Edge Pro Form

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Menace

Joined
Feb 1, 2007
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Maybe some of you guys who are more experienced with the edge pro apex can help me out, how do you sharpen knives with a big up swept belly?

For example I'm trying to sharpen my Paramilitary 2, and the following three pictures will show you how I'm holding it on the edge pro's table and I rotate the knife as I follow through with the stroke in order to get all of the blade

starting position

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DSC01021.jpg

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finishing position

Now you can see from this picture, from the sharpie on the edge, that the stone is only getting the entire edge in one spot, it goes from not hitting the edge at all to hitting the entire edge to hitting just the back bevel.

DSC01025.jpg


What am I doing wrong? I've got the angle set at 18 degrees (whatever the green mark is)

Any tips would be appreciated, thanks
 
I sharpen the para 2 by putting the ricasso of the blade on the table, and butting the table up against the G10. Then, you can sharpen most of the blade without moving it at all.

I'll post up some pics when I get home to illustrate what I am saying.
 
I have a professional model Edge Pro and am still learning to use it more effectively but I think I might be able to take a stab (groan) at what you describe. I have other issues due to my Kershaw/ZT addictions meaning that I have a lot of re-curves to deal with. However my Kershaw JYD II offers a similar case of what you are facing.

First of all you might want to consider taking your question to Ben Dale at Edge Pro. Back when I bought my Edge Pro he took phone support calls during some limited hours. Ben invented the thing and is possibly the most patient man I have ever learned something from. He is extremely helpful.

In my opinion it is not that you are doing anything wrong but rather that you have to make a choice about how you want to sharpen the blade and then always do it the same way in the future. More on that later…

It sounds like you are trying to keep the edge of the blade mostly perpendicular to the line of the sharpening stone. I see nothing inherently wrong with that choice but I am guessing that this is your first attempt at sharpening this knife, on the Edge Pro, either since it came from the factory or since whatever other method you may have previously used. What you are doing with the Edge Pro does not match the plane in which the knife was previously sharpened.

With the Paramilitary 2 you have a big flat grind so think of it as a big wedge in geometry terms. You set your sharpening angle at the middle of the blade and in this case you then move the knife keeping the edge relatively perpendicular to the stone. That means that the angle of the stone to the knife edge will be different at each end when compared to the middle. On my JYD II that angle variance would be in the range of .2 to .4 degrees if we go with zero at the blade’s middle. That angle variance is going to vary with the overall angle of the knife grind and to me sounds like enough to do what you are observing.

If you doubt this or cannot visualize it then buy a Wixey brand digital angle measure like used for setting up a miter saw. They are around $30. Set the gauge on a big wedge of wood and zero it like on the center of your knife. Now simulate the twisting of your knife by changing the wedge angle relative to the angle gauge and you will see it. I use the Wixey gauge to setup my Edge Pro when I sharpen knives that are or mostly wedge without any real flat surface to set on the Edge Pro table.

So what do you do about it? You could go down to courser stones (120 the first time?) and slightly alter the existing profile to match and work back up the grits to get a beautiful edge. Don’t jump and do it until more people respond with their thoughts as there is much knowledge on the forum much deeper than mine. It is just one opinion/option.

I would also wait and see what CrimsonTideShooter posts up as what he suggested sounds like it would not move the knife much (or maybe not at all) and depend on the arc of moving the stone to roughly follow the curvature of the blade. Less knife movement is certainly easier on the Edge Pro. Mine has about a 3” platform and your knife blade is 3.44” so little or no blade movement would be possible this way. The closer the arc of the stone versus the arc of the blade the less angle variance you would see over the length of the knife. CrimsonTideShooter’s method might still show some of what you are seeing but possibly less of it if the geometry matches better than your first attempted method. This method could be less work making the edge profile match with your sharpening method.

Note that on some of my blades with high curvature I have observed factory grinds that vary significantly from the middle to the ends so the mismatch could be quite high between using the Edge Pro and the original factory grind. It all depends on what surface plane the factory did it versus what you are trying to do on the Edge Pro.

Ultimately go with whichever makes sense to you and is comfortable to do. Once you settle on the method for this knife stick with it as changing from one method to another will start the same problem all over again. There is only so much steel on the blade for altering the edge profile!

I have enough different knives to sharpen so I keep an inventory and keep sharpening notes for each knife. That way I can maintain nice edges with minimal effort because I keep matching prior methods used. Some knives get sharpened on the Edge Pro, some on DMT Diamond stones and some on the Spyderco Sharpmaker or flat ceramic stones. The one Cold Steel serrated Voyager rescue gets both the Lansky Cold Steel Serration stick and the Edge Pro. Once I pick a method for a given knife I stick with it and that keeps edge maintenance easy.

I can’t wait to see what more experienced folks have to say about this…
 
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to be .... hum brief ... :D

just find a position where your blade is almost centered whith both corners of the blade table and go for it without trying to always keep the edge parallel ...

in more detail: this is a compromise, but i'm pretty sure that after trying your way for some time you'll end up doing this. especially for this kind of blade with a continuous curve, it's not worth the hassle imho. it's different if you have a longer blade or a blade with a long flat edge then a steep belly. not worth it with most spyderco that have a kinda straight/continuous curve.

on my milies i usually put the blade flat on the grind with the ricasso against the blade table's edge with the blade just tilted enough to avoid hitting the other corner of the blade table and i don't move ... if that makes sense.

and when you lay it flat on the grind, keep in mind that the angle shown is not good. for doing about 15° i set the arm at 18°, that's a gross estimation i did once by grinding a spot at 15° with the blade laid on the ricasso then matching the flat spot with the blade on the grind. works for a milie, not sure for a para as i don't own any kid's milie :D:rolleyes:
 
CrimsonTideShooter said:
I sharpen the para 2 by putting the ricasso of the blade on the table, and butting the table up against the G10. Then, you can sharpen most of the blade without moving it at all.

I'll post up some pics when I get home to illustrate what I am saying.
Click to expand...

I understand what you're saying, and if I do that, then I'm assuming the angle markings on the edge pro go out the window correct? And I'd just be matching the factory angle to the best of my abilities?
 
no, the angles are wrong if you lay the blade one the grind like you and i do because on the ricasso the blade is parallel to the table. on the grind it's tilted down to whatever angle the blade is ground at.

just compensate or forget the angle and match the existing bevels.
 
Angle/shmangle. Pwet's first point is most relavent. Just lay the whole blade on the bed. Bump the plunge line into the side of the EP bed. The tip of the Para will come out almost exactly on the other corner. Adjust the guide up until the base of the plunge line is on one corner, and hold the knife so that the tip is on the other corner. Now...do not move the blade. At all. The angle will be within 0.5 degree along the entire edge. That's more than close enough. You will get perfect results if you can do what is said.
 
After the advice offered here and a few exchanged emails with Ben Dale I'm pretty sure i've got it figured out. Set the ricasso up on the table and butted the handle scales up to the edge of the table, set the EP at 18 degrees and went at it with the 120 stone until I had an entirely new bevel on both sides.

Thanks for all the tips
 
Menace said:
After the advice offered here and a few exchanged emails with Ben Dale I'm pretty sure i've got it figured out. Set the ricasso up on the table and butted the handle scales up to the edge of the table, set the EP at 18 degrees and went at it with the 120 stone until I had an entirely new bevel on both sides.

Thanks for all the tips
Click to expand...

Yep! That's pretty much it.
 
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