How detectable is the diff. in steels/sharpness?

[ChristopherG]

Okay, guys, I've just gotten on board this whole sharpening project. I now see how it becomes a thing in its own right, the quest for the perfect edge. And, I see how it combines with an interest in blades--much as my interest in firearms took on a whole new level of complexity when I took up reloading.

I've got a couple of sharpening tools--diamond stones, a sharpmaker, home-made strop--and I've been fiddling around putting different edges on two carry knives, primarily: a Spyderco Cricket (VG10) and a Benchmade Griptillion (440c). Thing is, I just can't get that Grip to take a reach-out-and-bite you edge like the Cricket will. It'll get sharp, and cut paper real nice, but I believe I can feel and tell a difference in the sharpness of these blades, and this raises my question.

I've assumed that the main difference between high-grade steels was in how well they HELD an edge, rather than how sharp you could actually make them. Is it possible or likely that I'm actually detecting the greater edge-TAKING ability of the VG10? Or is is more likely that something like edge geometry is playing tricks with my head?

Can you tell the difference by feel, or by push-cutting a pencil or whatever test you use, in the sharpness of a freshly-honed edge between two high-grade steels?

 

[TedGamble]

Hopefully, you will get some very informative information as others respond to this thread, but there is a difference in both the SHARPENABILITY and EDGE HOLDING properties of steel. Some steels can take a smaller angle than others (sharpenability) due to their ability to not fracture as the edge narrows. You are in for a HUGE AWAKENING my friend - your world if about to be turned upside down.

 

[DGG]

Hi and welcome to the party.

I've reloaded 12/20 ga. shotshells and 22-250 benchrest rifle ammo (22-250 was a wildcat for a long time) for many years. Great fun and saves a buck here and there.

Here is a decent link with pictures. VG-10 is a rare steel because it has Cobalt in it, none of the others have this. Also Spydercos hollow grinds most of their knives, a "saber hollow ground" I think they call it. I think this thins and narrows the secondary blade edge on the Spyderco more than on the Benchmade's.

http://forums.egullet.com/index.php?showtopic=26036

Our resident knife wizard guru Mr. Joe Talmadge has some thougths that I'm sure he forged over many years of knife making and sharpening experience.

If you look at the very top of this forum you will find this thread. I think it should be a requirement for any newbie to read it and pass a test.

http://www.bladeforums.com/forums/showthread.php?t=368828

I'm sure you will enjoy this learning process. There are some great teachers in this forum that have been a great help to a klutz like me.

 

[Cliff Stamp]

...something like edge geometry

That would be the first thing I would check, Benchmade in general runs much more obtuse angles and at the same level of sharpness a more obtuse angle will in general have lower cutting ablility (aside from wedging effects which can at times be positive).

I have seen differences in steels in regards to final edge sharpness, but usually this isn't because of an inherent lack of ability, but factors which make achieving it very difficult. Softer steels for example, in particular the softer stainless, tend to burr badly and it can be very difficult to minimize this burr especially on sharpening rods.

Machinability is also a large factor, some steels can take multiple times the honing time length of others and thus it takes a lot more work to get there from an equal state of bluntness. If you are counting strokes or otherwise give up prematurely then you can have a low opinion of the steel.

However if you take blades to really low angles and/or have really high standards, you consider the ability to slice paper to be fairly dull for example and the point at which you actually sharpen you using knives, then it is likely that you will see an actual measurable difference in sharpness due most likely to the carbide and grain size of the steels.

-Cliff

 

[ChristopherG]

Ted and DGG, thanks for the welcome. I have read a couple of Joe's stickies, DGG, and agree, they are a rich mine of information. Really, it was Joe's discourse on sharpening that first piqued my interest in the whole process.

Cliff, thank you for your reply; I've read around enough here to know that you are rich resource yourself. In quest of a better edge, I've taken the both knives down to 30 degrees inclusive with patient reprofiling, based at least in part on your experiences and stated opinions (well, the Cricket was pretty much there already; the Benchmade was, as you note, a bit more obtuse to start with).

Since my inquiry, I've been getting a little more promising result with the strop on the Grip. I think I may have been a little too aggressive at first. Sharpening is really a discipline of patience, it appears. Precision will get it, and force will just screw it up. Still, I'm finding it very interesting how these different steels (as well as the 0170-6c of a BK7 I'm fooling with) respond to different methods and feel at different degrees of polish. It really makes me want to fool with a blade of other steels like s30v and D2 and, well, just all kinds of things.

Do you think I can achieve a quality edge on these steels at a 30 inclusive angle? And would you expect 440c and 0170-6 to hold up alright at that steeper-than-factory grind?

Thanks again, all, for your encouragement and guidance.

 

[ghost squire]

Theres definately a noticeable difference in steels and sharpness between them. However this is often exaggerated by the fact that low grade stainless steels are brittle to begin with and therefore far more likely to be less hard then for example 1095 or VG-10 (Fallkniven makes VG-10 knives at like 59 RC).

I think if you compared 59 RC 1095 to 59 RC 440C the differences would be less apparent although definately still there.

 

[bbcmat]

The best edge depends on the material being cut and the style of cutting, then moderated by the tolerance for maintenance keep that edge.

Example - if I give you a blade made of a material with a very fine grain structure - sharpened to a smooth finish and low angle - it will open a envelope or cut paper like a lazer. WOW !~!

Now move up to cardboard and it still cuts superbly - but for a short amount of time until a tuneup is required.

If the edge folded over - I could resharpen at a less acute angle to support the edge - however, it will never glide through paper as well as the original blade. (compromise)

If I keep the original angle but make the same material harder - it will cut the same, and last longer - but may fail by chipping instead of folding (brittle) - and require alot more work to tune up. (compromise)

NOW - same situation bit different cardboard - gritty abrasive cardboard. The edge does not have a chance to fold over, it's actually worn away and dulled. Making the material harder will improve the situation but re-introduce the brittleness issue. I could introduce extremely hard (wear resistant) components to the blade composition. These hard marbles in the matrix increase the wearabilty of the edge - but reduce the smoothness of the edge. Now it will last longer but never glide as smoothly as in case #1 (compromise).

Your best edge is found through experimentation using your typical cutting situation and your tolerance (or enjoyment) for maintenance of that edge.

Now - the edge is only as good as the attack angle of that edge - and then you are off into blade shapes as well as materials and hardness / brittleness.

I find Cliff Stamp's testing valuble and important - allows someone to pick the best compromise out of catagories that are most applicable to their usage patterns (from roofer to chef).

IMO

MAT

 

[bbcmat]

Opps - babbled alot but did not answer the original question.

Yes - the differences between steels - when sharpened to best use the characteristics of the steel in your cutting patterns - is obvious. Factory grinds are middle-of-the-road compromises that can be customed to your situation and provide an improvement in performance.

MAT

 

[Cliff Stamp]

Do you think I can achieve a quality edge on these steels at a 30 inclusive angle?

This is above average, if you are planning on using the Sharpmaker I would reduce the edge down a further 1-2 degrees by hand this will allow a micro-bevel at 15 degrees with the sharpmaker which will greatly speed up resharpening.

This is a fairly robust profile in general, you are looking at metal/bone cutting to overstress it in general. If you drop it down to a full ten degrees or 20 inclusive then you can start to have some problems on harder wood work with some steels.

In regards to stropping, it works best as a final adjustement to an already sharp edge, trying to use it to do too much rarely is of beneft as it pressing really hard. This just tends to deform the leather and round the edge over.

-Cliff

 

[ghost squire]

These hard marbles in the matrix increase the wearabilty of the edge - but reduce the smoothness of the edge. Now it will last longer but never glide as smoothly as in case

Wait... what? Are you serious, I never knew that. Do you mean adding carbides and stuff (what stuff by the way) will make the knife cut less smoothly?

 

[HoB]

That would be the first thing I would check, Benchmade in general runs much more obtuse angles and at the same level of sharpness a more obtuse angle will in general have lower cutting ablility (aside from wedging effects which can at times be positive).

I have seen differences in steels in regards to final edge sharpness, but usually this isn't because of an inherent lack of ability, but factors which make achieving it very difficult. Softer steels for example, in particular the softer stainless, tend to burr badly and it can be very difficult to minimize this burr especially on sharpening rods.

Machinability is also a large factor, some steels can take multiple times the honing time length of others and thus it takes a lot more work to get there from an equal state of bluntness. If you are counting strokes or otherwise give up prematurely then you can have a low opinion of the steel.

However if you take blades to really low angles and/or have really high standards, you consider the ability to slice paper to be fairly dull for example and the point at which you actually sharpen you using knives, then it is likely that you will see an actual measurable difference in sharpness due most likely to the carbide and grain size of the steels.

-Cliff

I think Cliff's answer pretty much covers exactly what I would have said.

 

[ChristopherG]

...if you are planning on using the Sharpmaker I would reduce the edge down a further 1-2 degrees by hand this will allow a micro-bevel at 15 degrees with the sharpmaker which will greatly speed up resharpening.

That sounds like an excellent suggestion, and I'll give it a try. Thank you for your insight and expertise.

 

[bbcmat]

Ghost - I was being deliberately general - if the grain structure of a material is made coarser by the addition of larger components - then the smoothness of the edge is compromised - no real magic there. (bigger lumps mean more bumps - LOL)

I did want to imply that all components that increase wear resistance also increase the coarseness of the grain structure.

MAT