Help with sharpening...

[G. Scott H.]

I believe that "V" bevels have been around several millenia longer than convex.

I've never seen a flint or obsidian knife, arrowhead, or spearpoint that was convexed!

Pfft...The reason for that is obvious. Have you ever tried knapping obsidian on a mousepad and sandpaper?

Much of the debates on these kind of forums are a form of mental illness.

I think I'm doing a fair job of proving this point, eh?

 

[silicic]

I was under the impression that the modern flat-bevelled edge was, in fact, adopted only in the past centruy as a way to ease the mass production process.

Convex grinding was original in Sheffield's and Solingen's knife making history. It was done on water-cooled stones though. The last century, when individual skilled people stopped sharpening knives in factories, v grinds were more easy to program into CNCs so it is the cheapest way to mass produce knives, and is modern in that respect.

Knapping flint was done to a convex cross section if that matters. The individual fractured pieces are conical spalls, so technically the cutting edge is concave or hollow then.

 

[Ben Dover]

Actually, the only reason for convex edges today is economy. They are easy to make on commercial belt grinders by semi-skilled operators.

 

[silicic]

And... a CNC requires no human operator for sharpening. When humans were sharpening in Sheffield they convex ground. Both sides could juggle rhetoric endlessly, but if 1 side argues using slack belts is economical, a large number of people also argue that putting on a bevel (referring to the advent of CNCs) is the cheapest way to make a knife.

 

[Jason B.]

I don't think I'll ever understand why there is always a argument over convex and its abilities or where it came from. Its a very simple solution to making a thick piece of steel cut like a thin one. Its not hard to see the abilities of a convex blade when your using one, if you have and still think its a uneffective grind then that's your opinion, I call it user error though.

 

[learnme]

OOOK, this is getting way out of hand. First of all, this is thread started on the "Maintenance, Tinkering & Embelishment" section of the forum. This not a Convex vs Flat thread. I do appreciate any and all feedback that are on topic as they are constructive and informative, anything else is not appreciated as they are destructive and generally a waste of time. I and other readers around the world who come on here would really appreciate it if posters FOCUS and STAY ON POINT. I need help with sharpening so that ultimately I will be able to properly be able to sharpen my F1 which is a convex. It was my choice after a lot of reading that I WANTED a convex ground edge and am more than happy I did because it suits my needs just fine. I am done with deciding what steel, what edge, what brand, etc etc I was going to settle on and now I need help moving on to sharpening and care for a blade that I personally want with me for a very long time. Debate is over, if you don't have anything new and constructive to add then please do not post rubbish.

Now, back on topic. Again, a big thank you to Ed. Good sound advice is hard to come by and even if it is hard to explain you still give it a shot. Thank you for that. I am a little unsure though of what exactly a "wire edge" is. I googled it before writing this and to my understanding, it is just the shavings of steel that come off the knife due to the sharpening process. I'm a little confused because you said that I could feel this by running my fingers from spine over the edge. I'm not sure what you meant by this. Well, I look forward to more constructive feedback and am now off to go practice some more.

 

[Donnydo]

The "wire edge" is the burr that appears on the opposite side of the knife. As you work on the left bevel, periodicially check for it on the right bevel. I run my finger nail perpendicularly over the edge: on the side you sharpening, you should feel nothing; on the opposite side, should start to feel your nail catch on the burr, or wire edge. Once you have raised the burr along the whole length of the edge, start to work on the other side. The wire edge, or burr, is evidence that your sharpening has reached the very edge.

Hope this clarifies.

Joe

 

[GrinderMcgee]

The wire edge is the burr that forms opposite the side you are removing metal from. You can feel it by running your fingers over the edge of the knife, from the direction of the spine to the edge.

Hand sharpening is one of those things that takes practice and patience, the results are not immediate like some make it seem. My suspicion on why your kitchen knife took a 40 degree cutting edge is that it was so dull, what the edge really needed was a re-profiling, or new edge bevel. This is something that, for me, takes an eternity on hand tools and is where the respect for guys like Ed comes from. Color the edge with that sharpie, trust the 'ole gut, take a few slices at the coarse stone where you feel the edge should be working, look at where the material was removed, and if it was on the back-bevel, or shoulder of the edge, either fire up the belt sander or get in a happy place and start putting steel to stone at that angle. Most like their kitchen knives at, or under 20 degrees. Regular maintenance can help avoid having to regrind an edge this way. Eds granny was able to sharpen her blade on the stoop because every time she didn't like the way it sliced a tomato, she touched it up.

 

[Foxer]

Honestly, I recommend you regrind the bevels to a V or saber grind. It is much easier to maintain

That is just simply not true. I own just about every type of bevel there is, and convex is by far and away the easiest to maintain and i do it with no tools whatsoever. Just a bit of leather and some sandpaper and polishing film.

Where on earth did you get the idea you need any 'belt' equipment to maintain a convex edge?

 

[Bushminer]

Knapping flint was done to a convex cross section if that matters. The individual fractured pieces are conical spalls, so technically the cutting edge is concave or hollow then.

Have a couple of "firestones" from the Solomons. Story (modern) is they are meteorites. They were found after loud bang and tree caught fire so locals looked around and found these stones (of a type bit like jadeite/greenstone not found on the island) which the educated said must from a meteorite. 1st one maybe even if it did look like a minature New Guinea stone axe, 2nd identical shape but different size is stretching probability a lot.

Stereo microscope clearly shows the grind marks on the convex edge even though one is ground parallel to the edge and one at right angles to the edge. Presumably from a previous people/culture.

 

[dantzk8]

OOOK, this is getting way out of hand. First of all, this is thread started on the "Maintenance, Tinkering & Embelishment" section of the forum. This not a Convex vs Flat thread. I do appreciate any and all feedback that are on topic as they are constructive and informative, anything else is not appreciated as they are destructive and generally a waste of time. I and other readers around the world who come on here would really appreciate it if posters FOCUS and STAY ON POINT.

However, digressions are the salt of the conversation. My pleasure would be to read Ed Fowler's digressions. I would learn a lot.

I am a little unsure though of what exactly a "wire edge" is

.

I've yet said you it in an other thread. Take a Mora, lay one of the bevels flat on a stone. Gently push edge forward. do it until you feel under your nail a burr on the opposite side. That's a wire edge. Remove it without pressure at a steeper angle. Make the same on the other bevel. Your blade is sharpened.
If i advise you to first make it with a Mora it's because you won't have in a first time to worry about the angle, because the steel is soft enough to get a quick result (patience is a skill), because you will learn, too, by ruining some edges. It's better if they are unexpensive.

dantzk.

 

[learnme]

oook, Im feeling really stupid now because I still am not 100% sure what a wire edge is. I'm just going to say its the metal pieces that come off the knife during sharpening.?. So, moving on, I just read a few stone sharpening articles and they say that you should sharpen by pushing into the stone like you are slicing into it instead of pulling away. IS THIS TRUE? They also say that you should have equal strokes per side, meaning if you do five on one, you should do five on the other...again, is this true? The reason I ask is because in reference to this, sharpening should happen in sequence like 20 20, 10 10, 5 5, 3 3, then finally one lick per side. If so, how can a wire edge/burr form on the opposite side? Lastly, can I use my leather belt as a stop? If so, what side should i use?

 

[dantzk8]

So, moving on, I just read a few stone sharpening articles and they say that you should sharpen by pushing into the stone like you are slicing into it instead of pulling away. IS THIS TRUE?

Yes. Put your blade flat on the stone, lift the spine to get the angle you want to sharpen at. Push the blade (edge forward) like to "shave" the stone. No pressure, no strength.

They also say that you should have equal strokes per side, meaning if you do five on one, you should do five on the other...again, is this true?

No. You do that only when you want to modify the bevels angles. To keep the symetry of the bevels you have to grind the bevels symetrically (10 strokes per side, for instance, and so on) until the meeting of the two bevels.

When you want to sharpen an edge without changing the bevels angles, in other words when you want to restore an edge, put a bevel on the stone, process as said before ("shaving" the stone) until the very edge is so thin it bends under the pressure. You have got then a burr you can feel under a nail on the opposite side of the bevel you are working on. Remove the burr by using a steeper angle as gently and lightly you can (i do it on a fine stone but opinions may differ about the grit choice). Do the same on the other bevel. At that point the two straight lines of the bevels are meeting. Your knife is sharpened.

Lastly, can I use my leather belt as a stop? If so, what side should i use?

Not only you can but you should. Use the less rough one, usually the outside of the belt. It will refine the edge, leather is abrasive, and will "clean" the weak teeth of the edge. You can find quality leather and compound for instance here:

http://www.handamerican.com/benchhone4.html

About that topic the best is you look at the posts of Knifenut1013, an expert. Have a look too at this thread:

http://www.bladeforums.com/forums/showthread.php?t=634739

Hope it helps. Don't jump on your knife and stones. More aknowledged members wil correct me if i'm wrong and provide advises.

dantzk.

 

[Ed Fowler]

Learnme: You have inspired us to do a DVD about sharpening a blade. We hope to start on it in the immediate future. So smoke just a simple how to and a little theory. It will be a month or so until it is ready, but will announce it on my form and here.
Thanks for the motivation!

 

[hardheart]

who sharpens knives on a cnc mill?

Convex and V grind are the same thing, taking a piece of steel an making one edge thinner than the other with an angle that increases toward the cutting edge. Adding a microbevel makes them even more similar.

 

[Hitthespot]

If you ever find your way to Riverton Wyo. stop by for a quick lesson or two.

Now there is an honor I wish I could use. Too bad you don't live next door.

Bill

 

[Donnydo]

So, moving on, I just read a few stone sharpening articles and they say that you should sharpen by pushing into the stone like you are slicing into it instead of pulling away. IS THIS TRUE?

No. You can push the edge, you can pull the edge, you can push and pull the edge back and forth; you can move the blade left and then right. You can also make little circles or figure eights. What matters is that you have control of the blade and keep a steady angle.

They also say that you should have equal strokes per side, meaning if you do five on one, you should do five on the other...again, is this true? The reason I ask is because in reference to this, sharpening should happen in sequence like 20 20, 10 10, 5 5, 3 3, then finally one lick per side. If so, how can a wire edge/burr form on the opposite side? Lastly, can I use my leather belt as a stop? If so, what side should i use?

This is a different technique from raising the burr. It assumes that you are hitting the bevel and edge perfectly (or that it is close enough), or that the knive is still reasonable sharp.

I raise a burr on one side and then raise it on the other, thus making sure that I have brought the edges together. Then I refine and polish the edge by doing equal number of passes on both sides, proceeding to the finer stones and finishing with the strop.

Joe

 

[learnme]

Learnme: You have inspired us to do a DVD about sharpening a blade. We hope to start on it in the immediate future. So smoke just a simple how to and a little theory. It will be a month or so until it is ready, but will announce it on my form and here.
Thanks for the motivation!

WOW, the only thing I can think to say now is thank you sir and that I only hope to get a hold of that DVD for Xmas. *do you think you could make a little shout out to me on the DVD? My friends would flip and I would be on cloud nine! HAHA

As for using my belt as a strop, I am just starting out and haven't bought any compound yet. IS there any point in stropping without compound?

 

[CAS6591]

In my opinion, this tool is the only way to go for convex grinds.

I met this person through a knife forum, and we have had many conversations about sharpening. Although not unlike other 'systems', he has a bent guide rod that allows the sharpening plate to arc properly to sharpen convex blades. Very simple and effective system.

www.edgepal.com

 

[dantzk8]

You can push the edge, you can pull the edge,
Joe

It makes a difference.
When pushing you compact the burr towards the edge, when pulling you stretch the burr with the risk to tear it off in the same time you raise it.
An experienced grinder will easily deal with that, but a beginner, what Learnme is, won't be able to know if he still has to raise a burr or have yet removed it.
That's why i recommended him the pushing process.

dantzk.