Fri Aug 17, 2012 10:59 am
So I've been using the Murray Carter free hand technique for some time on my camp knives, larger kitchen knives, with hair popping success, however my shorter blades have proved more of a challenge. Specifically a couple of Wusthof paring knives and most recently an older Protech runt with about a 2 inch blade that has currently engaged me in an epic battle trying to establish good bevels, and so far I'm left with sub par results, bloody finger tips (from stone contact) and occasionally a few choice expletives. However, I have not yet begun to fight. My arsenal consists of an Atoma 140, Chosera 400, King 1K, approx 4K natural stone and a Ozuku natural (all properly flattened); plenty of tools to get the job done, IMO.
Regarding the Protech, I thinned down the secondary edges, which definitely helped, since only the primary had been touched for years. My angles seem consistent, I'm developing a bur along the entire edge and I've attempted establishing the bevels initially on the 140 and I've also tried starting on the 400. I've experimented with all different levels of pressure on the edge. In each case I've developed the burr, removed the burr w/felt block and alternating strokes, but am left with a non-aggressive edge that is unready for my higher grit stones. I'm obviously not establishing the bevel. Any thoughts from my fellow enthusiasts would be appreciated. Thanks and have a great weekend.
Fri Aug 17, 2012 12:59 pm
The burr is a often complex subject and one hard to grasp as its physical properties seem unrealistic. You very well may have established a edge but you left too much debris and plastic flow (excessive burr length) of metal that once ground off by the next stone fractured the apex of the edge in turn dulling the edge.
You could also be that the heavy amounts of metal pushed around by a low grit diamond stone can give a false burr. It will look and feel like a burr that has been formed by two planes intersecting but if removed you will find the apex not completely reached.
You could be using too much pressure which would drive the diamonds too deep into the steel and deformed the apex as it passes. This is what I truly believe it to be. I also think you need to expand the stone set or make it uniform. The mixing of so many abrasive and stone types is a subject we could literally talk for days about.
Fri Aug 17, 2012 1:25 pm
Thanks for the insight Jason. I know too much pressure can be the enemy, and that is probably one of the factors throwing off my game. If I'm interpreting your advice correctly, you're suggesting that an excessively large burr, once broken off/removed, will lead to a dull edge that won't necessarily be improved by progressing to a higher grit stone. I have heard others suggest that the objective is to generate as little burr as possible while still establishing bevels. Back in the day when I was experimenting with the Edge Pro, I remember reading (Maybe via Steve Bottorff of "sharpening made easy"), that it was possible, with practice/feel, to cease honing immediately before the burr actually forms, but just as the bevels meet to form the ideal edge. Always been impressed with the concept, but have yet to obtain that result.
Fri Aug 17, 2012 1:49 pm
I had the same problem. If you look at your edges under a strong light, you may see that your bevels don't actually meet, but may see some light reflecting off of the flat edge where the burr broke off from. Drove me nuts until I looked at the edges and used my loupe, saw I wasn't making the bevels meet up. I got out my Beston 1200 and got the bevels correct with a smaller burr and went from there. Worked great, but drove me nuts for a while until I figured out what was happening!
Fri Aug 17, 2012 2:19 pm
forthosewhotoil76 wrote:Thanks for the insight Jason. I know too much pressure can be the enemy, and that is probably one of the factors throwing off my game. If I'm interpreting your advice correctly, you're suggesting that an excessively large burr, once broken off/removed, will lead to a dull edge that won't necessarily be improved by progressing to a higher grit stone. I have heard others suggest that the objective is to generate as little burr as possible while still establishing bevels. Back in the day when I was experimenting with the Edge Pro, I remember reading (Maybe via Steve Bottorff of "sharpening made easy"), that it was possible, with practice/feel, to cease honing immediately before the burr actually forms, but just as the bevels meet to form the ideal edge. Always been impressed with the concept, but have yet to obtain that result.
I think you understand the first part completely.
The concept sounds great but is impossible in reality no matter how hard you try. You would need perfect form and use of pressure along with a abrasive stone paired with a steel that forms as little plastic flow as possible, such pairing is why sharpeners like myself will eventually have enough stones to build a house. It could also only be one stone as progressing to a finer grit repeats the process just on a smaller scale and the concept becomes a over simplification of what is actually happening.
Reducing the pressure lessens the depth of the cut and "polishes away the burr", this is something that can be done on every stone from start to finish. Once you are able to do this consistently your ideals of "sharp" will be completely changed.
Fri Aug 17, 2012 3:02 pm
Outstanding, that's what makes this experience enjoyable is having other like minded people at various stages of their own sharpening journey from which to glean knowledge. Thanks again Jason and Taz.
Sun Aug 19, 2012 2:35 pm
Well, you may also be expecting too much from this particular knife. Going past a 4k or so edge may just be a waste of time.
I do like the idea of not making big burrs. Remember that if you do make a burr and break it off, the two sides of the knife are no longer meeting - you just have the jagged broken surface where the burr was broken off.
So this leads to the other point Jason makes that I would emphasize. Heavier pressure generates bigger burrs. I would add that light pressure on a burr results in abrading the burr off rather than breaking it off - a more elegant approach.
Right before burr formation you can notice a marked increase in sharpness. This takes time and practice to 'get'. It is worth learning. Even if you don't get this it will force you to spot burr formation at it's beginning, not when it is a great big burr.
Taz's point of using magnification to actually SEE what you have is essential. Especially for abrasion resistant steels, you can get close to an edge but still be quite a way from actually getting the two sides to meet.
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