone.
It does not take as much practice as you think especially now that we have youtube.
I agree with Oscar that the best possible purchase is a single 1000 grit stone.
I personally use a 1000 and 2000 grit stone more than anything even though I have tons of other stones.
I don’t know whether the planer blade chunk I have is M-2 or something else, but I can tell you that if you want to forge it you’ll need a good hammer! That stuff is tough - I couldn’t work it by hand, and even after heating to a cherry heat and bending it the ground edge on it held. (Maybe I was afraid to get it hot enough. Some of these fancy steels have pretty narrow working ranges and I was afraid of burning it.) The piece I was messing with was probably 1/2" thick.
i like your link to. some good considerations.
I can say that opinel also has a cutting edge directly next to the handle.
Opinels are not completly flat though. They are slightly concave on both sides. (or at least all the ones if ever seen)
bit off topic. But that link, the guys also sells pecan graft wood. 1$ a piece. Graftwood around here is way more expensive. I gues he’s just doing it for the love of pecans and not nessesaraly for profit. Always makes me smile
@ribs1 Thanks for the compliment
i also agree with everything you said in the topic!
we seem to think alike
I have a pretty good impression of the people that show up here on growingfruit because they represent such diverse expertise, not just with growing fruit. There are a surprising number of doctors, dentists, engineers, and beer truck drivers!
