Yet another sharpening question

craigz

craigz

Joined
Jan 18, 2000
Messages
386
I've been reading John Juranitch's book, I've read Joe T's sharpening FAQ, and now I've been searching for sharpening threads here. I've only been shapening the primary bevel on my knives thus far, and I'm trying to understand the process of reprofiling the blade. Here's how I'm understanding it right now. Someone please correct me if I'm mistaken in the following statements.

1. Juranitch recommends reprofiling a blade into two bevels, a primary and a secondary, where the primary is the actual cutting edge and the secondary is a shallower angle that runs all the way from the primary to the spine.

This method presumably obliterates any markings or finishes on the blade and leaves the secondary bevel unpolished and, essentially, all scratched up.

2. Joe T. (among others) recommends creating three bevels, a primary at the edge, a secondary going from the primary part of the way up the blade, and a tertiary bevel which is the original factory grind that runs from the secondary up to the spine. The size of the secondary bevel is, presumably, a matter of personal preference.

3. Joe's "magic marker trick" consists of marking the entire portion of the blade that will be the primary and secondary bevels. You then begin sharpening at the shallower (secondary) angle until the marker is removed from where you want the top of the secondary bevel to begin to the top of what will be the primary bevel, all along the length of the blade. Then you switch to the greater (primary) angle and sharpen until you get a burr on one side, then the other. Then you switch to a finer stone and polish the primary bevel.

4. Some people prefer to sharpen at the shallower (secondary) angle all the way to the edge of the blade, creating a burr on both sides, then switch to the greater angle to create the primary bevel.

Am I on the right track here?
 
That is an excellent overview. One comment, it is common for the angle designations to go the other way. The primary grind ususally refers to the main grind which describes the blade profile. The secondary or edge grind is what defines the edge. If you double bevel the edge then you are putting another third grind on the blade.

As for the techniques, the one that is described by JJ produces the most efficient cutting edge, and the weakest. The doubled beveled edge is slightly behind in cutting ability (how much depends on how you double bevel and what kind of material you are cutting) but increased in durability. It makes no difference to the end result in what order you put on the double bevel, but it is easier (requires less skill) to put on the shoulder angle and finish with the bevel which defines the edge itself.

-Cliff
 
OK craigz, you're a sick puppy just like the rest of us. You need to head on over to Kit's posting 'Go for the rocord' and confess your knife related problems. Go ahead, you'll feel better. A weight just seems to lift off your shoulders.

By the way, it sounds like you're working with either a flat ground blade or maybe a convex grind. A hollow grind would be a real problem with the methods you described. Go ahead and blast me Cliff. I just don't get that technical with my sharpening. I sharpen my knife intil at least 90% of the hair is gone from my edge testing arm. Now, I wonder why the hair's thicker on that one?
confused.gif


------------------
M.Ogg

"It's better to be thought a fool and remain silent, than to open your mouth and remove all doubt"
 
Check out www.handamerica.com for leather hone sets. These hones come with a variety of powdered abrasives, and two honing surfaces for final-finish honing. I use 600-grit first (on the rough-leather surface), followed by 10000 grit chromium oxide (on the fine-leather surface) finish.

After you've used your stones to set the primary taper, use the two-stage leather hone set to set the final-stage taper.

I use these hones to produce outstandingly sharp final edges on my knives. You won't believe the edges you can produce on good knife steel such as ats34 or CarbonV blades until you try it.
 
Bad4u,

Welcome to the forums!

I tried the link, but couldn't pull it up. I'm very interested in what you posted. Can you direct me to the link.

Thanks!

------------------
Frank Norman
Frank's Page
 
What is the name of this book to which you refer, and where can I buy a copy of one?


thanks

matt
 
Max :

A hollow grind would be a real problem with the methods you described.
Click to expand...

Yes. It would take a fair amount of skill to deepen a hollow grind, you could pretty much make a knife yourself if you can do that. You can lower the edge profile, but you can start hitting the back of the hollow grind if it is not deep enough, which is only a cosmetic thing though.

On average though, most hollow grinds I have seen are thinner than flat grinds. This is usually though because they are on different types of knives. Hollow grinds on light utility and hunting knives and flat grinds on large camp / combat knives.

One of the great things about customs of course is that this is never a problem. You simple tell the maker how you want the blade ground and avoid customizing it yourself.

-Cliff
 
The books is called "The Razor Edge Book of Sharpening". John Juranitch of Razor Edge Systems wrote it and I highly recommend it. Joe Talmadge pointed me to it and I will forever be grateful for that. Before Joe's FAQ and the book, all I ever did was dull knives. They do have a website, www.razoredgesystems.com.

------------------
Knowledge without understanding is knowledge wasted.
Understanding without knowledge is a rare gift - but not an impossibility.
For the impossible is always possible through faith. - Bathroom graffiti, gas station, Grey, TN, Dec, 1988

AKTI Member #A000831
 
On a hollow ground blade you usually don't need to reprofile, the hollow itself provides all the relief behind the cutting edge that you need. For me an exception to this is on the older Buck knives. They used to use a modified hollow grind that left a lot of meat behind the edge and then they used too high an angle on their edge grind. I used to have to spend a long time with a coarse hone to get a Buck 110 lockback blade profile thin enough in the working area. Buck finally did some market research and with their new Edge 2000 process have thinned down their blades. It was never necessary to hone the blade back more than 3/16-inch from the edge, so the hollow itself was never marred.

In the last 20 years I have seldom gone whole hog and reprofiled an entire blade. This is something I would do with a blade that is really overly thick in relationship to its width and I want to make it really sharp. On some Solingen daggers I have ground from midline to edge to enhance slashing ability. Sometimes I have hollow ground the blades in the process, usually I have gone for more of a flat taper. In my youth I used to hollow grind narrow-bladed Italian and German switchblades and stilletos. This would allow me to get true razor edges. On straight blades I would usually restore a smooth finish, on serpentine (or kriss) blades I usually didn't.
 
You must log in or register to reply here.
Back
Top