scratch pattern direction

TRfromMT

TRfromMT

Joined
Jan 4, 2016
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I've been studying and working on my sharpening. One topic I am interested in is the specific orientation of the scratch pattern with respect to the quality of the edge. I understand the emphasis on raising a burr and removing it properly at each step. I also understand there are a great number of variable (steel type, sharpening stone type, media, guided versus free hand, etc.).

Let's call a scratch pattern that is exactly perpendicular to the edge, from edge directly to spine, 90°. (I am not talking degrees per side, just the orientation of scratches relative to the edge).

Let's call scratches that run the full length of the edge, parallel, 0°.

I realize that depending on how I use my wicked edge with all the travel across the edge, there is travel along the edge and the scratch pattern is at a diagonal, maybe 45°.

Please share your thoughts on your preferred scratch pattern.

-What do you prefer, 0° (theoretically), 90°, or some diagonal. And why (edge retention later, versus ease of raising and removing a burr)

-Do you change patterns between grits (to make it easier to see if you have the previous scratches removed)?

-Do you change patterns between sharpening strokes to burr removal strokes?

-Do you prefer one specific pattern for toothy edges versus achieving a mirror polish?

Etc.
 
Yes, I believe there is a effect in edge quality based on the scratch pattern. The angle of the pattern the sharpener puts on a edge effects how it cuts. For an example look at saws with various teeth. Some cut on the push, others on the pull (teeth forward others teeth back and others teeth straight) the straight cuts on either push and pull. I think similar effect is created during sharpening. Using a gadget in
the manner the directions state it will be difficult to create anything other than a forward of backward tooth. In free hand any of the 3
can be done. DM
 
I want it to be at 90 degree.
But it is difficult because I need to slide a stone on the blade on Edge Pro.

Edge120.JPG
 
I rake it between 60 and 45° back to facilitate drawing cuts. Push cuts are less catchy.

Initially I adopted this as part of an angle control strategy and continue to use it as it improves slicing aggression on pull cuts.

When working right off the ricasso/plunge line I will use more of a 90° path, but once that stretch is done I revert to more of a rake.

Even when using a guided system that can accommodate true 90° to the edge I still deliberately rake the grind.
 
I prefer a 90 degree scratch pattern off my WE. It seems to give me a combination of push cutting and toothiness for slicing. Now, on lower carbide steels (like S35VN and below) I just do the 45 degree scratch pattern and it performs well that way.
 
i sharpen with 204UF and 302UF only. the edges lose all scratch patterns and become mirror finished.
 
A bit OT:

Tony (TRfromMT), do you have the WE-GO system? If so, what is the thickest stock knife which you have sharpened on it? The Carothers Utility Fighter? Do you have any upgrades or is everything stock on your system? I have a WE120P but I don't like the vice so I'm thinking about splurging on the upgraded vice system or just to look for the Gen 3 Pro. Maybe I'm just a dunce who thinks that extra bells and whistles at an add $$$ will substitute for ineptitude!
 
Like "Heavy Handed", I also have the scratch pattern raked back ~ 45°. This comes naturally with the strokes I use on bench stones, and isn't intended to facilitate a better draw slice, but is just a result from the technique used. Every once in a while I will do 90° scratch pattern.
 
Casinostocks said:
A bit OT:

Tony (TRfromMT), do you have the WE-GO system? If so, what is the thickest stock knife which you have sharpened on it? The Carothers Utility Fighter? Do you have any upgrades or is everything stock on your system? I have a WE120P but I don't like the vice so I'm thinking about splurging on the upgraded vice system or just to look for the Gen 3 Pro. Maybe I'm just a dunce who thinks that extra bells and whistles at an add $$$ will substitute for ineptitude!
Click to expand...

I have the GO Deluxe, which was offered as a package deal for a short time last year. In addition to the GO, it has another set of diamond stones (800/100) and the 5 / 3.5 micron strops. (Maybe only one of these was extra?). To this, I have added 1200/1600 grit ceramic stones.

I have sharpened up to a .200" thick blade, i believe, as well as my various smaller Carothers blades. It will take a 10" blade, no problem.
 
TRfromMT said:
I have the GO Deluxe, which was offered as a package deal for a short time last year. In addition to the GO, it has another set of diamond stones (800/100) and the 5 / 3.5 micron strops. (Maybe only one of these was extra?). To this, I have added 1200/1600 grit ceramic stones.

I have sharpened up to a .200" thick blade, i believe, as well as my various smaller Carothers blades. It will take a 10" blade, no problem.
Click to expand...

OK then, pretty. much the same set up as what I have with the exception of mine having a micro-adjust for the angle adjustment. I also added 1200/1600 plus the lowest level 50/80 (< kinda waste of $ this one). Good to hear that you are having no issue with BL of up to 10" with that standard 8" rod :)
 
HeavyHanded said:
When working right off the ricasso/plunge line I will use more of a 90° path, but once that stretch is done I revert to more of a rake.
Even when using a guided system that can accommodate true 90° to the edge I still deliberately rake the grind.
Click to expand...
When you start your rake movement, which sounds like maybe 2" in front of the ricasso, is this 'Forward toward the tip'? DM
 
David Martin said:
When you start your rake movement, which sounds like maybe 2" in front of the ricasso, is this 'Forward toward the tip'? DM
Click to expand...


It all sweeps back into a draw cut. I've done enough testing, esp on coarse edges to see the value of doing it this way. In fact I've considered reversing it for kitchen knives as I often use a sliding forward cut when chopping slippery stuff on the board.

At the plunge line the pattern actually has a visibly gentle arc to it, as I'm sweeping the edge while keeping the plunge line up to the corner of the stone.
Then I do back and overlay it at 45° for cosmetic purposes and make QC easier. It is tough to ID incomplete grinds and burr removal when the scratch pattern isn't consistent.
 
The rake angle affects the aggression of the cut, and is most noticeable on coarse edges. Scythe blades are always honed from heel to toe to set a positive rake angle relative to the stroke because of this.
 
There really is a saw tooth pattern at the edge. I've read people say that there's no such thing as "teeth" on regular blades, but experience tells me there definitely is.

If you sharpen at 45 degrees one direction, the blade will "catch" on what it's cutting when pulling. Switch to the other 45 and the blade will catch when pushing. You can see and feel this when doing the 3 finger sticky test. It's kind of amazing actually!

I vaguely recall a contest they held over on the chef knifes to go forum a few years ago. It was kind of "who's the best sharpener?". I believe 3 or more people send in blades they hand sharpened and either detailed or videoed their technique. One of the top 2 was a guy that sharpened at 0 degrees. That is, he slid the blade in the direction from heel to tip down the stone. So there would probably be "no teeth" in this blade. It was judged to be one of the best.

Regarding changing the pattern: Crossing over the pattern by switching directions 90 degrees, is a fairly well known method of achieving a higher effective grit from the same stone. All one direction results in a finish of grit N, which crossing over results in a finish of equivalent grit > N. In the straight razor world, this is called "The X Pattern". Straight razor guys tend to want the highest polish possible.

Toothy versus polished: For what I usually cut, I want a coarse, but very sharp (properly deburred) edge. There is ongoing debate over this and you can read many threads about it. CATRA testing seems to suggest that coarse edges last for more cuts. So does my experience.

Brian.
 
All good info. My problem is I don't sharpen frequently enough (only use the sharpmaker to maintenance every so often, maybe "sharpen" a particular blade 2X /year), no real purpose driven testing to prove any one edge style.
 
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I've always tried to generate a rake towards the hilt on single edge blades and a similar rake towards the tip on double edge blades (like my cheap western W77 Boot knife and my Heirloom M3 USMC fighting knife and also the short "false edge" (which isn't false anymore) on my reproduction KaBar), because a rake towards the hilt helps the blade cut on the draw or pulling stroke, while the opposite bias helps the blade cut on the pushing stroke.
I should add I do most of my sharpening with a Lansky clamp and guide and it is hard to not have a rake in one direction or the other mostly due to the small size of the stones.
I have decided I need a bench stone, something 3" wide and 12" long (or larger if I can find one) so I can sharpen without a rake.

There are some blades where I have achieved a 600grit crosshatch on with an 8" hard (black) Arkansas stone. but that stone vanished about the time a friend moved away (out of state) and Disappeared. 10 or 12 years ago...

When I have time I try to do a champfer cut of the "top of the cutting edge" between the cutting edge and the normal surface of the blade
 
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