Putting on the Final Edge?

[Tbonz]

I'm interested in hearing how other makers go about putting on the final edge and what their process is to make the blade sharp for the first time. My154 CM blades are hollow ground hunting knives and I grind them to between.015 and .025 with a hardness of aproximately 58RC
I recently read that some makers put the final edge on with a slack belt setup.I've been experimenting with the slack belt approach and would like to learn how others go about using that method. What type belts and grits do you use, the sequence of grits, any information that could help me get started in the right direction and allow me to improve my skills.
I also have been comparing a buffed edge to a non-buffed edge. Do you have a preference for one over the other or does it simply depend on the blades intended use?
One thing I noticed about my final edges is that I tend to get the sharpest edge towards the tip of the knife, how could I get the whole length of the blade that sharp? Is it simply a matter of working at the back more then the front or is their an approach that could help?
Thanks
Tim

[Ray Rogers]

I don't do slack belt sharpening so I can't comment on that, but I can offer an opinion on some of your other points.

Highly polished edges are good if the blade is used for shaving, like skiving leather or actually shaving hair. For cuts where the knife is pushed through a substance rather than drawn such as in some kitchen preparations they also work well. For slicing cuts, especially on hard substances like rope, polished edges often do very poorly. For slicing meat, I prefer an non-polished edge.

You hollow grind your blades and find that they are sharper at the tip than further back on the blade. My guess would be your grind is not even and the blade is actually thicker towards the rear. It is very easy to get the tip of a hollow ground blade thinner than intended. If you are sure that your edge is the same thicknes for its entire length, try checking the thickness just above the edge. This problem can occur if the hollow grind is too high on the blade compared to the diameter of the wheel used ........

[Don Cowles]

I put the edge bevels on my knives using the slack belt, but it is not very "slack". I set the tension as high as I can get it to make the belt pretty tight.

I start with a Norax X65, followed by a X30, and finally a X16. Then I move to a bench stone (mine is a Spyderco ceramic from Brownell's) lubed with varsol.

The final step for me is stropping on a piece of belt leather mounted to a board, and charged with 14,000 grit diamond spray.

[Tbonz]

Thanks for the information, it is very helpfull and appreciated.
The edge thickness is very close to the same, the tip may have been a bit thicker. When you put the final edge on do you grind from the tip to the back or back to tip? I have been going back to tip.
Ray do use a flat platen to apply your final edge? If so, are there any tips that you could share on your technique?
Thanks
Tim

[JeridJohnson]

my final edge depends on what type of grind I did... for a flat grind I will usually put on a secondary edge bevel on the belt grinder.. I would do this against the platen.. would start with a 320 grit belt and move up to 600. I then finish the edge by hand on stones or crook sticks.. I like crook sticks best..

for a convex edge the blade is pretty much sharp prior to even sharpening.. with this grind I simply make a few passes on the crook sticks and it is scary sharp..

I dont like a polished edge.. I like a grainy edge that cuts good..

[JeridJohnson]

p.s.. with the belt traveling downward.. I sharpen the blade edge up.. be very careful when doing this as to not cut into the belt.. especially when using the slack belt..

[Ray Rogers]

Originally Posted by Tbonz

Ray do use a flat platen to apply your final edge? If so, are there any tips that you could share on your technique?

I apply my final edge by hand, the platen is used to set the initial edge only. For the initial edge, I use a Razor's Edge device clamped to the blade to hold the angle steady. A fresh 120 grit belt running very slow is used to do the initial edge. Of course, this also grinds on the Razor's Edge device but with a little practice this can be minimized. I've had to replace it only twice in 5 years.

For the final edge, my choice is the Edge Pro system. This device resembles a Lansky on steroids. It is quite large and sturdy and uses replaceable stones lubricated with water to do the sharpeneing. It can create any edge finish from rough up to a 3000 grit mirror polish. If the initial edge angle isn't quite right, the rough stones will correct it very quickly. This device works well for anything from folder blades to small swords, straight or recurved, hollow or flat grinds, chisel grinds, whatever. I've never tried it on a convex edge so I'm not sure how useful it would be on that edge....

[Tbonz]

Ray,
I'm not familiar with a razor edge device, is this a jig that is sold or something that you devised and built. Is there a site where I could see what this tool looks like?
Tim

[Ray Rogers]

It's made to guide the blade while working on stones. It works with belts too if you have a variable speed grinder, although you do grind the device away a little as you use it this way:

http://razoredgesystems.com/

[SteveS]

Tbonz,

Ray and Don are the 'Man'. I wouldn't even presume to offer better. I'll just tell you what's worked for me:

My platen is designed so I can tilt it back, way back. I put level on it to set the angle of the final bevel. Like this:



Say I want a 17 degree angle (my common one). I tilt it back so it's 17 degrees off level. Then I run the belt backwards.

While holding the ricasso level with the floor, the belt cuts a 17 degree angle.

I grind my blades to an edge thickness of .010 (on average) before sharpening. I made a kitchen knife at .025 once. Way to thick for anything I do. I've taken other knives to almost zero. Depending on the knife that's not too thin (Japanese swords are taken to zero, no secondary bevel).

I go thru these belts:

220
X65
x45 or x30
x15
sometimes x5
leather belt with green chrome
---------------------------------------------------------------
RE: Buffing wheel.

Some masters use the buffer wheel. gotta be real careful. It will remove a handrubbed finish or roll an edge over. I'm not good enough to do it. I use the leather belt.

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RE: " One thing I noticed about my final edges is that I tend to get the sharpest edge towards the tip of the knife,"

I don't know how you are defining sharp, but.... A shallow angle always feels/acts sharper than a deep one. Could be that how ever you are doing it is making a shallow angle at the belly. This happens with those lansky things (angle changes as the distance from the clamp increases). Or the way you are raising the handle as the belly curves.

On sharpening I'll add two points:

*if the edge thickness is consistent, then the width of the bevel should be the same from choil to tip

* The burr you raise with the coarsest belt should be perfectly consistent before moving up the grits.

Steve

[Tbonz]

Ray,
Thanks for pointing me to the Razor Edge Website. After reading your post and checking out their website I decided to purchase one of their kits and a book on sharpening. I plan on working on my blade geometry, final edge and sharpening skills so I can continue to improve the quality of my blades, paticularly their sharpness right now.
Thanks to everyone who shares their knowledge on this forum, it always is a great help.
Tim

[Don Cowles]

I had the pleasure (and the humbling experience) this week of having four George Herron hunters in my shop. A customer sent them to me for sharpening and cleanup. I have learned a great deal from these knives in just a few days.

The absolute key to "sharp" on a hollow-ground blade is a wafer-thin grind at the edge. Herron is a master. The things were a breeze to touch up, and they are scalpels.

To sum up: grind your blades as thin as you can get them before applying the edge bevels. Sharpening will all but take care of itself.

[Fox Creek]

AMEN BROTHER COWLES, AMEN SIR! That is the best short summary of the subject i have ever read. I would add, If I may be permitted, that , assuming correct HT, the difference between a fine "scapel edge" and hEAVY DUTY tactical chopping edge is the difference betwen 20 degree bevel and a 30 degree bevel.