GEC factory edge vs. reprofiling

fatcorgi

fatcorgi

Joined
Nov 12, 2011
Messages
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I have bought 4 GEC knives so far, and my experience with the edge is that it comes very sharp, but with a very obtuse edge - I would estimate around 50 degrees. My practice up until now is to reprofile them to 30 degrees, or 30 degree backbevel with a 40 degree edge. This is convenient for me, providing a nice sharp edge that is easy to maintain on my sharpmaker and strop.

I started wondering though, if there is some good reason why the GEC people give the blades such an obtuse angle? Is this to give people the freedom to put whatever edge they like on it? or is it actually a good thing to have such an obtuse angle, e.g. is this the sort of edge people would have used in earlier times, before it became necessary to whittle hair ;). I'm wondering if I can maintain this edge with a strop for example, and it will stay sharp for longer by virtue of the thicker edge? Does anyone here leave the factory grinds on their knife and find a way of making it work for EDC. The reason I ask is that I'm expecting 2 more GECs (including the anticipated BF knife) and I think its a pity I'll have to take off so much steel for the reprofiling.
 
fatcorgi said:
I have bought 4 GEC knives so far, and my experience with the edge is that it comes very sharp, but with a very obtuse edge - I would estimate around 50 degrees. My practice up until now is to reprofile them to 30 degrees, or 30 degree backbevel with a 40 degree edge. This is convenient for me, providing a nice sharp edge that is easy to maintain on my sharpmaker and strop.
Click to expand...
I do the same thing.




Kris
 
Yep, same here. They cut SO much better this way, and for the heavy duty stuff there's always a bigger knife available (although most of those have similar angles as well).

But it's a shame that it isn't the other way around, making the factory edge more obtuse would way easier :D
 
I've come to a point where I would be happy to buy a knife with no edge on it at all. I use all my knives and I sharpen them all to my liking (which is subject to change). IMO, the knife maker's job is to temper the steel well and to put the right grind on the knife. The edge is my responsibility.

I think you're right to question both super skinny blades and super polished blades. I think it depends on what you are going to be doing with the knife.
 
I have left the factory edge on a few, and just stropped to maintain. This has eventually rounded the shoulder a bit.

Others I have convexed. On my #23 and #73 I have convexed the clips, and left the spey closer to factory (though I did touch them up on some 600 grit, so they are probably not factory angle any more)
 
It appears that GEC uses wheels to sharpen. This means a hollow grind edge. A hollow grind edge that appears to be close to the same angle as a convex or even flat V edge is going to be weaker.

No matter how you intend to sharpen, you will be losing the original edge grind if you use the knife.

Sharpening on the sharpmaker is in no way shape or form too thin on either of the factory settings IMO.
 
V-Hollow-Convex.jpg


I just drew this up in paint. It is not perfect, but it illustrates the difference between hollow (red), Flat V (blue)and Convex (black) on an edge that may appear to have the same "angle(s)".

I hope this helps.

Kevin
 
GECs and Sharpmakers don't play well together in my house. I try to strop to keep the factory edge, but once it needs to be sharpened, I spend days on the sharpmaker to get it back to slicing like I want.
 
SubSpace said:
GECs and Sharpmakers don't play well together in my house. I try to strop to keep the factory edge, but once it needs to be sharpened, I spend days on the sharpmaker to get it back to slicing like I want.
Click to expand...

Spyderco should start including a sharpie marker with their sharpmakers. From the sounds of it you don't have the right edge established for your sharpmaker if it is taking you days to get it back to sharp.

If you keep the edge up and have it profiled for your sharpmaker then it should not take more than a minute or two to bring an edge back. That is assuming you don't let the edge completely blunt before sharpening.

Something doesn't sound right :)

I just noticed you said the factory edge... That does make sense, but after reprofiling it should not take more than a minute or two.
 
thanks for the info Kevin, that's interesting about the hollow factory grind, which means that a radical reprofile is inevitablly necessary with these knives at some point.
 
You are very welcome and yes, basically, unless you also sharpen with wheels. Wheels are my absolute least preferred method though. The good thing is actually that GEC DOES put a THICK hollow grind so you don't have to start with a thin weak hollow ground edge :)

Also, it seems they use a decent size wheel because the edges are not terribly concaved. With that said, the point of my illustration was to show just what you noticed, along with the resulting strength differences, and edge shape that leads to different cutting performance :)

Edited to add: If you sharpen the factory hollow edge on a flat stone you will still be able to hone the shoulder and very edge and acheive a sharp blade. So an immediate reprofile is not a must. I think the pic helps see that too.
 
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Cool picture, thanks for that P.

I like the wheel my uncle has at his shop. You sit on a seat and pedal it :p

I was almost expecting you were going to post a pic of something like that... knowing your sense of humor and all :)
 
I hate wheels as well. I use one sometimes to quickly reprofile completely dull kitchen knives (not mine, those are sharp :) ), but I find it very difficult to estimate the edge angle on wheels. Probably just a lack of practice.
And since the GEC edges get buffed as well, it would be flat, then hollow and then convex ;) Maybe Kevin can draw another illustration :D
 
Sturzi,

I just took a look at the pics P linked. It looks like they use a buffing wheel of sorts to polish the edge. So in a way it would slightly convex but if they only use it to remove the burr and slightly refine the edge then you will still have a hollow grind.

The GEC's I have all came with grit marks still in tact so I doubt they go overboard polishing off the burr :)

All just assumptions :-p
 
It was meant as a joke, but I'm sure you're right :)
I even found out that I still have one GEC with a factory edge :eek: . Examining it, only the shoulder looks polished and the edge is less affected by the buffing.
 
What you see on yours is what I see on my factory sharp GEC's.

You may have been joking but you are correct IMO :)

If I sharpen a knife on a wheel and then strop on a leather belt on my grinder it WILL end up convex if I just keep stropping.

Like my EDC 85 for example. I sharpen it on a flat benchstone to get it as Flat V as possible and I keep it up for months at a time on various strops. Eventually it becomes a nice convex.

:)
 
Every knife I own I resharpen the day I get it...I have muscle memory for a certain angle and reproduce it on all my knives, its a pretty low angle too (I like an aggressive edge).

That said, the factory grinds were light years ahead of my queens.
 
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