Edge Pro and Sebbie

[Dcon67]

Hi, I recently purchased an Edge Pro Apex sharpener. Before I attempt to sharpen my seb with it, I would like to get as much info as I can from anyone using one of these on their Sebenza. I have already run a search, but nobody gives any specifics other than it works great. What angles did you use? Did you double bevel the edge? How did you compensate for the hollow grind? Etc.... And any other tips before I do this would be appreciated!

 

[MJB]

I use a Pro model to sharpen all my knives, including my Chris Reeve models.

I mark the edge with a Sharpie and take a few light strokes at 20 degrees, then adjust accordingly. On two Sebbies, I ended up at approx. 19 degrees (halfway between 18 & 20)...on a couple others (Large & Small) I ended up at just under 20. It will take a little trial and error, but if you take light strokes with a higher-grit stone, you won't hurt anything. I have found all of my Sebenzas to be between 19 and 20, just as stated in the Sebenza FAQ.

Before starting, I cover both sides of the blade with blue masking tape to within about 1/4" of the edge to avoid scratching. Then I relax my grip and hold the knife (lightly) on the flat part of the blade (not the ground surface). I think "lightly" is the key word here...too much pressure and it tends to roll down onto the ground surface. If your strokes are light, it takes minimal pressure to prevent the blade from moving up and down. A light touch and practice...you'll catch on very quickly. Also, I found that keeping the stones wet helps everything slide with less resistance.

As I work up and down the blade, I just try to maintain the edge roughly perpendicular to the sharpener. I have found that I get more consistency by moving the blade rather than the sharpening arm. Counting the strokes helps me stay even with the two sides.

For my EDC, I spend the extra time to achieve a highly-polished edge which is not as effective at shaving, etc., but it lasts a long time.

You have made a wise purchase. After a short time, you'll be surprised at the quality results...it may even be a little therapeutic, kind of like reloading ammunition...the zen of sharpening and reloading.

Good luck

Mike

 

[alphamaniv]

MJB,

Do you have flat ground sebbies? I only ask because mine is a convex, and I would like to keep it that way. I also have a few Busse knives that are the same, but I really like the edge pro. Convex edges are the only thing holding me back. Thanks

 

[MJB]

On the convex blades it's a little different.

I like the convex edge on one of my Busse knives...I only sharpen the flat side. On the convex side, I use different grits on a leather hone or, in a pinch, 600 grit sandpaper on a mousepad or something soft, being careful not to overdo it. Just touching up the flat side seems to be all it needs most of the time.

On my Sebbies, I never really noticed a convex edge and I just sharpen them flat. I don't think they were convex or it would have taken a long time to reprofile them. When I put ink on the edge, a light stroke takes the ink across the entire edge.

I have a picture from a microscope of a blade that had 3 bevels, creating the illusion (and probably function) of a convex grind. I bet it took a lot of time and care to do it.

How do you do your convex edges? How do folks do them in general?

Mike

 

[MJB]

Never mind the picture, I can't get it to appear.

What's the secret?

Mike

 

[JohnW]

I've used my Edge Pro Apex on a small Sebbie, and MJB has really laid out the method exactly.

However, the Edge Pro will grind away whatever convex edge exists, leaving a flat grind. For some people, this is a good thing. Personally, I prefer a flat grind because it's easier to maintain with exactitude using the Edge Pro.

If you really want to keep the convex edge, either send it back to Chris, or invest in a leather hone.

 

[Dcon67]

So you pin the blade to the table using the small flat area up near the spine instead of letting it rest in the hollow portion?? Hope thats easier than it sounds. Seems it would be very hard to keep the blade steady that way and not have it tilt down when you apply pressure with the stone.

I had also emailed Ben at edge pro, he suggested that I do as you said, hold the blade down tight on the flat, but he suggested I just take a couple swipes with a medium grit stone in one place to set the bevel I wanted, marker it, and then re-set the angle of the Edge Pro so it matches that bevel I just set with the knife laying on the hollow so that the edge is supported by the table. - but it would seem to me that as you move the knife the angle is going to change due to the shape of the hollow.

I think I am going to try it your way MJB seems the bevel will be more consistant if I can hold the knife steady on the flat although it will take longer since I won't be able to apply much pressure with the stone and I need to fix a factory bevel issue. The bevel came wider on one side than the other, I think its because as it was originally sharpened, they ground more of the blade to create the first burr, and didn't need to grind as much to get the burr when it was flipped.

Alphamaniv - On flat ground Sebs, I think the flat part only applies to grind of the sides of the blade, I think the edge itself is still convex as it comes from CRK, a convex edge is just what you get when you sharpen on a slack belt. How do you keep your convex blades sharp?? Even if you use a sharpmaker, you are grinding the convex edge into a flat V grind. To keep it convex you have to sharpen on a soft surface, or you have to roll the blade as you sharpen on a hard surface (i.e. stones or ceramics). It must take years of practice to be able to do that on a stone by hand and get it right. Has anyone seen buzzbaits page on convex edges?? He says to sharpen them with wet/dry sandpaper and a mousepad! Heres the link if your interested.

Convex Edge

Mike, If you email me your pic of the triple bevel I will post it.

 

[OwenM]

Originally posted by MJB
I have a picture from a microscope of a blade that had 3 bevels, creating the illusion (and probably function) of a convex grind. I bet it took a lot of time and care to do it.

You can do that pretty easily with the EdgePro. Two different ways to do it, depending on how thin you want the edge. Joe Talmadge's past posts about back bevelling got me experimenting with it awhile back.
You can grind the entire edge at a lower angle, then raise the angle enough to make a smaller bevel on top of the first one, then again at an even higher angle for the final edge. That way you can have a "traditional" angle (say 40* included) at the very edge that is easy to touch up with something like the Sharpmaker, while dramatically increasing cutting ability because of the material you've removed behind the edge. IIRC, this is what Joe did when he wrote about maximizing the performance of the BM 710.
Another way is to grind the entire edge at, for example, 40* included, and then lower the angle enough to break the "shoulder" of the edge bevel, then lower it again to blend it in to the primary grind.
Both ways give you less material behind the edge for improved performance. The first is the thinner of the two, since you've removed more material, and cuts "best", the second leaves an edge that is stronger, and has more support. Both are easier to touch up, because you've decreased the width of the final bevel, and both cut better, because you've decreased the resistance of the cut.
I mirror polish the back bevels, but vary the grit of the final edge depending on what the knife is used for, because the very edge is what does the cutting. Everything behind it just creates drag.
Either way makes for a wider edge bevel overall, and may not be very appealing, cosmetically, but it can make a big difference in how well your knife cuts.

I don't know that I'd fool with this on a thin hollow grind like the Sebenza, since it already has a convex edge with great geometry, but I do it on alot of flat ground blades.

 

[Dcon67]

Here is that Triple Bevel pic of Mikes's from above.

 

[Cliff Stamp]

Dcon67 :

[convex edges]

or you have to roll the blade as you sharpen on a hard surface (i.e. stones or ceramics). It must take years of practice to be able to do that on a stone by hand and get it right

I thought the same thing until I tried it. I found it actually a lot easier than matching an angle on a v-bevel. Most of my convex edges are very wide though which makes it easier as it gives more feedback and visual clues. I sharpen them all with a couple of small waterstones .

-Cliff