I suspect your purple welsh slate is a purple Llyn Melynllyn ?!Something I find my Welsh slate I have to be a bit careful of it can give me some tooth but it can also go so damn smooth that you can't cut tomato or even newspaper.
That's exactly the stone and yep you're on the money the knife wont go through a tomato if I go real well on it but if I cut though carrots and that then it'll go through the tomato definitely a balance and yep I've got the nagura with it.. Never thought to make the slurry I was always told it would give a worse edgeI suspect your purple welsh slate is a purple Llyn Melynllyn ?!
In that case I know your problem, I own this stone myself. Do you have a nagura for this stone? Alternatively, you can create a bit of slurry / mud on the stone with a diamond plate.
If it's a purple llyn melynllyn then only use the stone with slurry / mud. Without it, the stone polishes too much and creates a sharpness without bite
Maybe 'rounded' isn't the best term for me to use. But not being able to slice paper at any grit sounds like the apex isn't fully formed. Or leftover burr.You know, as a side remark, something about rounded edges kind of confuses me. How is it possible to really produce a rounded edge with a stone? As long as you never raise your angle more than 20 degrees on each side, and you hit every part of the edge at some point, you are guaranteed to have an at most 40 degree apex at every point along the edge. I mean, maybe slurry or severely nonflat stones can cause problems and make the edge more rounded, or metal can build up at the edge in the form of a burr and you can not remove it correctly. I just see people (not @M1k3) blaming a wobbly hand for a rounded edge, and I don’t see how that’s related. In some sense, the above is why freehand sharpening works at all, and why we don’t all need to use jigs. I mean, wobbling is bad for other reasons, since you want the geometry behind the edge to be consistent, and you don’t want to be hitting the edge more in one part of the blade than another, f’ing up the profile, and it probably makes sharpening more efficient if you don’t wobble, but I don’t think it causes rounded edges. Or maybe there’s some other relationship I’m missing.
Maybe 'rounded' isn't the best term for me to use. But not being able to slice paper at any grit sounds like the apex isn't fully formed. Or leftover burr.
If you are spending 30-45 minutes to sharpen a knife that is already sharp enough to cut newspaper you should definitely buy a 500-1000 grit stone. Honestly you are just wasting your time if you don't.This to me is dulled and its what I would normally spend half an hour to 45 minutes bringing back up to scratch.
For "rounded edges" from a "wobbly hand", I get it the idea. Basically meaning that if you don't hold a pretty consistent angle you can round over the edge. It would different all along the edge and on both sides though so not sure "rounded" is the best descriptor but I get it.
Thing is, you're not really rounding the actual apex by doing that, you're convexing behind the edge. As long as your angle never exceeds 20 degrees, say, you'll always have an acute apex (given that you do hit it at some point when you sharpen), it's just that the bevel behind it will be flat if your angle is constant vs convexed if you wobble. Anyway, that's at least the point I was making.
Ah. Got it this time. I wasn't considering the max angle.
Bear with me here... If the apex is at say 15 degrees and you wobble around from 15-20 there will be "rounded" spots though yeah? Wouldn't you be "rolling" the apex once you exceed that 15? Honestly not trying to argue semantics. I think it is interesting.
Bear with me here... If the apex is at say 15 degrees and you wobble around from 15-20 there will be "rounded" spots though yeah? Wouldn't you be "rolling" the apex once you exceed that 15? Honestly not trying to argue semantics. I think it is interesting.
Thing is, you're not really rounding the actual apex by doing that, you're convexing behind the edge. As long as your angle never exceeds 20 degrees, say, you'll always have an acute apex (given that you do hit it at some point when you sharpen), it's just that the bevel behind it will be flat if your angle is constant vs convexed if you wobble. Anyway, that's at least the point I was making.
You know, as a side remark, something about rounded edges kind of confuses me. How is it possible to really produce a rounded edge with a stone? As long as you never raise your angle more than 20 degrees on each side, and you hit every part of the edge at some point, you are guaranteed to have an at most 40 degree apex at every point along the edge. I mean, maybe slurry or severely nonflat stones can cause problems and make the edge more rounded, or metal can build up at the edge in the form of a burr and you can not remove it correctly. I just see people (not @M1k3) blaming a wobbly hand for a rounded edge, and I don’t see how that’s related. In some sense, the above is why freehand sharpening works at all, and why we don’t all need to use jigs. I mean, wobbling is bad for other reasons, since you want the geometry behind the edge to be consistent, and you don’t want to be hitting the edge more in one part of the blade than another, f’ing up the profile, and it probably makes sharpening more efficient if you don’t wobble, but I don’t think it causes rounded edges. Or maybe there’s some other relationship I’m missing.
I think that you are right. I haven't rounded an edge on a stone in many years by basically following this logic. And I get pretty aggressive with the high angle passes on fine grit synthetic stones.
I have noticed what I would call "rounded edges" on softer stainless when I over do convexing on the 1X30 slack wheel. But that is a completely different ballgame when that thing is moving 1600 feet per second (edit: 1600 feet per minute). The apex just melts.
As long as you never raise your angle more than 20 degrees on each side
If the apex is at say 15 degrees and you wobble around from 15-20 there will be "rounded" spots though yeah?
Hehe... why place a limit in either direction? Model the sharpening angle as a stochastic variable under some distribution. Lets choose a Gaussian because they are 'friendly' and say the mean is 20 degrees with a standard deviation of 1.25 degrees. That means approximately 68% of the work is done within +/- one standard deviation (1.25 degrees) of the mean. And approximately 95% of the work is done within +/- two standard deviations of the mean (from 17.5 and 22.5 degrees). Some of that will be 'rounding' (high angles) and some of that will be 'thinning' (low angles).
The better you get at honing, the smaller your standard deviation! I suppose that means you will be doing less 'rounding' and 'thinning'.... and more... 'sharpening'...?
Even if it's over the topic, the Dai's look very good!Another conversation about slate eh? Count me in!
Though I'm sure I've done it to a million knives I don't really know what a rolled edge is or feels like, but... I have certainly used slates that give the kind of edge described; they can excel at certain 'sharpness tests', and be pants at others.
The reason for this, I think, is because of its form, and formation (pic attached). When you sharpen on slate you are sharpening on quartz that has been flattened parallel to the layers of the slate during the metamorphic process. And flat quartz doesn't do a huge amount of cutting. You'd have thought you could get around this by cutting the face of a stone across layers, but often ime you can't do this. A lot of slate really is quite layered, and it'd chip and break up if you tried, it would also absorb a huge amount of water and feck up the stone.
The slates I've found that have the most cutting ability are ones in which you have the layers formed across the former bedding planes of the original mud. You're still sharpening on a single layer of slate, but across layers of the original deposits. A second pic attached, showing the wavy lines on the completely flat and dry surface of one of my stones, on the left. It has been flattened along a layer of slate, that was formed across the bedding planes.
But yeah - slates finish more refined than other stones of comparable grit ime. And I imagine the when you get to the mega-fine levels of some Welsh slates this is going to be really quite polished. Though as KS said - mud helps - release some of those bits of quartz and you're no longer sharpening just on flat stuff.
[This is all conjecture and extrapolation from what I've read and experienced. So may be wrong, and/or it may not apply to all slates.]
Absolutely true!!!!Coarse stones can be misunderstood. True... their primary use is thinning, removing chips and reseting bevels. Why? Because they remove steel quickly. But that doesnt mean you only have to use them for those tasks. Coarse stones are actually far more versatile than high grit stones. You can get coarse grit stones to mimic high grit stones to some degree but not vice versa. It is about pressure control. In the right hands a coarse stone can produce an edge that is sharper than necessary for use in the kitchen.
Even if it's over the topic, the Dai's look very good!
Enter your email address to join: