Edges... Polished? Toothy? What's your preference?

[kbuzbee]

I like my edges somewhere in the middle :)

Like 1000-1200?

Ken

[PanChango]

Before I started carrying the SB Caly, I was a fan of polished edges. With the SB Caly, the polish is gone after the first few cuts.

I still get my knives plenty sharp for my usage, but have given up polishing them.

[bh49]

I used to polish edges up to UF (2000) on all my VG10 knives. On S30V, which I didn't use for a while I preferred toothy edge and was using only medium rods. But lately I stopped using Fine and UF rods on my EDC, just to see the difference. Kitchen knives still sharpening up to UF.

[unit]

I'd say it depends on the steel. Some steels take a great polish and slice very well even when polished. It sounds odd but I have found some steels to actually slice really well when polished.

[kbuzbee]

I'd say it depends on the steel. Some steels take a great polish and slice very well even when polished. It sounds odd but I have found some steels to actually slice really well when polished.

So which steels fall into which catagory for you, Ken?

(also)Ken

[unit]

So which steels fall into which catagory for you, Ken?

(also)Ken

I have been deep into competition cutting lately so I have been playing with the tougher steels. Notable standouts are CPM M4, and 3V.

I take them up to 15k and they polish wonderfully and slice like demons.

Then again....I am finding all sorts of discoveries that are completely counter to some of the things I read on forums. No offense to anyone, but believe very little of what you read until you verify it yourself. There are some highly regarded people that share some strong opinions that I and not at all inclined to agree with.

Have fun and see for yourself!

[Cliff Stamp]

In general it is going to depend strongly on the profile. I have some knives which have edge angles of 5-10 dps and edge thickness of between 0.005-0.010" with high primary grinds (hollow/flat/convex). It is pointless to put a low grit edge on them to obtain slicing aggression because they will simply push through anything anyway without any significant force. You can slice a potato for example without even one pound registering on a scale, push right through 3/8" hemp with less than 10 lbs, which outside of a scale you will barely feel.

I take them up to 15k and they polish wonderfully and slice like demons.

What do you mean exactly when you say it slices well?

At 15, 000 grit with the edge on a competition blade which is usually 0.015"-0.020"/10-15 dps the edge should just push through any medium directly, how exactly are you determining the level of slicing aggression when the applied contact forces are going to be so very low?

That edge for example should push cut a 3/8" piece of hemp with < 10 lbs of force on a straight push, even with the mechanical advantage of a slice (without any "saw" effect), you would need to be able to measure the contact force to at least 5% to even see a difference.

[unit]

In general it is going to depend strongly on the profile. I have some knives which have edge angles of 5-10 dps and edge thickness of between 0.005-0.010" with high primary grinds (hollow/flat/convex). It is pointless to put a low grit edge on them to obtain slicing aggression because they will simply push through anything anyway without any significant force. You can slice a potato for example without even one pound registering on a scale, push right through 3/8" hemp with less than 10 lbs, which outside of a scale you will barely feel.




What do you mean exactly when you say it slices well?

At 15, 000 grit with the edge on a competition blade which is usually 0.015"-0.020"/10-15 dps the edge should just push through any medium directly, how exactly are you determining the level of slicing aggression when the applied contact forces are going to be so very low?

That edge for example should push cut a 3/8" piece of hemp with < 10 lbs of force on a straight push, even with the mechanical advantage of a slice (without any "saw" effect), you would need to be able to measure the contact force to at least 5% to even see a difference.

There are slicing cuts being added to the comps all the time. One very notable cut is a piece of foam tubing about 3 inches thick that is poorly supported on the end of a soda bottle that is also poorly supported with a single screw that allows the bottle to spin and wiggle. A push cut will pull the foam down and off the bottle, and an aggressive coarse edge will cause my bottle to spin in the fixture. A polished edge will cut thin wafers off as shown at 3:20 in the attached video.
http://www.youtube.com/watch?v=aqHN0GN5 ... age#t=200s

There are other examples...I am not going to attempt to preach or teach. I would prefer for everyone to do their own testing and arrive at their own conclusions...it is a lot more interesting to see people argue with themselves

[kbuzbee]

I would prefer for everyone to do their own testing and arrive at their own conclusions...

I agree with you, Ken and it emphasizes the vast number of factors that are "you" specific. What exactly you it. How often. If what style as well as differences in sharpening techniques. Ther are ome interesting ideas on the difference you get stropping toward the heel vs toward the tip.

Still, it's interesting to hear the experiences of folks who do more with their knives than us average bears

it is a lot more interesting to see people argue with themselves

Well sure.... Like any spectator sport

Ken

[Ankerson]

There are slicing cuts being added to the comps all the time. One very notable cut is a piece of foam tubing about 3 inches thick that is poorly supported on the end of a soda bottle that is also poorly supported with a single screw that allows the bottle to spin and wiggle. A push cut will pull the foam down and off the bottle, and an aggressive coarse edge will cause my bottle to spin in the fixture. A polished edge will cut thin wafers off as shown at 3:20 in the attached video.
http://www.youtube.com/watch?v=aqHN0GN5 ... age#t=200s

There are other examples...I am not going to attempt to preach or teach. I would prefer for everyone to do their own testing and arrive at their own conclusions...it is a lot more interesting to see people argue with themselves

Yeah, depending on the steel a polished edge will slice well, the higher alloy steels tend to do better than the simple lower alloy steels usually due to the high carbide content.

But still in Blade Sports most of the cutting done is push cutting and chopping so a polished edge will perform better depending on the refinement, get it too fine and it would just slide instead of bite.

So in the end the edge refinement has to be set to the tasks at hand for best performance as you already know.

They won't put a task in the Competitions that a polished edge won't handle as that would be counter productive.

[dbcad]

I prefer polished edges. However, if I know a knife will be used hard for a full day I would change the finish :)

[Aotea]

......I'll be interested in hearing your experiences with the S90Vs. How far polished are you taking the one? Seems like 600 would be good for the other.

For the polished one I'll go DMT EF > 1500 grit SC paper > 2000 SC paper > green compound strop. 600 grit probably for the 'toothy' other.

And I've put a 80 grit finish on both an old boning knife and skinning knife. A dozen strokes for each in their appropriate roles, feeling for cutting changes and followed by viewing the edge under microscope for retained fibers should satisfy my curiosity regarding the earlier mentioned issues.

15000 grit finishes !!! Make a scalpel seem blunt.

[Alchemy1]

I'm a polished edge guy. I just can't seem to stop once I put my knife on the WE.

[kbuzbee]

I'm a polished edge guy. I just can't seem to stop once I put my knife on the WE.

I completely get that! I mean, it's already clamped in place.... Why not?

Ken

[The Mastiff]

It depends on the knife/steel/grind and it's intended uses. I've been leaning more towards steels with bite lately and leaving them mainly DMT Coarse/Coarse though I have all kinds of equipment and can tailor an edge. When polishing I have rarely gotten above 8,000K with .25 diamond strop. I haven't really needed more. I don't do much push cutting and cut more light plastic than probably anything else.

[Ankerson]

It depends on the knife/steel/grind and it's intended uses. I've been leaning more towards steels with bite lately and leaving them mainly DMT Coarse/Coarse though I have all kinds of equipment and can tailor an edge. When polishing I have rarely gotten above 8,000K with .25 diamond strop. I haven't really needed more. I don't do much push cutting and cut more light plastic than probably anything else.

Try a coarse edge on that S110V blade, it will be like cutting with a hacksaw. :D

[Cliff Stamp]

One very notable cut is a piece of foam tubing about 3 inches thick that is poorly supported on the end of a soda bottle that is also poorly supported with a single screw that allows the bottle to spin and wiggle. A push cut will pull the foam down and off the bottle, and an aggressive coarse edge will cause my bottle to spin in the fixture. A polished edge will cut thin wafers off as shown at 3:20 in the attached video.

The action of the edge is still a push, the mechanical movement of the foam is simply due to the gross forces on the blade and the fact that a draw puts it under tension horizontally while a push loads the foam (as a whole) vertically. As you noted, as soon as you try to actually slice it (cut horizontally) with a coarse finish it moves and thus what you are doing edge wise is a pure push cut (the loads on the material at the edge are vertical).

All utility knives which cut foam have a high polish for that reason, the material isn't rigid enough to withstand the horizontal forces and it is never under tension. Plus the rupture pressure is that low that a polish works fine, there is no need to attempt to puncture the material with an aggressive finish, plus you are always doing cuts longer than the blade so a draw has to be short, i.e., it is a push.

In order to actually benefit from an aggressive (low grit finish) :

-the medium has to have a very high rupture pressure (to benefit from the high pressure points of the teeth)
-the medium has to be under tension or otherwise rigid (to allow for horizontal loading)
-you have to be able to make a long but shallow cut (mainly mechanics)

[Stuart Ackerman]

I prefer a toothy edge for most of the time...works for my daily tasks...

[mark408]

Both work well....IMO getting the proper angle and learning to get a wire edge is most important....i use a 1x42 belt for some years now....IIRC Jerry Hossom got me off the stones and on the belt.

If a knife comes with a good edge , I just hit it with a leather belt as needed (the edge soon becomes polished)...i only use a grit belt if the edge gets damaged....I convexed my ZT 561...wow just wow.