What does it mean to reprofile a blade?

D

Dr sharp

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Oct 20, 2003
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Ive heard alot of talk about reprofiling a blade and also blade profile. What does this mean? Thanks guys.
 
To reprofile a knife is to change the angle or angles of its bevel(s) to change its performance characteristics.
 
shao.fu.tzer said:
To reprofile a knife is to change the angle or angles of its bevel(s) to change its performance characteristics.
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What he said. Normally it implies thinning out the edge bevel to improve cutting performance. Too many knives come with very thick and obtuse edge bevels; that may make them tough, but it certainly hurts the cutting performance.
 
Since we're on the subject of reprofiling, does anyone use a Sharpmaker for this? It takes me about 500 passes per side (this is an estimated average) using the corner of the brown stones to achieve a 30 degree edge, on a blade that's developed shoulders from repeated sharpenings at 40 degrees.

Is that about right, or am I doing something wrong?

Thanks.
 
Yep, reprofiling a blade on the Sharpmaker can be a real chore unless you have a set of the the diamond rods. They're a little pricey (62.95@ knifeworks.com) but they really cut down on the time it takes to reprofile or sharpen very dull blades.
 
Boozoo Chavis said:
Yep, reprofiling a blade on the Sharpmaker can be a real chore unless you have a set of the the diamond rods. They're a little pricey (62.95@ knifeworks.com) but they really cut down on the time it takes to reprofile or sharpen very dull blades.
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Someone else on here mentioned taking a diamond hone or a course hone and laying it against the Sharpmaker's 30 degree rod and using it to reprofile it faster.
Sounds like a great idea to me.
 
Sharpmaker - is good for touch-ups. If Blade is really dull - you can use an extra-coarse DMT Stone( I have 220 ) to re-profile the edge - then use Sharpmaker. I got one at amazon.com
 
For the ultimate in re-profiling: EdgePro. Perhaps the most expensive knife sharpening option short of a professional electric system, it really does a nice job getting accurate and repeatable angles on a knife.

I have one here in the desert. It gets used near about everyday. I have a self appointed secondary mission of ensuring that everyone has a sharp-sharp knife. Otherwise, I wouldn't be able to justify the expense.
 
I cut strips of various grip sandpapers, mostly waterproof aluminum-oxide ones, and secure them around a pair of Sharpmaker stones. For that task I use the black triangular heavy duty paper clips. I thin edges down to 30 degrees all the time and hate doing it enough with 120-220 sandpaper (usually go to 400 before the greys), so I couldn't even imagine using just the coarse stones. Mind you, I only use the flats. I like my tips.
 
Yes, reprofiling is changing the angle at which the secondary bevel is ground, in order to achieve a different cutting characteristic.

I sharpen and reprofile my blades freehand. :)
 
puukkoman said:
Yes, reprofiling is changing the angle at which the secondary bevel is ground, in order to achieve a different cutting characteristic.

I sharpen and reprofile my blades freehand. :)
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I use the sharpmaker and also do it semi-freehand since I reprofile between 30 and 40 and flat side it at 40. I guess my knives haven't been that bad because it doesn't take me that long to reprofile on the sharpmaker.

I do clean the stones about halfway through or when switching to the fines.
 
Reprofiling is changing the angle of the back bevel angle on the blade. Most blades are sharpened with two bevel angles on each side of the blade. The back bevel angle will be at about 15 degrees per side (30 total) and the primary micro-bevel edge which is very small at the very bottom edge of the blade will be at 20 degrees (40 total).

Here is a link that shows the concepts with good pictures and drawings. As already mentioned, most knives are sharpened with two bevel angles on each side. The bottom primary micro-bevel edge should always be at an angle that is greater than the much larger back bevel.

For instance. You can change the back bevel from 30 degrees total (15 per side) to 24 degrees total (12 per side). Then you finish sharpening the primary micro-bevel edge at 15 degrees per side or slightly more than the primary edge.

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

The smaller the angles the better the knife should cut but you can only go so small before the edge fails. The knives with better steels can usually be sharpened to the smallest angles.

Our resident guru wizard jedi knife master, Mr. Joe Talmadge, has a great post on the "Toolshed forum" of KnifeForums.

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

This is the place to go for knife sharpening questions and comments.
 
MikeV said:
Someone else on here mentioned taking a diamond hone or a course hone and laying it against the Sharpmaker's 30 degree rod and using it to reprofile it faster.
Sounds like a great idea to me.
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That is what I do. A course stone and a Sharpmaker work great for reprofiling. I have heard that some people also wrap the stones with a course grit of sandpaper for reprofiling. Haven't tried it yet, but I have been thinking it would work great for reprofiling recurve shaped blades.
 
MikeV said:
Someone else on here mentioned taking a diamond hone or a course hone and laying it against the Sharpmaker's 30 degree rod and using it to reprofile it faster.
Sounds like a great idea to me.
Click to expand...

Sumptin like this:
http://www.g3l33m.com/knives/theTable.htm

I was finishing the tip on my Basic 9 last night and thought I'd try my 2 x 48 grinder. It worked a little too well and I burnt about 1mm of the tip off.:eek: BUT... it will shave all the way up the blade now.:thumbup: Once I get better with the grinder I think that's how I'll be reprofiling in the future.

oil
 
Artfully Martial said:
What does it mean to reprofile a blade?

Well, it means something different and special to every one of us.
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I have a feeling that is a little more philisophical an answer than he was looking for.:D
 
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Since people here like to split hairs- Generally speaking, "reprofiling" means changing the shape of a blade. In the commonest conception it would mean changing the outer lines of the blade shape. When referring to changing the sharpening angles, many people here use the term "reprofiling."
Bill
 
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