veritas LAJ A2 or O1 blades?

[Jacob]

..... ....The rasp scratches from the 2 planes that make up the bevel do not truly meet, but there is a sort of 'doughing over' ...

not if you don't "dough it over" - why would there be?

a...... Now swap to a plane, the edge is super sharp, but under a lens, the rounded apex will be apparent.....

Not if you look at the many photos available on the net. On a sharpened edge you will be looking at a roughly torn arris (given enough magnification). The "teeth" of an abrasive will rip into and rip off material, without stopping to "dough over".

Not looking at things seems to be a major issue nowadays - there is a thing called reality you know, which is usually more interesting, surprising and more complex than we imagine!

Even the "perfect" surface of a crystal is as rough as a badgers a****s.

 

[woodbrains]

Hello,

I've just discovered a new law of physics. 'If Jacob can't understand it, it cannot exist' .

Sine Jacob cannot understand most of the posts here, the posters do not exist and Jacob is talking to himself.

At a different magnification the transitional point will reveal itself. You can only see what the magnification in the photos will allow. It is not possible to have zero transition, there will be a dimension to it. The finer the sharpening scratches the smaller this will be, but always present. The fact that abrasives have size mean this must be the case.

Do the rasp experiment Jacob and you will see there will be a transitional point that you can never lose, you do not have to purposely dough it over, the nature of abrading dictates it will happen.

Mike.

 

[Corneel]

The problem with looking at these microscopic images is that you only see a 2 dimensional picture. You can't see the front edge. In this paper from prof. Kato you see more of a 3D image in figure 1 http://planetuning.infillplane.com/html/review_of_cap_iron_study.html. Hard to see the front of this edge. The jagged edge is obvious. And it is reasonable to assume the edge isn't absolutely sharp, because atoms have size too.

But when looking at this figure I wonder what is more relevant, the slight radius or the jaggedness?

 

[bugbear]

But when looking at this figure I wonder what is more relevant, the slight radius or the jaggedness?

Interesting point, since both are present.

Edit; more importantly, as you sort-of-indirectly-stated, they're just two views of one thing.

If you view a cross section from the back to the edge, you'll see a radius. Even it's the edge is not actually nice and round, there will obviously be a circle bigger than is needed to contain the cross section, and (conversely) a circle than is smaller than is needed. As you shrink one circle and enlarge the other, they'll meet at something that can reasonably be called the radius of the edge.

If you view an edge in simple plan, you'll see the raggedness.

BugBear

 

[Jacob]

Hello,

I've just discovered a new law of physics. 'If Jacob can't understand it, it cannot exist' .

Sine Jacob cannot understand most of the posts here, the posters do not exist and Jacob is talking to himself.

At a different magnification the transitional point will reveal itself. You can only see what the magnification in the photos will allow. It is not possible to have zero transition, there will be a dimension to it. The finer the sharpening scratches the smaller this will be, but always present. The fact that abrasives have size mean this must be the case.

Do the rasp experiment Jacob and you will see there will be a transitional point that you can never lose, you do not have to purposely dough it over, the nature of abrading dictates it will happen.

Mike.

There will be scatterings of molecules along what is effectively a torn edge, which hardly have a radius in your sense. The rounded-over appearance of a blunt edge (your "radius") soon disappears with sharpening and you have a jagged torn appearance under magnification.
Have a look for yourself - don't just idly speculate!

....I wonder what is more relevant, the slight radius or the jaggedness?....

For a carving, slicing, action the jaggedness is important, which is why carving knives are often sharpened off the edge - to build up a crude saw like edge, but for the straight push of a chisel a more cohesive edge is require so you sharpen on to the edge (towards the handle).
So a razor is more like a saw and a chisel like a wedge.

I suppose there ae two distinct stages in sharpening - first you take off the "radius" - the blunt edge visible as it reflects light, then the refining of the non radiussed edge with decreasing grit sizes. Not a steady progression through radii.

 

[bobbybirds]

I have A2 blades for all my LV planes (LAJ, BUJ and BUS) and never have an issue with chipping, and because the blades are interchangeable between these three planes, I just keep them all sharpened different (25, 38 and 50 degrees) and switch them between planes as needed. I did however, purchase one PMV11 blade to try when they were introduced and I do find it more durable and requires less sharpening but whether or not the extra cost is justified is something for you to determine. I keep it sharpened at 50 degrees for planing gnarly grain specifically and use the A2 blades on everything else...

 

[woodbrains]

Hello,

There is not really any point debating what exactly the edge looks like, as it is getting off the point. The fact is that there is thickness at the edge and the aim is to make this as small as practicable using fine grit abrasive. The thing I am trying to get across is, that this 'transition thickness' ( if radius is upsetting someone ) becomes greater, as the bevel angle increases. Redictio ad absurdum; two sharpening planes at 0 deg separation will have no transition between them, as the angle increases the transition becomes more significant. So high bevel angles will suffer the most. SinceA2 steel is already a greater sufferer of this. I was contending that O1 could still be a better bet, even though A2 benefits from slightly higher bevel angles to reduce the tendancy it has to crumble.

Removing the wire edge is a prime cause of this 'transition thickness' and O1 loses the wire edge cleaner than A2 which is an advantage for a start. The steels grain structure, no doubt has much to do with it.


Mike.

 

[Jacob]

Hello,

There is not really any point debating what exactly the edge looks like,.....

Why not? It's interesting to know whats going on there

as it is getting off the point.

It is the point!

The fact is that there is thickness at the edge and the aim is to make this as small as practicable using fine grit abrasive. ......

Not thickness or "radius" really. The radius is removed when the burr is generated.
Abrasive scratches form a crude sawtooth edge and finer abrasives make smaller scratches and a finer sharper edge. The finer the edge the faster it will be lost in use so there's a happy mean somewhere.

 

[woodbrains]

Not thickness or "radius" really. The radius is removed when the burr is generated.
Abrasive scratches form a crude sawtooth edge and finer abrasives make smaller scratches and a finer sharper edge. The finer the edge the faster it will be lost in use so there's a happy mean somewhere.

Hello.

Ron Hock thinks there is a radius. He makes edge tools in O1 and A2 which he also cryogenically treats to keep the grain structure small. He knows what he is talking about.

The burr is hanging on to the edge, till it is removed. It is not hanging on at zero thickness, is it? When it breaks there will be a transition between both mating edges. The grain structure in the steel makes a lot of difference. These are larger than molecules and have significant size. The grains in A2 can be larger than Carbon steel.

Try the rasp experiment, you will see macroscopically what is happening. Your microscopy pictures are limited in that they will only show what the experiment wanted to show.

Mike.

 

[Jacob]

Not thickness or "radius" really. The radius is removed when the burr is generated.
Abrasive scratches form a crude sawtooth edge and finer abrasives make smaller scratches and a finer sharper edge. The finer the edge the faster it will be lost in use so there's a happy mean somewhere.

Hello.

Ron Hock thinks there is a radius. ......

Well he's wrong then - if he means that ever diminishing radius which you referred to. More like saw teeth (before they are rounded back with use). Does a sharp saw edge have "radius" in any way? If not why not?

You can see the rounded over edge of a blunt tool as a line of reflected light. You can't see it after a few seconds on a coarse stone. Where has it gone? Has it become invisible? How can this be?

 

[woodbrains]

Disagreeing with metallurgists over the grain structure of steel. Evidently, your hobby is making an ass of yourself.

Mike

 

[iNewbie]

This is what Hock said:

Hock's Sharpening notes

 

[Peter Sefton]

I think Ron covers it all really; all you need to do is practice and find your own way. If that doesn’t work go on a course so someone can show you where you may be going wrong.

Peter

 

[G S Haydon]

Just clarify,

The debate is at a microscopic level does the edge appear jagged or rounded or both? Please keep to one sentence answers :wink:

 

[Jacob]

Had a look. He says "there will always be some radius to an edge". I think this virtually meaningless but I now see which guru you are all mindlessly following and quoting word for word!

....The debate is at a microscopic level the does the edge appear jagged or rounded or both? Please keep to one sentence answers :wink:

Good question. The answer is of course "jagged" but the true believers will say "radiussed" or something like that, which isn't quite the same as "rounded", for some reason of their own making. :lol: :lol:

OK so that's the one sentence. Here are a few more (sorry!).
R Hock burbles on quite harmlessly but the true believers hang on every word, but selectively.
Frinstance R hock says It’s the blade’s edge radius that reflects light and if there is no radius — The Goal — there will be no reflection.) which is exactly what I said only a post or two above! And I've never read anything before by R Hock and hope to keep it that way - it obviously does peoples heads in! They do keep trotting out these bits of gospel and chanting mantra. :roll:
PS I 've got "Hock" blade but it was made in France so it's just a brand thing I suppose. Nothing wrong with it I hasten to say.
I guess I could get them to make some the same for me and call them the "Grimsdale Thunderbolt" or something. :lol: :lol:

 

[David C]

This mockery of serious individuals, who know a great deal more about their subject, than Jacob does, seems both spiteful and demeaning.

Shame.

David

 

[G S Haydon]

Maybe one day these posts will be of a calmer nature and rationally explore ideas and concepts :lol:

I must admit, with my simple mind, I have lost track of what the point of the conversation was.

 

[Phil Pascoe]

After that second sentence I fancy your head is slightly above the parapet.

 

[woodbrains]

Hello,

I have met Ron Hock and been to his workshop. He is a very nice and knowledgeable man. His blades are produced to his specs in th USA and France, as they have the scale to mass produce that his little one an shop is not capable. He did produce them there himself until the scale of operations needed to be bigger. I actually find his A2 cryo irons rather better than Veritas and LN.

He still produces special items, knives and things for the more specialised client. And taught me a little about hardening and tempering.

The original query I have is, A2 ( not Hock A2 I should add) tends to crumble at low honing angles so in a LA plane keeping them with a larger honing angle would make sense as this increases the EP of the plane for difficult grain and avoids the crumblig problem. However, since A2 tends not to sharpen to the smallest sharpening radius we are aiming for, the high honing angle will exacerbate the effect. So is O1 steel a better bet, since the sharpening radius can be smaller. If you like, the grains are smaller, so the minimum size this radius.can be is necessarily smaller. This has a lot to do with how fine and easily the wire edge will break away.

The man who didn't even have the wit to test the differences between the A2 and O1 blades when he had them, has nothing worthwhile to comment on the subject, by default.

Mike.

.

 

[G S Haydon]

After that second sentence I fancy your head is slightly above the parapet.

Only because I'm simple. I just start to struggle when it comes down to an argument based on the magnified image of an edge and what can be seen and what it should be referred to as. I will freely admit I'm no expert on this and it takes me a moment or two to try and get my head around it. Being a joiner from the industrial age means this topic was not part of the apprenticeship. I will freely admit to only now forming a firm view on the whole clogging plane/adjustable frog position argument. Do I risk sharing that view here, probably not...........