New to sharpening and the forum

bgentry said:
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A more coarse edge will really "hook into" what it is cutting. Which makes cutting slick materials (like soft tomatoes) easier. Really polished edges can slide off of slick material.

Back to paper for a moment. Try these exercises:

1. Cut paper along one of the factory edges. Notice how it cuts.
2. Turn the paper 90 degrees and cut along a different factory edge. Do you notice a difference? You should because the grain of the paper runs through it and going with the grain is easier and against the grain is harder.
3. Get a fresh sheet and start with the "easy" side (with the grain). Line your blade up with the paper. Now notice that there are 3 axis that you can move the blade relative to the paper:
A. You can lean it over and cut a triangle off of the paper. Keep it as straight up and down as you can, so it cuts a rectangle. This is harder than an angled cut.
B. Start again and notice that you can rotate the knife so that it is straight like in (A) above, but the blade is angled with the *edge* of the paper. Make that angle 90 degrees. This is harder.
C. Start again. Line up like in (A) and (B) above. Notice that you can tilt the back of the blade up or down, which makes yet another angled cut into the edge of the paper. Make this 90 degrees also. So 90 degrees in all three dimensions directly into the edge of the paper. This is the most "pure" push cut you can make and is the most difficult.

Many very sharp edges can't really start a push cut into phonebook paper with a pure 90 degree cut in all dimensions.

Try this with the grain *and* against the grain. Against the grain is quite difficult. My super polished edges from the Spyderco UF could push cut, against the grain, with a 90 degree angle in all 3 dimensions. Less polished edges will struggle to do it....
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Wow, thanks a lot for your input! So you are saying that when those guys cut extremely thin slices of a tomato (without even holding it in place), they probably finished their edge on a coarse (medium at best) stone? This is so counter intuitive... but it does make sense that a very polished edge might not "bite" and actually slide off. I would love to test it and check for myself.

As for the tests, I will be honest with you... it's a little hard to visualize exactly what you are describing. I find it specifically hard to know what's the grain direction in the paper. HOWEVER I think I get most of it and it boils down to experimentation. You made it clear... the angle you approach the paper on all 3 dimensions will change dramatically how the knife performs, being influenced both by the angle of the blade and also by the constitution of the paper. I'll experiment and check if a knife that seems to cut buttery smooth (on my tests) can still perform well cutting paper in several different ways.

I already got that nothing will replace experimentation. It's kinda addicting. lol

Mr.Wizard said:
This is what I was talking about earlier in this thread:

A higher grit stone is the easiest way to reduce a burr and get a sharp edge, at least for me. If you don't need the "low-grit aggressive toothy edge" I mentioned you can absolutely finish even "crappy" knives on the 6000 grit stone. An edge properly finished on 6000 grit will not perform worse in push cutting than one finished on 1000 grit. The initial drop in sharpness is faster but it stays at or above the level of the 1000 grit edge after the same amount of work. If the edge fails quickly you probably had a wire edge: a kind of burr that is aligned and strong enough to cut but not to last—this can happen even on fine stones. The other possibility is that you're trying to put on too acute an edge for that steel to handle, but that will be the case for coarse or fine grit finishes alike.
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The more I experiment the more even the previous comments make sense. This too.

However I think I got to a point where I'm actually able to remove a burr completely (or it feels like it) even on a coarse stone. It cuts through paper and doesn't catch... It just feels much more buttery smooth after I've put some time on a 6000.

I'll try to put some more time on just the coarse stone to see how sharp I can get a knife, and I really want to try and thin slice a tomato with it!

My coarse stone is only 320 though... maybe that's too coarse to get decent results.

a 400 here is kinda cheap but feels like a waste moving up just that taddy bit. I'm inclined to get a King 800 for that (not that cheap... at least here in Brazil), but I honestly feel like I've spent too much money already on something that I have just begun doing (and you guys know how these things go... you never know if I'll get bored in 1 month and never sharpen again... I'd feel better to wait a little longer before investing any more dough in this).

BTW, you guys are awesome... I love internet forums, there's just something about sharing knowledge. Hopefully I'll soon have something to add myself.
 
I've been cutting paper both with and against the grain without knowing there would be a difference... But I've been cutting at angle... much easier to cut.

I'll try today to cut paper at a 90º again with my sharpest knife... see just how sharp it really is.
 
brukuns said:
Wow, thanks a lot for your input! So you are saying that when those guys cut extremely thin slices of a tomato (without even holding it in place), they probably finished their edge on a coarse (medium at best) stone? This is so counter intuitive... but it does make sense that a very polished edge might not "bite" and actually slide off. I would love to test it and check for myself.
Click to expand...

You can round the apex when polishing but that is a mistake, not an inherent character. Any sharp (keen in Todd's terminology) edge will "stick" and this is often used to check an edge during sharpening, either on a thumb nail (carefully), the barrel of a Sharpie pen, or the hair on the back of the head. The angle of stick vs. slide is informative.

Tomato skin really isn't that hard to cut either; a knife has to be pretty dull by hobbyist sharpening standards for it to slide on a tomato.
 
brukuns said:
So you are saying that when those guys cut extremely thin slices of a tomato (without even holding it in place), they probably finished their edge on a coarse (medium at best) stone? This is so counter intuitive... but it does make sense that a very polished edge might not "bite" and actually slide off. I would love to test it and check for myself.
Click to expand...

I may have misled you a bit. A nice thin edge that's polished generally can cut tomatoes quite well. Though I notice that with a highly polished edge, you need to "saw" through the skin to start the cut. This is highly dependent on how thin the edge is, and whether or not the edge has any "teeth" left. It's possible to start an edge as coarse (so it has some jagged structure) and then polish it so that you don't remove the jagged parts. You "polish" them. This is sometimes called a polished toothy edge. This rabbit hole goes deep my man. :)

Try your edges on synthetic rope or plastic packaging. Both are tough and slick and will show you major differences between coarse and polished edges.

As for the tests, I will be honest with you... it's a little hard to visualize exactly what you are describing.
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Yeah, sorry about that. Words are very difficult when describing geometry. As you said, play around with it and you'll find some interesting differences I think.


My coarse stone is only 320 though... maybe that's too coarse to get decent results.
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On my belt sander I'm getting extremely sharp edges that do quite well with phonebook paper, easily shave hair, and score 150 to 170 BESS on the tester. I'm using a 180 grit belt to do this. Belts are a little different though, as they move fast, so I think they produce a more fine edge than the grit indicates. 320 should produces a pretty nice toothy edge. Try it!

I really like reading about your enthusiasm and your progress. Keep at it. I think you are one of us. :)

Brian.
 
:D:)

Mr. Wizard and Brian, I can't thank you enough for the tips!

Yesterday was tough, I didn't have time to do anything. All I did was grab that Santoku (which I mentioned was my best sharpening yet) to try and cut paper in different ways like Brian mentioned... And to my surprise, when I inspected the knife there was a tiny dull spot reflecting light. What the heck!? I could have sworn I placed it very carefully in a protected part of the drawer. It must have touched another knife when I opened it a few times. I'll retouch it when I have the time.

I avoided the dull spot and just tried to push cut the paper on a 90 degree angle. I could but only if I went very slowly. Even then I had to do at least a very tiny slicing motion to initiate the cut. Now I have another goal... I want to make a knife push cut with less effort. Or at least slice cut at close to 90 degrees (is that a thing?)

There's one last thing that I'm kind of avoiding but I'll have to go there eventually...

1. Thinning out knives. Is it really necessary? Can I compensate for this just by grinding a wide bevel on a very low angle before putting an edge at a slightly higher angle? Because the one knife that feels need more thinning is exactly the one knife that has kind of a bolster and doesn't have an obvious primary bevel (or was it secondary? It's the bevel before the actual edge). So If I try to thin it I'll end up with a weird pattern on the knife.

Also, I don't use that one knife to cut vegetables... just meat. I think meat probably can handle a bit of a wedge (if that makes sense). I'm hoping I can skip thinning this knife and still have it scary sharp (eventually).

2. Polishing my scratched up knives. I scratched a lot of my knives practicing and at some point I would like to fix them... at least my better knives. Should I just use regular wet sand paper? Start on a lower grit (maybe 220) and progressively move to higher grit paper, maybe up to a 3000 grit? Will that polish the knives enough? Or am I missing something?

Thanks again guys, Happy Friday!
 
It is great to see that you are getting the hang of sharpening.

What helped me when I first got into sharpening seriously was sharpening all my friends and relatives knives.
This made me have to evaluate each edge and then decide where I needed to start and finish grit wise.

It helps to use the sound of the stone also when grinding.
On most steel I can hear and feel when I am not precisely on the bevel.

Thinning a knife is necessary sometimes and that is a good thing to learn but I have only come across a few older knives that really needed it.

Now lowering the edge angle is a different thing and I find most knives need this done to make them cut to their potential.

Keep on sharpening and look out for old stones at flea markets or second hand stores to round out your supplies of tools.
I have picked up a few nice stones for next to nothing and these are great to experiment on.
 
willc said:
It is great to see that you are getting the hang of sharpening.

What helped me when I first got into sharpening seriously was sharpening all my friends and relatives knives.
This made me have to evaluate each edge and then decide where I needed to start and finish grit wise.

It helps to use the sound of the stone also when grinding.
On most steel I can hear and feel when I am not precisely on the bevel.

Thinning a knife is necessary sometimes and that is a good thing to learn but I have only come across a few older knives that really needed it.

Now lowering the edge angle is a different thing and I find most knives need this done to make them cut to their potential.

Keep on sharpening and look out for old stones at flea markets or second hand stores to round out your supplies of tools.
I have picked up a few nice stones for next to nothing and these are great to experiment on.
Click to expand...

There are a lot of guys at work already telling me they'll send me their knives for sharpening (because I keep babbling about it. :D)

I told them I still need to get the hang of it. My knives are getting sharp, but scratched up too! I also didn't really test how the edges are holding... probably not very good. Beginners will be beginners.

I'll definitely keep an eye out for good cheap stones... Sighting a King 800 as of now :)

Tomorrow is BBQ time, I'll pick one knife and get it proper sharp before hand for some meat slicing action! I'll post the pics here if I don't forget to take them (BBQing is what started this whole thing for me to begin with). I have a mean beef short rib I'm gonna grill the F out of it!
 
lonestar1979 said:
Lower the angle,and get consistent burr along whole blade,then raise angle little and alternate sides to take burr off.Most knives when new from factory are thick behind edge and need to be thinned out,after that sharpening is easy.
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+1

bgentry said:
Paper cutting tests a few things. One of the big ones is burr removal. If your edge still has burr on it, paper tells you because it hangs, catches, and tears the paper. If your edge is dull, paper tells you because the blade will not initiate the cut. In fact it can tell you some relative sharpness depending upon the exact cut.
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Good info! :thumbsup:

Thanks!
 
Put some serious time on that one good knife I have... amazing how I jusy can't seem to put on a properly sharp edge on that knife... not sure if it's because the steel is a bit harder or if it needs thinning... probably a bit of both.

I'm ready to give up on that knife and put more time on cheaper steel for now, at least to avoid some frustration.

It did cut well enough for it's intended purposes though. Now for that BBQ update... Medium rare anyone??

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Today was gooood.
I decided to leave the bigger knife aside (the thing needs some thinning for sure) and instead decided to improve an already pretty sharp knife I had worked before.

I noticed that the heel wasn’t really sharp and the tip was terrible, so off I went straight to the 1000 (it was pretty sharp already to go any coarser),focusing on those 2 areas but sharpening the whole thing to make it even. I made sure to keep the lowest angle I could hold, lower than on my previous attempts.

felt pretty sharp, so I moved on to the 6000. Same thing, just less pressure. Stropping forever before trying it out.

pretty sharp! But the freaking tip was still dull! So I put some more time on the 6000 focusing on the tip and did it all again on this stone.

End result: blade still pretty sharp, specially the heel, which seems to be sharper than the rest now... and the the tip still crap, but definitely better. I’m satisfied.

now I know the I need to work on those tips. Feels like I’ll dig into the stone if I lift it to much to get the very tip’s edge.
 
Hey guys, quick question.

I want to polish one or 2 knives by sanding it (all the way to 3000).

I don't have a workbench... do you think it's too dangerous to simply sand the blade by hand without clamping it on anything? I would be pretty much holding the knife with one hand and sanding it with the other.

Also, even if I do find a way to clamp it, I'll just clamp it on top of the handle, afraid it might damage it. No way I'm removing the handle for this.
 
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You can't lay the knife flat on something so that the edge is against a backing surface? If not I'd definitely use a cut resistant glove.
 
Mr.Wizard said:
You can't lay the knife flat on something so that the edge is against a backing surface? If not I'd definitely use a cut resistant glove.
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I can lay it flat backed against something. But I can’t secure it in place.

I could get a C Clamp and use it on a table here (my wife wouldn’t be too thrilled), but I’m afraid fastening a C Clamp directly on the knife’s handle could possibly damage it.
 
brukuns said:
As for the tests, I will be honest with you... it's a little hard to visualize exactly what you are describing. I find it specifically hard to know what's the grain direction in the paper.
Click to expand...

This thread and this post specifically made me want to make a video about paper cutting. It's been a few weeks and I finally got around to it. Here it is.


Brian.
 
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