Plane iron clearance angle.

[monoman]

Bugbear, could you rephrase. I'm not sure exactly what you are trying to say.

 

[bugbear]

Bugbear, could you rephrase. I'm not sure exactly what you are trying to say.

you said:

<i>Some here seem to think that the blade starts sharp and after a while looks like the Brent of Steve's drawings when it is dull. That simply is not the case. The blade looks like that from the very first pass - only the scale changes.</i>

I think "some here" are quite right. Your point about scale is accurate (in that a sharp edge under enough magnification is round) but not relevant. An edge that requires extreme magnification to appear round is what we normally, and reasonably, call "sharp".

BugBear

 

[Jake]

In other words, perhaps, about when you can count the angels dancing on the edge, it is time to stop (or do I mean strop?).

 

[woodbloke]

In other words, perhaps, about when you can count the angels dancing on the edge, it is time to stop (or do I mean strop?).

Succinct, as ever...nice :lol: :lol: - Rob

 

[monoman]

<i>Some here seem to think that the blade starts sharp and after a while looks like the Brent of Steve's drawings when it is dull. That simply is not the case. The blade looks like that from the very first pass - only the scale changes.</i>

I think "some here" are quite right. Your point about scale is accurate (in that a sharp edge under enough magnification is round) but not relevant. An edge that requires extreme magnification to appear round is what we normally, and reasonably, call "sharp".

Im not arguing about that. Yes. Look at a really sharp edge under an scanning electron microscope (SEM) and it will look anything but sharp, maybe even round. So what? I've never looked at any of my blades under an SEM, have you? None of this is particularly relevant to us planing wood.

For out purposes, let's say the black line represents a freshly sharpened blade, and the red line is a worn blade. What I meant by scale is that the blade will start to look like the red line straight away, only the size of it will be smaller. It changes gradually as each metre is planed.

My interest is what happens as a blade dulls, and if sharpening times can be extended by different sharpening techniques or levels of finish. For years the highest grit I used was a 6000 stone. Now I'm finishing off with 10 seconds on the 10,000 stone and a 10 second strop and not having to sharpen anywhere near as often. The blade does not feel any sharper or cut any cleaner. I just lasts longer.

I don't strop in between sharpening because if I have to remove the blade to strop it, I might as well give both faces a quick swipe on the 10,000 first. I doubt it would take any longer. Actually, this is what I do with my chisels all the time. The A2 steel Lie-Nielsen in their chisels uses seems to last 2 or 3 times longer using this practice.

 

[bugbear]

For out purposes, let's say the black line represents a freshly sharpened blade, and the red line is a worn blade. What I meant by scale is that the blade will start to look like the red line straight away, only the size of it will be smaller. It changes gradually as each metre is planed.

No, not understanding that all. Sorry. I *thought* you were saying that all edges are round, on some scale.

If that's NOT what you're saying (which you emphasised quite strongly enough, thank you) I don't know what you ARE saying.

BugBear