View Full Version : Advanced Sharpening Notes
Bill Harsey
07-07-2006, 12:41
Just finished hand sharpening some of our knives that have been out in the "sand" made from the CPM S-30V steel.
Two things, first I use WD-40 on the long Norton Fine India stone clamped onto the bench top, this has previously been stated on this forum but it's very important to note this part:
Stop during sharpening to use more WD-40 to clean the abraded particles out of the stone. This is to keep the stone cutting at the best possible "rate of removal".
While we have some WD-40 on the stone, I observed I was watching the little "wave" of the WD moving along just forward of the edge that was in contact with the stone.
Yes I said that correctly, "observed I was watching".
This is how I tell what part of the curved edge is in contact with the stone and let's me know when to stop at the tip so I don't over sharpen or "round off" the point of the blade.
x SF med
07-07-2006, 14:49
Mr Harsey-
When can I take your sharpening class(es)? Your insights amaze me, I can keep a blade fairly sharp, but you make them sing...
The Reaper
07-07-2006, 18:16
This is how I tell what part of the curved edge is in contact with the stone and let's me know when to stop at the tip so I don't over sharpen or "round off" the point of the blade.
That is my problem.
I can get the edge right but I round the tips.
I always have to go back and repoint the tip, which is then uneven.
'Course, I don't have one o' them fancy bench stones.
Got plenty of WD-40 though!
TR
Mr Harsey-
When can I take your sharpening class(es)? Your insights amaze me, I can keep a blade fairly sharp, but you make them sing...
Ditto.
I'm starting to make excuses to my girlfriend why I would have to take a pilgrimage to the Northwest that doesn't involve guns or knives.
Bill, there's some great fishing up there, right?
Bill Harsey
07-08-2006, 08:01
Mr Harsey-
When can I take your sharpening class(es)? Your insights amaze me, I can keep a blade fairly sharp, but you make them sing...
If you get close to this neighborhood, your a welcome guest in the shop and we can work on sharpening.
TR, You need me to find a stone for you?
BrianH, The fishing up here is one reason to keep knives sharp.
TR, You need me to find a stone for you?
I don't know about TR, but THIS GUY needs you to find a stone for him :)
Bill Harsey
07-10-2006, 12:11
The one single stone I use the most for knife work here is made by Norton and is called the Crystolan/India Combo. It's an eleven inch long double sided stone, medium silicon carbide on one side and fine aluminum oxide on the other.
Current price on this stone from Tru Grit is 36.25 US plus shipping.
If you can't get something sharp with this, you need a belt grinder.
Here's the contact: Tru Grit Inc., (trugrit.com) in Ontario, California.
Phone: 909-923-4116
Tru Grit are great folks and are very good to deal with.
They supply all of Chris Reeve Knives and my grinding belts and other abrasives like stones.
Bill Harsey
07-12-2006, 10:32
One of the subtle problems sharpening any knife, especially the thicker tactical or hard use type blades is that we do a whole lot of sharpening and the knife isn't getting sharp.
Sometimes it's tempting to change the angle to make the knife sharpen out to the edge faster. This can be a mistake because it blunts off the leading edge and this makes the knife not cut as well as it could, and makes it harder for us to maintain a sharp knife in the long run.
Try using some magnification to look and see what part of the edge your working on.
Here is my point, often we don't need to change anything we are doing while sharpening but only need to keep doing the same thing a while longer to get very good results.
The Reaper
07-12-2006, 10:53
Bill:
If I could elaborate afrom an amateur perspective, that angle is one of the reasons that I have suggested carefully marking the sharpened portion of the edge with a Sharpie or some other marker to see how much you are taking off and where.
If as you sharpen, you see the color of the marked edge is not being removed uniformly, you are changing the edge geometry.
On a really good knife that comes sharp, the factory edge is probably where it needs to be to do what the blade is designed for. The edge geometry on an axe will not be the same edge as a machete, or a pocket knife, or a straight razor. Most good sharpeners have the ability to change edge angles to suit the design of the individual piece. It might even have a compound angle, or serrations, which can be a real bear to maintain.
Once you have the right angle for sharpening the individual blade, try to maintain it during the remainder of your sharpening.
HTH.
TR
Advance sharpening notes......................hell, now you reallly want me to hurt myself.
Bill Harsey
07-12-2006, 13:24
TR,
Your correct about using the magic marker on the edge, this does help.
When sharpening I stop and look for the fresh abrasion marks and have gotten used to "reading" those.
Bam Bam, just trying to help.
The old saying "a dull knife will hurt you worse than a sharp one" wasn't penned by anyone around this shop.
inbredyokel
07-12-2006, 19:31
...sounding completely bone (dumb), I use a kitchen devil for knives and on my multitool...it doesn't get a knife or blade razors enough for shaving, but its certainly good enough for government work, and it takes ten seconds to use.
Or would that be like cheating or something?
I'm all for the easy option...
Harsey here, "Lightly edited by me for the delicate ears that may inhabit this place".
Bill Harsey
07-12-2006, 19:43
[QUOTE=inbredyokel]...sounding completely bone (dumb), I use a kitchen devil for knives and on my multitool...it doesn't get a knife or blade razors enough for shaving, but its certainly good enough for government work, and it takes ten seconds to use.
Or would that be like cheating or something?
I'm all for the easy option...
Good Sir, What is the Kitchen Devil? I may have some thoughts on this.
inbredyokel
07-12-2006, 20:12
Its a small knife sharpener I bought in a supermarket from the area that girls buy all of their recreational toys from- you know where you find the rolling pins, irons, cooking utensils and the like.
It has a small U shaped plastic handle with two metal spokes in a cruciform at its top.
It looks a bit like this:
X
U
Hold in left hand, place knife in the point where the metal spokes cross and pull across till satisfied.
I've never had to use more than a few steady strong wrist actions to achieve a good end result. :)
Bill Harsey
07-13-2006, 09:18
inbredyokel,
I found it via Google. If I'm reading correctly, the actual sharpening surface of the sticks are steel(s)?
Those look good for light touch up work on thin ground blades.
I received my Tru Grit Norton stone, tried your WD-40 "observation trick", and I'll be damned if I didn't put the sharpest edge on my Strider BT that I've ever felt. I'm almost afraid to have it out of the sheath.
In other news, I can't WAIT for my micarta Sebenza to come in the mail. Now if I could only justify to my girlfriend that I absolutely NEED that Lonewolf D2...
Bill Harsey
07-14-2006, 07:35
I received my Tru Grit Norton stone, tried your WD-40 "observation trick", and I'll be damned if I didn't put the sharpest edge on my Strider BT that I've ever felt. I'm almost afraid to have it out of the sheath.
In other news, I can't WAIT for my micarta Sebenza to come in the mail. Now if I could only justify to my girlfriend that I absolutely NEED that Lonewolf D2...
Good job on the sharpening.
Your on your own with the girlfriend.
Prester John
07-15-2006, 10:03
That's why I got rid of mine... girlfriend that is.
BrianH,
Don't you mean MY Strider BT? Thanks for working on it and all. I hope I can re-claim my room and possesions when I return from leave.
Bill Harsey
07-16-2006, 10:42
The type of edge that comes off the Norton Fine India stone (as previously described by me in this thread) has been proven, in both field and bench testing to last the longest in hard knife work. Let me explain why I say this:
This is not just my opinion but the result of extensive field testing by some very experienced hunters using knives in Africa, Australia and all over North America who then bring their observations back to us in our "group".
This "group" I work with for knife testing consists of two American Master Blade smiths, a senior scientist/knifemaker from Lawrence Livermore National Laboratories and one of those hunters described above plus Chris Reeve and myself. We also have a couple of those Crucible Steel metallurgists around in case we have a question. This is far from a mutual admiration society.
This "group" meets once a year for a formal presentation and works together year around on heat treating, edge geometry and sharpening. We have done so for over a decade now.
If we can't get the sharpening right, there is no way to test and compare different alloys of steel and focus on the optimum heat treat. We have learned there is a direct relation to the sharpness of cut, grain size and type of the grit in the sharpening stone that makes a knife cut aggressively and hold it's edge as long as possible.
The Norton Fine India is the standard we use for all field and bench testing work because the edge that results from correctly using this stone is the best we've found.