Re-profiling or Touch up

[soldierofchrist35]

I hear the terms "re-profiling" and "touch up" all the time but i really don't know what is meant. When would I know that my blade needs re-profiling versus just a touch up?

 

[Tim the Wizard]

To me, reprofiling means changing the edge geometry of the blade.

For example, if I receive a blade with a 50 degree inclusive angle (both sides together sum to 50), and then I proceed to remove enough steel to make it a 40 degree inclusive edge, I have reprofiled the knife.

However, if I hone the 50 degree edge with a ceramic, or if I remove a burr at 50 degrees or polish the edge using successive higher grit stones, then I have touched up the edge.

An edge angle cannot be made more acute (lower degrees) without reprofiling, read: removing metal from the primary bevel to thin the knife and make a new edge.

Your blade might need reprofiling if your edge is too obtuse for your needs, or if the edge is chipped.

Your blade might need touching up if use over time has made the edge dull from rolling or if there are microchips, or if you would like to polish the edge after time, but you are otherwise happy with the edge.

 

[Bobby3326]

Yup that about sums it up..

If you buy a knife that has a thick obtuse edge ( 25°+ per side) and it doesn't cut like you would like it too bc of that then you'd need to reprofile the edge to a more acute angle to cut better. (15°-20° per side). Or you could possibly have a knife with a acute factory edge that isn't holding up to your intended use and chips or rolls easily. Then you'd need to reprofile it to a higher angle to withstand your use.

If your knife is sharp, and performs to your liking but is slowly losing its sharpness thru use then you'd need to just touch it up at the current edge angle and hone it back to peak sharpness.

 

[Spartan00]

After so many sharpenings your bevel will start to get thicker as well. You will need to reprofile it or have someone do it if you don't feel comfortable.

What I do is I will reprofile a knife if I am going to carry it . I usually go for a pretty acute bevel . If for whatever reason that acute bevel doesn't hold up to my use then I will put a microbevel on it .

Let me explain it a little better. My emerson super commander came to me with about a 25 degree bevel on it. I reprofiled the bevel to around 15 degrees per side. That bevel is so narrow on the knife though I sharpened just the very edge to about 20 degrees to give it a little bit of strength. This way I get the benefit of having less metal behind the edge ,but I have more strength to my edge because the actual edge is more obtuse than the bevel.

 

[soldierofchrist35]

So if I have a brand new folding knife with Elmax steel and I use it for nothing more aggressive than cutting some thick cardboard, a the point that it will no longer easily slice printer paper, shouldn't that just be a touchup job that can be done on any simple sharpening system (unless i just don't like the angel of the bevel and want to re-profile it)?

 

[soldierofchrist35]

Sorry, I meant the "angle" of the bevel. Not sure what the "angel" of the bevel is....

 

[Obsessed with Edges]

So if I have a brand new folding knife with Elmax steel and I use it for nothing more aggressive than cutting some thick cardboard, a the point that it will no longer easily slice printer paper, shouldn't that just be a touchup job that can be done on any simple sharpening system (unless i just don't like the angel of the bevel and want to re-profile it)?

Most of the time, it shouldn't be a problem to just 'touch up' the edge relatively simply, as you've described; especially on a newer knife with some light edge wear. You'll eventually know when it needs more work, after more use and more sharpenings. With repeated 'touch up' sharpening, the edge will gradually retreat into the thicker steel as mentioned earlier, and you'll notice it may not quite come fully back to the same performance without reprofiling the full edge.


David

 

[Bobby3326]

So if I have a brand new folding knife with Elmax steel and I use it for nothing more aggressive than cutting some thick cardboard, a the point that it will no longer easily slice printer paper, shouldn't that just be a touchup job that can be done on any simple sharpening system (unless i just don't like the angel of the bevel and want to re-profile it)?

Yes if you're content with its current performance and it's just begun to dull then you'll need to touch up the edge to bring it back to its original sharpness...however if you've let it go completely dull then you'll need to spend more time actually sharpening it to get a fresh apex.

I view touch ups as my routine maintenance to keep a knife sharp, once it gets to the point touch ups no longer bring the edge back then a full sharpening is required, after many full sharpening sessions the edge will begin to thicken up. This will hinder the knives original performance, and a reprofile is needed to thin down the edge and bring it back to its original state...

Now after many many many rotations thru this cycle and as the edge gets sharpened back you'll reach a point where the knife will need a regrind, which is where the the entire knife is thinned down to compensate for the edge loss over many many sharpenings... This scenario is unlikely for the average user however, unless it's 20 years from now...but if you're a heavy user and sharpening weekly then this scenario could present itself in a year or 2.

 

[Tim the Wizard]

This is an excellent way to hone a knife:

[video=youtube;Z2-fBy-4CpI]https://www.youtube.com/watch?v=Z2-fBy-4CpI[/video]

With a ceramic and a strop, you can keep a nice edge going for a very long time, short of any major chipping or tip damage.

 

[cbwx34]

So if I have a brand new folding knife with Elmax steel and I use it for nothing more aggressive than cutting some thick cardboard, a the point that it will no longer easily slice printer paper, shouldn't that just be a touchup job that can be done on any simple sharpening system (unless i just don't like the angel of the bevel and want to re-profile it)?

It should be, except for this...

... many knives from the factory come with one (sometimes both) side buffed at a higher angle to remove the burr. So when you start what should be a simple touchup, the stone won't contact the very edge, even at a higher angle than what the bevel on the knife is. So you end up with a knife that you don't understand why it won't get sharp again.

Sometimes the buffed angle is so steep, the only way you can tell, is either by magnification, or by a burr that appears on the buffed side (usually pretty noticeable) but not on the opposite side, because it doesn't get "flipped back over" since the stone isn't making contact. Only way to fix it, is to grind it out.