Rambling about pressure

So I typically use more pressure than I should on both the hone and strop. I get good shaves but I don't have edges as sharp as most guys. I like the simplicity of using a little pressure on the hone (it gets sharp fast) and the strop (it gets stropped in a few strokes as well).

I sometimes flirt with the idea of honing with a light touch, and sometimes it works and sometimes it doesn't. I chalk it all up to needing practice.

Recently, I talked with Robert Williams (via PM) about pressure and he gave me some interesting insights. I've talked with a few other experts on other sites as well.

We all know the importance of using light pressure when honing, but I wanted to discuss something a little different that others may not truely appreciate, utilize, or agree with.

Its the idea of pressure variance.

One thing I have noticed is the importance of using the "right" amount of pressure when honing . . . I have also noticed the "right" amount of pressure when stropping.

I have noticed that a razor requires less and less pressure as it gets honed. The sharper, the less pressure. Most of us know this, but many only talk about pressure being "light" and therefore many newbies will miss important ideas about how to hone (I think).

Now, I've noticed many times in the past, but never really got it clarifed in my head that the strop is the same way.

I have noticed that pressure (light, yet firm, maybe a pound or two) is helpful on the strop, but that as the blade gets more and more smooth, the pressure needs become lighter and lighter. Eventually, the pressure needs to be really light.

I wonder if guys that use pastes (.5 and .25) a lot instead of stones only use light pressure when stropping, just like guys with sharp razors only {need to} use light pressure when honing . . . ???

So, to make an already too long post, to the point (finally). I think that less and less pressure should be applied to a razor while honing to get it really, really, sharp and that less and less pressure should be applied on the strop to get the razor really, really, smooth.

Any thoughts?

I agree with the pressure variance on the hone. It's the same principle you'd use when restoring a blade's finish -- you start with a heavier sand paper, gradually using grits that are more and more delicate; focusing on areas (of the razors edge, when honing) that need special attention.

I don't have any experience with strop pastes, but going from firm to light strokes on the leather makes just as much sense as on the stone.

When I'm stropping I actually lift the razor's spine off the strop a tiny bit. It doesn't dull the edge at all. Say you were trying to strop a pencil, laying it flat on the leather, moving it eraser end first --- you wouldn't come into contact with the bevel all that much, would you? Same idea. It works well for me.

Not to hijack a thread (more to offer a parallel approach), but my approach has been to maintain light and constant pressure throughout the honing process (stropping too for that matter). Where some use a heavier hand early in the process when they need to remove more metal or shape a rather dull blade, I simply go to a lower grit hone---same pressure. Rather than heavy(er) pressure on a 4K, I move to a 1K until the edge is adequate for 'normal' 4K honing. Rather than really working on an edge with heavy pressure on a 1K (circles or whatnot) to build an edge or remove a deep nick, I do the unthinkable (to some). I actually go to the 220 grit side of the hone--again, at a light but constant pressure.

Anyway, it works for me...
Just another data point,
Ed

Single grit and vary the pressure or single pressure and vary the grit. Both sound about right to me also.

This is a good thread! Thanks Alan and Ed!:)

When I hone or strop a razor the only pressure I put on razor is actual weight of razor....Honing is about finess letting the weight of blade do the work to create the fine edge...It seems any time I used pressure on hone I ended up with a sub sharp edge compared to letting razor do it...also the reason razor felt lighter in pressure as razor became sharper may have been that as you swithed to finer grade hone...thehone surface was smoother thus less drag on blade...when I strop, I strop very rythmicly and quickly ...I dont think I have the control to very my pressure on the strop...I have learned thru experience what the drag feels like leather on blade when I am stroping effectively...I can tell by feel whether my razor will be sharpafter stroping...

I only use enough pressure to ensure the blade is kept flat, nothing more. With too light a touch I cannot feel it is flat so it's just enough to feel that both edges are touching.

Gary

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Originally Posted by AFDavis11

So, to make an already too long post, to the point (finally). I think that less and less pressure should be applied to a razor while honing to get it really, really, sharp and that less and less pressure should be applied on the strop to get the razor really, really, smooth.

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Pressure may not matter as much with barber hones, which tend to be finer and can be used dry, wet and with lather to vary their cutting action. I could see how on an aggressive hone like the Norton 4/8K it needs to be watched carefully.

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Originally Posted by Blade Wielder

I don't have any experience with strop pastes, but going from firm to light strokes on the leather makes just as much sense as on the stone.

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I don't know about that. Leather stropping does no sharpening nor any real polishing. It's just not abrasive enough. The principle behing it is that shaving deforms the microserrations, making them spread out so the blade seems thicker. Much of it is elastic, and the blade slowly returns to its aligned state, even without stropping, but a certain amount of misalignment remains, and that taken care of by stropping.

I don't know that variation in pressure really matters much. it seems that using the right pressure will realign the microserrations. Anything significantly more or less will simply overdo it (possible causing microserrations to break off from stress) or be too slow.

There's a sharpening study done by a professor which is posted here. He found that stropping after honing made very little, if any, difference. That's consistent with theory, since a newly honed edge would not have much misalignment in the microserrations. In fact, it seems that stropping before honing would minimize wear and make it easier to get the sharpest edge.

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Originally Posted by ForestryProf

Rather than heavy(er) pressure on a 4K, I move to a 1K until the edge is adequate for 'normal' 4K honing. Rather than really working on an edge with heavy pressure on a 1K (circles or whatnot) to build an edge or remove a deep nick, I do the unthinkable (to some). I actually go to the 220 grit side of the hone--again, at a light but constant pressure.

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High pressure is never good. It causes the edge to lift up so your're actually honing or stropping some location back from the edge. What good does that do?

But as long as you don't go too far, pressure variation is good because it gives you more of a continuum of cutting action. There's big jump from a 1K to a 4K at the same pressure.

I like a coarser stone when needed, but I find anything coarser thana 1K is just too fast. It cuts too fast and leaves a roughness in the edge that just makes more work later on.

I guess I should clairify. The only time I go to the 220 is on razors that most of us would consider trashed (or in need of being sent out for regrinding). If I've got a full bevel deep nick in the blade, I have no problem using the 220, because any micronicks or deep scratches that this stone would cause along the rest of the edge are still much shallower than the flaw that I'm attempting to remove. When the damage I'm attempting to remove approaches the depth of the scratches/nicks left by the 220, I switch to the 1K. Thus, no additional time honing due to damage done by the coarse stone; I've only rescued a razor that would otherwise be trash.
Ed

Howdy,

I wonder if placing the stone on a postal or similar electronic scale and zeroing it out, would give some sort of way of measuring the pressure of the stroke?

Me? I just go into random flail mode and trust in the Force to get my razor sharp...

regards &C
LG Roy

Even after my 12K and CO on balsa when my blade is what I think to be sharpest I still see a big difference after my final passes on my linen and leather. No question about it.

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Originally Posted by Joe Lerch

I don't know about that. Leather stropping does no sharpening nor any real polishing. It's just not abrasive enough. The principle behing it is that shaving deforms the microserrations, making them spread out so the blade seems thicker. Much of it is elastic, and the blade slowly returns to its aligned state, even without stropping, but a certain amount of misalignment remains, and that taken care of by stropping.

I don't know that variation in pressure really matters much. it seems that using the right pressure will realign the microserrations. Anything significantly more or less will simply overdo it (possible causing microserrations to break off from stress) or be too slow.

There's a sharpening study done by a professor which is posted here. He found that stropping after honing made very little, if any, difference. That's consistent with theory, since a newly honed edge would not have much misalignment in the microserrations. In fact, it seems that stropping before honing would minimize wear and make it easier to get the sharpest edge.

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Agree, for two reasons. Verhoven was measuring sharpness by measuring the actual edge thickness with an SEM. He wasn't shaving his face, so his research can't really say that stropping isn't needed for shavers. Other factors might be at work such as edge shape and uniformity. Also, he was only stropping freshly honed edges, so that says nothing about daily stropping before each shave.

In theory, if bending deflection is a factor then pressure on the coarse hone and light touch with the finishing hone could give a subtle micro bevel effect that could be beneficial.

Gah. I hate zombie threads, but this is a good one.

I think it's really a question of efficiency, same as using a progression of stones when honing. You can get a razor sharp using nothing but a finishing hone, or you can use a 1k,2k,4k etc. Both methods are capable of achieving the same level of sharpness - assuming your finishing hone is the same in both methods and your patience doesn't run out. Similarly, you can get a razor sharp using decreasing pressure on the strop or hone, or use more laps with nothing but light pressure. Both seem to achieve the same result, you just have to be prepared to use more laps.

I'm not consistent in this. When honing I use decreasing pressure, but when stropping I generally just use a light touch and lots of laps (20-50 linen, 40-70 leather). But my stropping lap speed is so much faster than my honing lap speed, so that may be why I use the theoretically less efficient stropping technique.