Thread: Why hone with light pressure?

Originally Posted by AFDavis11

There are probably a few reasons, one being spine wear, which I have seen when using too much pressure, but the predominate, documented, reason is because of upward edge flex as the blade gets sharper.

I can also tell you, pretty emphatically, that it works. And I add that because there are a lot of things I don't know about straight shaving (like exactly why something works). I just know through trial and error (years of it) that light pressure does in fact work.

Light pressure is one of the main things that seems to help get a blade sharp and has the least documented support for doing it. I find that interesting as well. It is documented, but not as much as I would expect it to be .

I have always suspected that the tinsel strength of steel would make it fracture when being honed instead of flexing which would make it duller. I think overhoning is a form of fracturing of the metal. I'm not sure how anyone, historically, could really know that the edge was tipping upward when being honed.

I will tell you that whenever I'm trying to really impress someone with the quality of an edge I have honed I often think of it as sculpting the edge as lightly as possible to produce the thinnest possible edge without fracturing it.

If you really want to take honing to a wicked science spend a few years trying to learn how to hone an edge using about half the weight of the blade. That is, to actually relieve the weight of the blade off the hone, while stroking. The results are pretty darn neat.

A huge +1 on this post. In my honing experience, sharpness is directly related to pressure. The lower the pressure the sharper the razor will be. I think the forces that impact the very edge can be enormous in relation with how thin and fragile the steel is at that part of the blade. Keeping a hone well lubricated and pressure as low as possible (while maintaining an even stroke) seems to allow for the best results. On my DMT1200 I have witnessed this countless times. I always aim for a positive HHT, before I finish honing on the DMT. It really make all the difference to minimize the pressure as soon as the edge starts passing the TNT. Soon thereafter it 'll pass the HHT.

For me, speed helps. I usually start on a hone with doing slow and precise X-strokes, watching the wave run up the edge. After a while, I feel that my "muscle memory" has locked on to the motions and then I start to speed it up a little, adding a sort of a soaring idea to the the blade. I realize that it's not the common way to do it, but it really makes a difference in my end results. I also pay a lot of attention to turning over the razor as smooth as possible. I start lifting the edge near the end of the stroke and I'm already commencing a new stroke before the edge touches down again.

I'm not saying this is the only way to get a keen edge. I merely want to illustrate how much pressure management relates to good honing results.

Best regards,
Bart.

I think that the when the edge is honed to the optimum level of sharpness that that hone can give, the blade edge vacuum sucks down onto the hone of its own accord. This suction is the optimum pressure.

When you really know your hones, you can feel the suction and at that point you should stop as the hone is adding no further value to the edge. In fact it may well be reducing the fin that you have worked so hard to create.

How do I know this? Well I have no scientific answer. Its a bit like knowing when the sugar has dissolved when you stir your coffee cup with a spoon. You just feel it.

It is the best way to finish but to do it throughout the process I cannot understand. why? because my razors are very sharp and I don't need to spend hours and hours getting there.

Thanks everyone. Everyone has some really good input. I've gotten some good ideas that I want to try.

I don't use the same light pressure throughout the process. My pressure gets lighter and lighter as I finish up on each grit. On the very highest grits/paste I use the lightest pressure throughout.

I think this post on pressure pretty much says it all, it really helped me to speed up and improve my honing. Anybody know if it's in the wiki yet?

Originally Posted by Sticky

I don't use the same light pressure throughout the process. My pressure gets lighter and lighter as I finish up on each grit. On the very highest grits/paste I use the lightest pressure throughout.

Does this mean that at the beginning of each grit you start off "heavy", and then go light? Or are you saying that it's just a steady easing of pressure?

Originally Posted by biggbadwulff

Does this mean that at the beginning of each grit you start off "heavy", and then go light? Or are you saying that it's just a steady easing of pressure?

In this post here Glenn says exactly what The Topher told me when he was showing me how to hone at his house. "Just enough pressure to keep the blade flat on the hone." What Chris showed me was actually more pressure then that in setting the bevel but once the bevel was set then it was the light "just enough" pressure from there on out.

Originally Posted by biggbadwulff

Does this mean that at the beginning of each grit you start off "heavy", and then go light? Or are you saying that it's just a steady easing of pressure?

Sorta'.

Using a 1200 DMT D6E to set bevels; "heavy" is about 3 to 5 times the razor's weight, beginning with circular motions (mostly). Once my bevels start to meet, I use lighter and lighter pressure with the standard x-strokes until I pass the TNT and marker tests. I am assuming an average razor weight of about 45 grams.

By the time I am on 8k; heavy might mean twice the weight of the razor, while light means just as light as i can get it. My "light" pressure is the same on every hone. My "heavy" beginning pressure, on each hone, gets lighter as I proceed upwards on each finer grit. By the time I get to 12k and above, the difference between my "light" and "heavy" is slight. If I go to 0.5 chrome oxide or newspaper, there is virtually no difference at all.

Recently I used an Ohaus scale to measure my honing pressure on barber hones. I was surprised at how high my lightest pressure actually was. Using the scale improved my lighter pressure ability quite a bit (a useful experiment).

I use the D8E 1200 too with some pressure. If I get chipping with the diamond plate I switch over to a Shapton 1K followed by the 2K. The Topher showed me how to set bevels and I have seen him in removing a good sized chip use enough pressure using circular strokes to wear through the tape on the spine and have to replace it. I have never used that much myself. I prefer to take more time if need be.

Once I get the bevel set I don't use much pressure. As noted above, Topher and Glenn have both said, enough to keep the blade flat on the hone. Interesting to see exactly how much pressure you are using with the scale. I have a little electronic one for mailing when I sell on ebay . I will have to give it a try.