Faceted edge with DMT Aligner...

D

dillon_b12

Joined
Dec 23, 2009
Messages
242
It seems like no matter what I do, I just can't get a consistent looking finish with my DMT Aligner stones.

I made a holder to use the stones free hand. I'm getting edges that are just as nice if not better than what I was getting from the aligner, but I'm still struggling to get an even appearing edge.

I tried to take pictures of the edge bevel, but can't seem to get them to show what I'm talking about.

My set has the EC,C,F, and EF stones. Once I get to the green EF stone, the edge gets VERY sharp, but is no longer one even finish. It now has what I can only describe as "facets". It's not necessarily the free-handing, since I was having this same problem when using the stones with the Aligner clamp setup.

Has anyone else had this problem?
 
The only thing that makes any sense as far as the facets would be inconsistency in the angle at which you are holding the knife while you're sharpening, but that shouldn't happen with the aligner. Not sure what else it could be.
 
As far as I know the stones are broken in. I've probably sharpened 20 times with them.

I would think angle inconsistency would show up as an unevenly sharp edge?
 
Two questions for you, are you repositioning the clamp during sharpening this would explain it as the angle would change the slightest bit giving two distinct angles on the same side.

Do you sharpen in in one continuous motion from tang to tip or do you sharpen the straighter part of the blade first and then sharpening the curved part to the tip seperately, this also would cause a faceted look.
 
No, not repositioning the clamp. Also, it doesn't have two distinctly different angles. It's like there are 1,000 different angles, creating a faceted look.

When I'm sharpening, whether it's with the Aligner or freehand with the stones that come with the Aligner setup, I either run the edge back and forth as I slowly work my way from heel to tip or I do a sweeping motion that runs from heel to tip in one stroke.
 
dillon_b12 said:
No, not repositioning the clamp. Also, it doesn't have two distinctly different angles. It's like there are 1,000 different angles, creating a faceted look.

When I'm sharpening, whether it's with the Aligner or freehand with the stones that come with the Aligner setup, I either run the edge back and forth as I slowly work my way from heel to tip or I do a sweeping motion that runs from heel to tip in one stroke.
Click to expand...

Ok that blows my theory out of the water, I had a different image in my head, pictures of some kind might still help.
 
What you are seeing is normal and how all edges look to some degree. We'll start with freehand. When freehand sharpening the best you will likely be able to do is 3 degrees of angle change throughout the process, and that would be EXCELLENT angle control. because of this and the fact that the stone can only contact 1 point at 1 time you end up with many grind lines from shoulder to edge apex. Your point of contact in freehand sharpening is usually (with finer stones) about 1/10th the width of the bevel.

When freehand sharpening it is key to use a increasing number of strokes as the stones become finer to blend all of the tiny grind lines you make. Reducing pressure also helps with this blending process as it starts to remove the high points in the multiple lines. You must learn to use you inability as a human to hold a perfect angle to your advantage.

Using even sweeping strokes from heel to tip will create a cleaner and more even edge. When you use small back and forth strokes as you move down the edge you will increase the amounts of "facetes" and high and low points in your bevel. It is also much much harder to make the edge sharp this way.

Bevel appearance when using the aligner will be much better but because the angle guide arms are plastic they flex. This very small flex in the arms allows the hones to contact the bevel at slightly different angles. The amount of angle change will greatly depend on the pressure you use when sharpening with this tool.
 
knifenut,

Thanks for the input. Glad to know I'm not going crazy here. I've all but stopped using the Aligner since I'm enjoying freehand more. I also think, despite it being a "guided" system, the Aligner has some flaws that can cause it to not hold a consistent angle.

Can steel make a difference in this as well? I haven't noticed this effect as much on Benchmade's 154CM or Kershaw's 13C27 as much as I have on my Tenacious (8Cr13MoV).

How would you describe the finish one could expect to see when finishing with the DMT EF?
 
dillon_b12 said:
No, not repositioning the clamp. Also, it doesn't have two distinctly different angles. It's like there are 1,000 different angles, creating a faceted look.

When I'm sharpening, whether it's with the Aligner or freehand with the stones that come with the Aligner setup, I either run the edge back and forth as I slowly work my way from heel to tip or I do a sweeping motion that runs from heel to tip in one stroke.
Click to expand...

I've seen the same issue, when using other clamped/guided setups (Lansky, Gatco). I'm learning that the uneven or 'faceted' look has a lot to do with the consistency and fluidity of the sharpening strokes, from beginning to finish. Alternately changing the type or direction of the strokes (from back/forth, to sweeping the length of the edge, and back) contributes to the uneven finish. Another big contributor to the problem, was varying the pressure used. It's worse when too much pressure is used, and will get still worse as fatigue sets in (leads to sloppiness in all things).

When I sharpen free-hand, my stroke is usually more consistent (I draw the edge down & across the hone, from ricasso to tip). So, the resulting scratch patterns look more uniform.

With the guided sharpener, I'd focus on using one stroke type only, and sticking with it, from beginning through the finish (I think a sweeping stroke is best, especially in the medium & finishing stages). And ALWAYS keep the pressure very light.
 
I had some free time tonight, so I worked on the edge of my Tenacious freehand with the DMT Aligner stones. I don't think I really got much closer to a mirror finish, but I did achieve a level of sharpness that I've personally never reached before.

SDC11166-1.jpg
 
for an even appearing edge, don't use too much pressure when sharpening. make sure you wet the stone using water or oil. baby oil works like charm for me, as does water.
 
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