Sharp Thoughts

[db]

Sharp Thoughts, my sad rip-off of Deep Thoughts. This is my opinion on angle control and sharpness. I dare say that holding a perfect angle is way over blown. In fact I don’t think it really matters much at all. A swing of 1 or 2 degrees either way from a predetermined angle doesn’t matter as long as you don’t raise the sloppiest stroke higher than the angle you want. For example you want a 17 degree edge stroking between 15 and 17 degrees will give you just as sharp an edge as a perfect 17 degree bevel. Maybe even a little better, as the15/17 edge bevel is really kind of a convex bevel. I personally even hold my angles much sloppier than that, witch produces a large shallow convex edge. I just make sure I don’t raise the spine more than I want the edge angle to be. I do all of this on bench hones free hand. So to me angle control really doesn’t mean much to me more important is thickness of the edge and edge finish. Thoughts? Comments? Do you think I’m nuts?
This has been Sharp thoughts by db the angle control troll.

 

[Chris "Anagarika"]

Exactly ..

There are other post about convexing SAK by doing freehand sharpening. It seems that naturally we do if we use free hand method.

 

[Gryffin]

Nope, you've got a point. So long as you control the maximum angle, any deviations just round off the shoulder of the edge, leaving a semi-convex edge.

The only downside is, you remove more steel, hence it takes more time -- at first, at least. Repeated sharpening shouldn't take much longer than if you maintained a constant angle; you're stoning a larger surface, but not too much larger.

 

[Cliff Stamp]

No method gives exact angles, it isn't like the Sharpmaker is 20 degrees exactly on every pass, even angle clamps change the angle depending on the force applied and the flattness of the stone. The more controlled you are the faster you can sharpen because any angles less than the one required to hit the edge just grind above it and don't sharpen the blade at all but reshape it. Of course there is more to ease of sharpening than angle control, you can be fairly sloppy with a micro-bevel and hone *MANY* times faster than an angle guide working on a full bevel because it has to remove 100 times as much steel. Alvin has always maintained on rec.knives how freehand sharpening produces convex bevels naturally which are superior to v-ground jig bevels, which lead to Thom's post here awhile back on such a method applied to high hollow grinds, which stirred up debate on how such methods "ruin" blades.

-Cliff

 

[OleyFermo]

My method for sharpening is a little out of the norm, I believe. I hold the knife in my left hand (being right handed), and stroke a diamond hone up and down the blade edge with the intent of both sharpening AND reshaping. A little reshaping should take place each time a blade is sharpened so that the same profile is maintained on, say, the one-eight inch of blade just above the edge. I keep the diamond hone in contact with the blade at all times, applying more pressure on the area of the blade being reshaped, less pressure on the edge... since to set an edge requires almost no pressure unless it's somehow been nicked or otherwise deformed. I alternate honing from one side of the blade to the other every so often until a wire is formed. After that the wire is stropped off on leather to which a bit of white diamond compound has been applied. All my edges are convex, even on those knives which, at first glance, appear to be chisel ground, and honing freehand is the best way that I've found to keep a convex edge 'convex.

In my shop I use a large hone (two hones, actually, one 600 grit and one 1200 grit, depending on how much work needs to be done)... 3 X 8 inches, I believe... and leather glued to a steel plate. In the field, I use a much smaller hone and strop on a piece of leather belt that I hook over a limb stub.

Works well for me.

Cliff: Really enjoy reading your reviews. It's great to see someone putting as much work as you do into objective testing. Keep up the good work.:thumbup:

Jimmy Fikes

 

[db]

Some good responces. The reason I wrote this is because when I was trying to learn how to sharpen I’d think to myself I can’t hold a consistent angle and that is why I am not getting a sharp edge. Even after I started getting good edges I still thought the same thing and used jig systems for a long time. Once I decided I was going to learn how to free hand sharpen the myth of angle control disappeared. I still am learning how to get better at sharpening but am very happy with what I can do free hand. Nothing surprised me more than how easy it really is to free hand sharpen. And I’m getting my edges sharper than ever before. Sharpening is a lot easier and faster now than it ever was with the jigs and systems I used. My best sharpening advise is get the edge bevel ground to a good point with the coarsest hone. That was my biggest problem I moved to a finer hone way too quick.

 

[D_R_Sharpening]

I think that it's important to try to get even angles but it's not quite so important to actually do so.


--Dave--

 

[thombrogan]

db,

Threads like these are why chiclets are needed! :thumbup:

Which sharpening systems and jigs did you use?

I think, and Cliff's allusion to my earlier thread is a perfect example of this, that sharpening jigs are best used for knives that people want to kind of try, but still be able to resell down the road. The faceted edge you can leave with an EdgePro is more aesthetically pleasing than the one made with a phone book and two grits of wet/dry paper even though the performance may be identical.

 

[frugalweaver]

Convex ground knives have been proven to be stronger, sharper and easier to maintain if you understand sharpening.

Concave edges are easier to touch up for the novice. Hit the high points and you got it.

Flat is easier to understand then convex and easier to do mechanically.

Begginners and sloppy sharpeners will make an acute convex edge that is not sharp and so think that flat or concave must be correct.

Edge finish is often overlooked. I had a guy try to argue with me that his knife sharpened on 120 grit sandpaper was sharper than my razor honed polished edge. His proof was cutting a 1/2 inch rope in a half dozen saw cuts.
I just shook my head and walked away. Some people don't want to learn. No point in casting pearls.

 

[db]

Thom, I've tried and used every system I could get my hands on.
Lansky, gatco, DMT clamp and rod, Razor edge clamps, Sharpmaker, and 2 other V type sharpeners.I haven't used an EdgePro and wouldn't mind trying one at some time but cann't see getting one just to try it. I also have a 1x30 belt sander and will use it to sharpen but I really prefer hand sharpening on bench hones. Keeping an edge looking like the factory edge is a real good point and I can resharpen by hand to keep that profile if I have too. to me the edges I put on are much sharper than any factory edge and I think they are better looking also. However, a large convex edge probably doesn't look right on all knives. A small well done hand edge looks just the same for the most part as a flat jigged edge. I'm too the point in my sharpening that I can get them pretty as well as sharp.

 

[HoB]

Sharp Thoughts, my sad rip-off of Deep Thoughts. This is my opinion on angle control and sharpness. I dare say that holding a perfect angle is way over blown. In fact I don’t think it really matters much at all. A swing of 1 or 2 degrees either way from a predetermined angle doesn’t matter as long as you don’t raise the sloppiest stroke higher than the angle you want. For example you want a 17 degree edge stroking between 15 and 17 degrees will give you just as sharp an edge as a perfect 17 degree bevel. Maybe even a little better, as the15/17 edge bevel is really kind of a convex bevel. I personally even hold my angles much sloppier than that, witch produces a large shallow convex edge. I just make sure I don’t raise the spine more than I want the edge angle to be. I do all of this on bench hones free hand. So to me angle control really doesn’t mean much to me more important is thickness of the edge and edge finish. Thoughts? Comments? Do you think I’m nuts?
This has been Sharp thoughts by db the angle control troll.

Yup, you got it! :thumbup:

 

[thombrogan]

to me the edges I put on are much sharper than any factory edge and I think they are better looking also. However, a large convex edge probably doesn't look right on all knives.

Thanks for your answer, db!

If more knives left their respective shops with thin-enough blade profiles, they wouldn't have large convex edges when sharpened for actual cutting. Putting the knife to the hone with only a hair's clearance between the spine of the knife and the hone would raise a burr on the opposite side in one or two passes of a fine, ceramic stone and leave an edge that'd be 0.02mm thick at its fattest section. I'm sick of hearing someone say I'm taking too much metal off of a blade when way too much was left on in the first place.

 

[Nosmo]

I'm sick of hearing someone say I'm taking too much metal off of a blade when way too much was left on in the first place.

This is becoming more and more of a problem. I recently purchased a custom in S30v and it's edge had a 17 degree angle. However the thickness of the steel just behind this edge was over 1/16th of an inch. Needless to say it would not cut anything and needed allot of work.

 

[louisianacook]

Ditto Nosmo. The recent S30V custom I acquired had a 14 degree bevel that was about 5mm wide. After hrs. of work thinning the blade, I recently placed another 14 deg. angle on it, this time it was only ~1/16 of an inch wide. Of course, now it cuts well too!


A blade with a great relief grind will contine to cut very well even after the actual edge has started to decline a bit.

Lee

 

[Cliff Stamp]

This is becoming more and more of a problem. I recently purchased a custom in S30v and it's edge had a 17 degree angle. However the thickness of the steel just behind this edge was over 1/16th of an inch. Needless to say it would not cut anything and needed allot of work.

This is a common "tactical" profile, mainly due to using unsuitable steels which simply don't have the necessary durabilty which force heavy profiles.

However, a large convex edge probably doesn't look right on all knives.

It doesn't look right on any knife unless you need it to function as a splitting wedge thus it has a place on some chopping blades which need to force materials apart violently as otherwise they will bind. Aside from that consideration, the edge profile should be minimal in both thickness and width as the force is concentrated at the edge. As Thom noted, wide bevels are mainly a side effect of too thick edges, use a more optimal primary grind. There is no need to be sharpening a wide strip of steel, only a few thousands is actually cutting anything.

Really enjoy reading your reviews. It's great to see someone putting as much work as you do into objective testing. Keep up the good work.

Thanks, I was talking to Matt Lamey awhile back, really like the looks of the Fikes style blades has has done. Though I find cord wraps abrasive in extended use, guess I need to do more work.

Concave edges are easier to touch up for the novice.

I don't think you can produce a concave edge by hand, hollow primary grinds are easier for anyone to sharpen as there is less metal to remove and in extremes basically have included angle jigs. They are better than convex blades at somethings (slicing cardboard) but not at others (deep cuts in woods). I think you could argue convex edges are superior in general, but in some applications the optimal curvture is so shallow it is basically flat and a multi-bevel flat profile is very competitive and much easier to apply.

I had a guy try to argue with me that his knife sharpened on 120 grit sandpaper was sharper than my razor honed polished edge. His proof was cutting a 1/2 inch rope in a half dozen saw cuts.

For slicing it requires less force, or takes less edge with the same force. It will also cut for far longer. I don't see how you could not call it sharper. Sharpness for push cuts and slices are at odds in terms of optimal grit finish. Many makers will go somewhere inbetween, the fine india hone is really popular with a lot of makers as it has enough aggression to still slice well but doesn't hold up on fine push cuts.

-Cliff

 

[G3]

My Downs has been my "Eleanor" when it comes to sharpening. The blade is hollow ground with a convex edge and is a spearpoint shape. The first sharpening attempts were hideous and unproductive. Upon learning the nature of convex vs. flat grinds, I am now able to sharpen it to a razor on the sharpmakers and then strop with jeans for a fine polished edge that has easily become the sharpest in the house. It's definitely a different animal to get accustomed to. I've had people tell me "it doesnt feel that sharp" until I tell them they are angling it wrong and the "ooos and aaas" start again.

Something I do different when sharpening a convex edge is instead of slicing down, I pull up and away. Doing that first a few passes, then 1 or 2 down normally, then stropping. When stropping I pull the blade flat and arc up at the last second but before I'm done I will reverse the direction and slice flat into the strop. This seems to almost roughen up the edge a bit and then a few more regular passes and is good. Not only is this a razor for slicing (though not as flat an angle as a flat grind) but push cutting is a breeze and holds egde better than my flat grinds.

Does this sound right? ;>)

 

[HoB]

My Downs has been my "Eleanor" when it comes to sharpening.

It has taken you literally over edge, if not over a bridge, mmmh? . I love that movie, not to mention that car.

It seems that convex grinds that can be sharpened on a Sharpmaker have intrinsically a pretty decent edge and blade geometry. Since on a convex edge the angle increases towards the edge and since you are able to sharpen it on the Sharpmaker, the angle at the very edge must be <20 deg. That means that the blade width behind the edge must be fairly small, since the angle decreases quickly as you move away from the edge

 

[G3]

Yes that appears true. After a few sharpenings I reprofiled the back bevel and made it just slightly thicker than the edge. That was a PITA tho and I could only do it freehand but it's kind of a ZEN thing.

 

[db]

&#8220;
Cliff said&#8230;
Originally Posted by db
However, a large convex edge probably doesn't look right on all knives.

It doesn't look right on any knife unless you need it to function as a splitting wedge thus it has a place on some chopping blades which need to force materials
apart violently as otherwise they will bind. Aside from that consideration, the edge profile should be minimal in both thickness and width as the force
is concentrated at the edge. As Thom noted, wide bevels are mainly a side effect of too thick edges, use a more optimal primary grind. There is no need
to be sharpening a wide strip of steel, only a few thousands is actually cutting anything.

I&#8217;m not a knife maker nor do I get a lot of customs. I agree with Thom there are way too few of choices of blades with nicely thin blade grinds. I work with what I have, mostly production blades, and by hand sharpening and thinning the knives I have I end up with a pretty wide convex edge bevel. It&#8217;s just the result I get by thinning it by hand with a bench hone. If the blade grinds were thinner the bevels would be smaller. The reason I put convex edges on is because I am doing it by hand and it&#8217;s easy to do. I also like the look, no edge bevel shoulders. If I were making knives I&#8217;d probably do things differently and as I&#8217;m still learning I&#8217;ll probably change what I do now but who knows. I really like the results I&#8217;m getting with my hand sharpening and it&#8217;s a big improvement from my jig sharpening days. I&#8217;m glad I&#8217;m past the angle control crutch.

 

[frugalweaver]

I would not argue either way. Just making an obsevation. Most beginners think concave is better. And you elaborated very well on my statement.





Scratching a blade with 120 grit is almost like making a handsaw. To say that is sharper than a properly shaped and finished edge is a stretch. Everything you said is correct in theory but can be taken to extreme in practice. I believe we are in agreement, I just wanted to clarify that the guy in question was a dufus and in no way had any idea how to sharpen anything.