Recommendation? How Long to Burr when Reprofiling

M

MrHollowWeen

Joined
Apr 10, 2021
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I'm not new to sharpening however I am new to the edge pro. I have my angle set exactly to 20 degrees (using an angle cube with my knife set in place) and am trying to reprofile my Spyderco Paramilitary 2 with the 120 grit stone. I've been going at this thing for a good 15 minutes (not continuous...took a few 30-60 sec breaks to rest my arm) and I don't feel like I'm getting anywhere. My sharpie line still appears on the edge and obviously I'm not getting a burr.

When working on a different knife (with the same steel) I never remember it taking this long with my modified lansky (I modified it a few ways to try to get better performance and accuracy out of it).

I guess I'm just wondering if this is normal on a reprofile and after what time frame I should start to consider that either I'm doing something wrong or there's something wrong with this 120 stone. I have to admit it doesn't feel very "gritty" to me. Could it take as long as 30 arm busting minutes? :mad:

Thanks in advance
 
What type of stone? And what steel on the knife?

At a guess, the stone is probably glazed. I'd think that 120 grit stones should always feel gritty, regardless of type.
 
UncleBoots said:
What type of stone? And what steel on the knife?

At a guess, the stone is probably glazed. I'd think that 120 grit stones should always feel gritty, regardless of type.
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120 edge pro on S30v. As soon as I felt it (upon receiving) I thought it felt glazed. Perhaps you just confirmed my suspicion...
 
Is your stone removing material? From where on the blade is the material being removed?

My first thought is that you're way under 20 degrees. When you set up with your fancy digital cube, are the marks on your EdgePro also indicating that you're somewhere near 20 degrees? Is it a factory edge, or has it been modified?
 
RustyIron said:
Is your stone removing material? From where on the blade is the material being removed?

My first thought is that you're way under 20 degrees. When you set up with your fancy digital cube, are the marks on your EdgePro also indicating that you're somewhere near 20 degrees? Is it a factory edge, or has it been modified?
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The mark is at 21...but yes I'm close to it. It's not a factory edge. When I put black sharpie on the edge and run it for a stroke or 3, it's removed everywhere except right on the blade edge. 15 minutes later, it's STILL not removed from the edge.

Since the sharpening system is new to me and considered to be a better, more precise system I decided to profile to 20 starting with the 120. I assumed I was pretty close going in and therefore would form a burr in a minute or two. But no dice.

I'm probably going to try out the 220 stone just to see if it does anything. That should give me more information about what the state of the 120 stone is. But like I've mentioned, it simply doesn't feel gritty to me at all. It feels incredibly smooth. Too smooth.
 
That sounds like a reasonable course of action. Sometimes an edge is so blunted that you need to remove a lot of material to restore it. And the 220 is also a good idea. 120 is rather course, and it can leave the edge so rough that it might be hard to detect a burr. I've always found that a magnifying loupe in the range of 4x to 25x can be very helpful in determining what's really going on.
 
MrHollowWeen said:
I'm probably going to try out the 220 stone just to see if it does anything. That should give me more information about what the state of the 120 stone is. But like I've mentioned, it simply doesn't feel gritty to me at all. It feels incredibly smooth. Too smooth.
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The 120 stone should NOT feel smooth after dressing. Your "flattening stone" is probably making it worse instead of better. You need to try loose grit on a hard flat surface. If you don't have #60 SiC and don't want to wait try coarse sand.

If Edge Pro is still using the same 220 stone they did ten years ago I cannot recommend you use it as a reference; it is the one stone I found little use for, precisely because it skated it the way your 120 is troubling you now. Dressing briefly helped, but not enough or long enough.
 
Mr.Wizard said:
The 120 stone should NOT feel smooth after dressing. Your "flattening stone" is probably making it worse instead of better. You need to try loose grit on a hard flat surface. If you don't have #60 SiC and don't want to wait try coarse sand.

If Edge Pro is still using the same 220 stone they did ten years ago I cannot recommend you use it as a reference; it is the one stone I found little use for, precisely because it skated it the way your 120 is troubling you now. Dressing briefly helped, but not enough or long enough.
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Interesting...would you possibly recommend "upgrading" to the shapton stones that are "made" for the edge pro?
 
MrHollowWeen said:
Interesting...would you possibly recommend "upgrading" to the shapton stones that are "made" for the edge pro?
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There is an amazing variety of stones available in the Edge Pro form factor. As a Shapton Glass fan, I find it hard to imagine that upgrading to Shaptons would not give you a much better experience, but they are far from the only good option. I like to use diamond or CBN in my guided sharpener, because its role now is precision bevel sets/resets, and the rest I do by hand.
 
I'm not familiar with the edge pro stones being used, are they aluminum oxide?

The reason I ask is almost every aluminum oxide I've used on s30v instantly glazes over and stops cutting. There are a couple with soft enough binder that keeps enough grit released to cut by rolling against the metal, but overall I find alox abrasive miserable to use with s30v and higher vanadium steels.

If they are alox and not releasing grit (not gritty), you can pretty much forget about doing any edge setting with it.
 
Yes, it needs to be SiC grit atleast and not glazed. That model knife could have a thick convex edge bevel. DM
 
If your angle is set correctly it must be the stone. Try taking your 120 and lapping on a lapping plate will help rough it up. If that doesn’t work perhaps it has grease and debris in it clogging the pores of the stone.

Put the stone in a pan, then put it on something to keep it off the bottom, then line pan with degreaser, then VERY hot water will help the degreaser open the pores and lift the debris out. If that doesn’t work, see if they have Silicone carbide stones for the edge pro. I hope you get her all fixed up!
 
Mr.Wizard said:
The Edge Pro 120 uses black silicon carbide.
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All my silicon carbide bench stones handle s30v ok, but a few of them had to be "broken in" before they started cutting well.

I think some of them come out of the molds with a glazed surface that needs to be broken through. It sounds like this might be what the op is experiencing.
Also some just have a hard binder that requires more pressure when using them to keep the surface refreshed.
 
I won't comment on whether or not your stone is glazed or cutting. Presumably you see scratch marks on the edge bevel which tell you something about the cutting action.

Presuming that the stone is actually cutting metal, you might need to do this in two stages. Jason B taught me this in one of his videos several years ago. With a big reprofiling job, it's helpful to drop the angle in two stages. First stage to an in between angle (say 22 or 23 degrees) and the the second stage down to the angle you actually want (20 degrees).

This works better because you can see your progress more easily and thus you can keep the edge bevels the same width as you go. This is much harder to do when you are hogging off so much metal at one time.

Good luck!

Brian.
 
Besides the stone problems which Im sure you will work out once you switch to diamonds ;)

The "Roughing" stage of sharpening is the most difficult and needs to be done cautiously so you don't mess up your knife. Typically, when I start on a new bevel i first grind the edge flat by cutting into the stone. This makes sure you have a more even bevel at the end. The second step is to grind a high angle setting the apex and a basic edge profile, this also acts as a guide for the rest of the sharpening. Lastly, select your angle and start profiling. Just remember to switch sides often, dont grind one side all the way down before switching.
 
I’ve done this 5 times in the past 3 years. Several factors: beginning edge angle and desired final angle, beginning stone, and steel and its hardness.

I did a 5160 knife in about 45 min. Used a 400 grit Naniwa for shaping. Then typical stone progression after the burr was formed. Went from about 19 per side to 17 per side. 5160 isn’t very wear resistant.

3V is a different story. Same process as above but 3V at 60rc. The knife’s bevel was really messed up. Had to cut more steel away. Also went from 20 degrees to 16 or so. I had to stop more frequently to check bevel evenness. This knife took me 2 hours to reprofile. Cuts like a dream now :)
 
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