Progression of Stones - Removing Previous Scratch Patterns

[cziv]

I have been using the Magna-Guide (using all of the grist available) & strops for about a year now and getting edges that look like a mirror in low light but in the sunlight they look like they've crusted in cubic zirconium - and, under magnification - as has been mentioned in a couple of threads, I find the scratch marks going all which ways and sub-levels in the sharpened edge, as has also been mentioned.

One of my problems that I'd like addressed is this. When working up a burr and finally spotting it under magnification or by touch, I've spent a long time on one side raising it. To achieve an even scratch pattern on the opposite side is impossible, since a small fraction of the time spent raising the burr is needed to remove it. Anymore passes than that creates another big burr on the opposite side.

Thus, I find myself with a smoother side than the other as I progress. e.g going from the coarse to fine magna-guide, it's impossible to completely remove the coarse scratch pattern without forming a burr the size of a Sunami and so I progress to the finish not having removed all of the previous scratch patterns and am left with a very sharp edge but after generous stopping, one that is still at best, cloudy and at worst all scribbly looking under high lighting or direct sunlight.

Do you have any suggestions for me? I think this uneven scratch pattern issue is at the core of my problem.

 

[Obsessed with Edges]

Lighter pressure, in a nutshell, will make the biggest difference. Heavy pressure is what makes bigger burrs. It also makes the coarse scratches a LOT deeper, and therefore much more difficult to clean up. This is especially true with diamond abrasive. Compared to the steel, diamond cuts like a knife into butter (the diamond is literally hundreds of times harder than steel, in absolute terms). Light pressure is key, when using diamond.

Form the burr with the coarsest hone. After the burr's been 'flipped' to the other side, use the same coarse hone to make a few LIGHT passes on each side of the bevel. This will go a long ways towards cleaning up the uneven scratch pattern, initially. Make the light passes in a linear direction, perpendicular to the edge, as uniformly as you can. When done with very light pressure (just the weight of the blade on the hone, or hone on the blade), this will minimize forming a new burr unnecessarily. Keep inspecting with the magnifier as you go. When the scratch pattern is evened up with the light passes of the coarsest hone, then move to the next hone. Everything from there on out should be done at progressively lighter pressure, as the focus becomes entirely about refining the scratch pattern left by previous steps. Same idea applies; use uniform strokes with each hone, inspecting frequently, to erase the coarser scratches from the previous grit. When that's been done on both sides, step once again to the next hone and repeat the process.

 

[HeavyHanded]

Count the strokes needed to raise a burr on one side. Begin repeating on the other side but stop from time to time and put a few licks on the first side. When you've reached your target number (and added a few extra to keep things roughly even), stop and figure out how many passes you need to flip the burr from side to side and add two or three to this number. Start switching sides at this number and keep it up for a while. By now the burr should be tiny, and the grind should look pretty well swapped over. Sadly, it probably isn't. At the intermediate levels I find it helpful to repeat the entire process at least twice to ensure total grind pattern replacement. Its all too easy to raise a burr, the trick is to raise a continuous (or continuous for all practical purposes) burr. Many people stop when they see the burr, not realizing it has to be continuous from the entire stretch of the edge. You're on the right track when you say it'll be enormous and difficult to deal with if you do it all at once. Takes a bit longer, but if you do a modest grinding and repeat it a few times you'll get better results with a smaller burr. Kind of like spray painting - a handful of light coats vs one or two heavy ones.

 

[cziv]

Am I losing a lot of steel on the edge when I do this or is the scratch pattern just that - scratches? Thanks guys.

 

[Obsessed with Edges]

Am I losing a lot of steel on the edge when I do this or is the scratch pattern just that - scratches? Thanks guys.

Any sharpening, no matter how light, will remove some steel, including the process of refining/removing scratches. The scratches are essentially 'trenches' in the steel, that must be smoothed by removing the steel between the trenches, until everything's at the same level as the BOTTOM of the trenches (hope that makes sense).

Having said that, the focus should be maintained on refining the scratch pattern on the bevel, without significantly altering the shape or integrity of the edge itself. When done properly, at the same consistent angle, this refining process will also make the edge that much sharper (finer). This is why LIGHT pressure is so important, as heavy pressure will do the most damage to the edge. The idea is to very gently 'sneak up' on the edge, without degrading it.

 

[cziv]

Any sharpening, no matter how light, will remove some steel, including the process of refining/removing scratches. The scratches are essentially 'trenches' in the steel, that must be smoothed by removing the steel between the trenches, until everything's at the same level as the BOTTOM of the trenches (hope that makes sense).

Having said that, the focus should be maintained on refining the scratch pattern on the bevel, without significantly altering the shape or integrity of the edge itself. When done properly, at the same consistent angle, this refining process will also make the edge that much sharper (finer). This is why LIGHT pressure is so important, as heavy pressure will do the most damage to the edge. The idea is to very gently 'sneak up' on the edge, without degrading it.

You are by far the easiest poster to understand I've run into. Loved the line about gently sneaking up on the edge! That appealed to my many years of Asian study.

So, I snuck up on it after getting feedback with the coarse stone and worked on getting a nice even scratch pattern. The damage was completely left over by the X-coarse hone I found.

I took a long time with each successive hone giving a little more attention to both sides (in terms of passes) while keeping track of and removing any burrs.

This is my best yet but It's not quite a mirror. But it's darn sure close and I'll get it after I use it and continue to touch it up. Lots of advice, using the hones properly, constant well lit inspection of the scratch pattern and I'm really learning. Beats watching TV!

I need some continuous diamond plates as I'd much prefer to do this freehand. The dia-folds are just to tiny for anything longer than about 3 to 3.5 inches, and then they're kind of a nuisance. I can freehand pretty darn good but darn, a set of those 8 inchers is expensive!

Thanks Obsessed with Edges & HeavyHanded your advice didn't fall on deaf ears. :thumbup:

 

[Chris "Anagarika"]

Thank you for posting this, and the enlightening answers !

I am in the process of learning scratch pattern, edge refinement and also overall blade polish ..

With much gratitude ...

 

[Obsessed with Edges]

...Thanks Obsessed with Edges & HeavyHanded your advice didn't fall on deaf ears. :thumbup:

:thumbup:
You're very welcome.

 

[Lagrangian]

+1 On this thread; very helpful!

You are by far the easiest poster to understand I've run into. Loved the line about gently sneaking up on the edge! That appealed to my many years of Asian study.

So, I snuck up on it after getting feedback with the coarse stone and worked on getting a nice even scratch pattern. The damage was completely left over by the X-coarse hone I found.

I took a long time with each successive hone giving a little more attention to both sides (in terms of passes) while keeping track of and removing any burrs.

This is my best yet but It's not quite a mirror. But it's darn sure close and I'll get it after I use it and continue to touch it up. Lots of advice, using the hones properly, constant well lit inspection of the scratch pattern and I'm really learning. Beats watching TV!

I need some continuous diamond plates as I'd much prefer to do this freehand. The dia-folds are just to tiny for anything longer than about 3 to 3.5 inches, and then they're kind of a nuisance. I can freehand pretty darn good but darn, a set of those 8 inchers is expensive!

Thanks Obsessed with Edges & HeavyHanded your advice didn't fall on deaf ears. :thumbup:

 

[jhakken]

I'd also like to thank those who ask the good questions and those who take the time to answer.

 

[HeavyHanded]

Thanks Obsessed with Edges & HeavyHanded your advice didn't fall on deaf ears. :thumbup:

Very welcome, I'm happy to be of help - this is a deep field of study and I've wrecked a few good knives learning. If I can spare anyone else some trouble that's a good thing.