edge pro users, need some advice

It isn't your stones. The 650 may be a few, 2-3, thousandths of an inch thicker than your 1100, which will help. A .01" difference in stone thickness will be fine, .02" will be noticed if everything else is perfectly repeatable. The bigger your bevel the more stone thickness matters. I would guess your angle is changing because the knife apex is moving. Work on keeping the knife in the same spot while you sharpen and flip, consistency is what you are working towards.

 

@hemi1300 ^^

 

Ben has ALWAYS said to take a few strokes, flip, take a few strokes, flip, repeat. I have never heard him say differently in 25 years. He says this is to keep the bevels even. It is my experience that removing the burr with an edge leading pass is the worst thing you can do. It will fold the burr onto the apex which is very fragile and often damage it. Granted you need a microscope to see this but you can feel the difference in sharpness. The Matrix stones will create about the smallest burr of any stone of similar micron rating so I would suggest a couple swipes with a strop to remove the burr. If you load your strop with diamond then limit it to 2-3 passes otherwise you will convex the apex. If you want to keep some toothyness then use a bare strop. With your Matrix stones once you set the bevel you should only need 10-15 passes per stone per 3" of blade length, doesn't matter if you are sharpening decent stainless or Maxamet.

 

Are you referring to an edge-leading pass at a high angle, as Cliff Stamp and others advocate, or are you talking about a guided pass at the bevel angle?

 

Guided pass at bevel angle, and pretty much any edge leading pass once you reach the apex. I first ran into this idea on the Science of Sharp blog then confirmed it with my own trials inspecting the results with my microscope. SOS blog says the keenes of edges can improve up to 10 fold by using edge trailing passes vs edge leading. I even have Ben doing it now so that must be worth something.

 

I also read Science of Sharp but I guess I came to a different conclusion; why not use edge-leading strokes to reduce burr formation, then refine with a few edge-trailing strokes to get that keenness? Compelling that you've got Ben doing it; maybe I'm next.

 

There is specific information about this in two spots on the blog. I will have to find it again so I can say where it is when I reference it. He is quite clear, including nice images, that edge trailing strokes form a keener edge. When I got my microscope working right it completely changed the way I sharpened, I found out a lot of my beliefs were wrong.

With the Matrix stones you don't have to worry as much about burr formation since the burrs are pretty small when used correctly, and even smaller if you use no added pressure on the last few strokes. I use back and forth strokes until I start to apex then use edge trailing only after that. What little burr is left comes off nicely with a few strokes with a leather strop, at the same angle on my guided sharpener.

 

Instead of stropping I usually finish with a 3 and .5 micron diamond lapping film, progressively lighter edge trailing strokes on each side. Leaves the edge looking really nice under a 10x loupe and makes the hairs pop off my forearm.

I'm going to try with the 2300 and 4000 grit matrix stone next time, I expect the results will be similar.

 

Yes, the SEM images make that clear indeed. What kind of microscope are you using; oil immersion optical? Were any of the wrong beliefs something you will talk about? I wonder if I still hold them.

Got it! For some reason I had the misapprehension that you were using only edge-trailing strokes for the entire process.

 

I have read the blogs, and I'm still unclear as to which method is more desirable. Edge-leading produces a more irregular and obtuse edge, but with little burr, while edge-trailing produces a more uniform and keener edge, but with a foil edge. So which is superior?

I also wish he would do a comparison of the edge-leading vs. edge-trailing edges after stropping.

 

Pasted Strop Part 1 shows the difference nicely. I think that the foil edge would be thinner if he used Matrix stones instead. Either way I think this light foil edge will come off nicely with a strop. I just left a message for him to see if he would be interested in trying out the Matrix pass-around kit, I would love to see what difference he could see with these stones with his SEM.

First photos in post 23 show some difference I experienced going from bidirectional to edge trailing only after reaching the apex.

I inherited a single lens microscope from a doctors office, father in law was an MD among other things. It is nothing special but after I got a USB camera that fits in the eyepiece it works very well. Taking photos to look back on is much better than trying to remember what you saw 20 minutes ago. I have been told that a stero microscope is multitudes better but $$$$, I was also told you get what you pay for here and Mitutoyo's are really nice. What I have is good enough to see .0005" microchips in the apex so I am happy enough for now.

Belief changes-
Biggest is edge trailing vs edge leading but some of that has to do with the resin bond stones I developed, the Matrix stones. The diamond is super sharp and will cut with virtually no pressure, something I needed the microscope to understand. Even though it doesn't feel like it they are doing their job with no pressure. Just for the record not all resin bond diamond stones are the same, the Venevs need pressure to cut, they don't cut with light pressure, and leave a much bigger burr. I think this is a hugh deal. It is interesting to see what a leather strop or denim strop - my pant leg, will do to the scratches left on the bevel. It is interesting to see how just a few strokes will smooth the edges of the scratches. Steel at this scale behaves differently than we are used to. Add a little diamond to the strop and wow it can round the apex is just a few passes. Most of the time you want a bare strop.

I used to micro bevel everything but have since done it less. If the workpiece is abrasive or I am sharpening my one ceramic knife I don't micro bevel. I can not put a micro bevel on my Kyocera ceramic knife without microchipping the edge, period, no can do!!!

The apex will lose it's strength over use, don't just refresh the edge too many times. For best results you need to grind it back to expose fresh steel when you sharpen. My main kitchen knife is a Henckels 7" santoku, 16 degrees with a 21 degree microbevel. To maintain the edge I would just refresh it with a few passes at 21 degrees with the 4k stone. I started noticing microchips in the apex, the older the edge the more it would microchip with refreshes. When the steel is fresh I have no issues with microchipping.

Early on when sharpening with the finest Matrix stones, mostly the 4k, I would notice stray scratches in the bevel that I couldn't figure out, this was with edge leading passes. At first I thought it was contamination but it didn't make sense because I would still get them after freshly dressing the stones. When I looked at it under the microscope I noticed the scratches pointed to microchips in the apex. What was happening is the apex would microchip and the chip was causing the scratches. I changed to edge trailing passes and not only did the scratches disapear but so did the microchips. I think the biggest advantage to edge trailing strokes is how the abrasive enters the steel. With an edge trailing pass it gradually enters going from the primary grind to the bevel, a difference of just a few degrees, with edge leading it enters abruptly going from air to a sharp edge. I think this puts much more stress on the apex, which is increadibly delicate. I think the sharpness of diamond exagerates this and that plated diamond tools would be the worst for edge leading passes. This is just an idea I have formulated from a fair amount of observation.

Enough for now, got to get to work.

 

Make sure you're apexing the edge, take a sharpie and mark the edge so you can see where the stone is remving material, make scrubbing passes until a burr is reached on either side. With the matrix stones I recommend using light pressure as too much pressure can create a large burr that can be hard to remove.

As shown in this video @ 8:37 mark only use shorter strokes (around 2-3 inches): I find that short into the strokes will remove even the toughest burrs. I have noticed the full into the edge strokes sometimes seem to flip or create a new burr, I have never had a problem removing a burr with shorter into edge passes.

Good luck!

 

Diemaker, thank you for all your observations and insight. I am a little confused about the about the above statement, especially considering the SOS blog. He seems to dismiss the idea of apex rounding, even when using diamond compound on compressible or free-hanging substrate. The images indicate that there isn't really rounding, but rather that it adds slight convexity to the very apex. What are you thoughts?

 

With 3 micron diamond on a leather strop at the same angle used for the stones on my guided sharpener I can see rounding after 5 passes. After 15-20 passes I noticed I had to change the angle of the knife on my arm to get it to shave, it had to be steeper, and I also noticed the bevel was shrinking indicating the apex was being ground off. This was at an angle of 16 or 21 degrees, it has been close to a year since I tested this out and can't remember. 1 micron diamond isn't so aggressive and .1 micron diamond is useless IMO. I also read the part about a diamond loaded strop not removing the foil burr, hell mine removed the apex so I know the foil burr was getting removed. I strop with no pressure using the smooth side of veg tanned cow hide. IMO you rarely want diamond on your strop, it's just too aggressive.

 

@ToddS found that a 0.25 micron poly-diamond loaded hanging kangaroo leather strop created a substantial 3 micron long foil burr. https://scienceofsharp.wordpress.com/2016/04/14/simple-straight-razor-honing/ That certainly surprised me. I am not contesting that in your circumstance the burr (and more) is being removed; I wish I had an understanding of how both results are possible and what factors are at work.

 

3 microns is just over .0001" so I can't say I did not create a burr that size while removing the apex when stropping with 3 micron diamond. I think that may be just a little too small for me to see with my microscope with a side on view. I would think the biggest factor here is the steel and heat treat.
Some steels form a bigger burr than others, hardness doesn't always matter.