Definition of Pressure?

Since we are speaking about pressure in another thread, I think we need to come to a definiton of or a scale for what exactly "pressure" is when sharpening. To say no pressure is technically wrong, since any motion of the blade is a result of exerting force in a given direction.

I sharpen with two hands. I use my strong hand to manuver the blade while I balance the tip of the blade with my thumb and pointer fingers of my weak hand to basically keep it balanced on the stone and to keep it from lifting off the stone too early.

I would grade my "pressure" this way:
Grade 1 - this would be the least amount of pressure, basically just resting the fingers on the blade so I can feel it, but not actively pushing down on it.
Grade 2 - Using the fingers to exert a slight push, as if I placed my fingers on the computer keyboard and exerted enough pressure to jiggle the key, but not enough to press it down so that the letter is typed.
Grade 3 - Using enough pressure on the fingers to start creating some muscle tensioning in the hand. (Try pushing against the desk with your pointer finger to see what I mean.)
Grade 4 - Grade 3 description + the muscles in the forearm begin to react.
Grade 5 - Actual weight and force being exerted, which is dangerous, and will most likely end in a cut, injury or damage to the blade.

Confirmation or different definitions are welcome. If we can get a ballpark grading system, it would benefit many attempting to sharpen their own razors.

Thanks!

I don't relate to your scale. I hold the hone in one hand and the blade in the other. I usually add a little liquid soap to the water. I watch how the water flows over the blade as I move it across the hone to make sure that the blade is always in contact with the hone. Other than keeping the blade in contact with the hone, I use as little pressure as possible. I can't imagine a situation where I would go beyond your Grade 1. If a particular situation requires more laps, I do more laps. The hone is supposed to do the work, not the pressure of the blade on the hone.

When I started honing I used two hands. I have since found that using two hands applies to much pressure. To hold the blade while honing use you index finger and thumb and pinch the tang/shank so you have the top of the scales and the tang/shank. The balance should be just a little heave on the blade than the scales so the wedge end of the scales will rest on the edge of your palm. While honing raise or lower your elbow to get the blade flat on the hone. If you hold the blade with a light pinch between you fingers you will not be able to apply too much pressure. To flip the blade for the reverse lap just move you index finger up or down. This will take a little practice but I think you wil lbe pleased with the results.

Good luck.

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Originally Posted by Chimensch

I don't relate to your scale. I hold the hone in one hand and the blade in the other. I usually add a little liquid soap to the water. I watch how the water flows over the blade as I move it across the hone to make sure that the blade is always in contact with the hone. Other than keeping the blade in contact with the hone, I use as little pressure as possible. I can't imagine a situation where I would go beyond your Grade 1. If a particular situation requires more laps, I do more laps. The hone is supposed to do the work, not the pressure of the blade on the hone.

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About 3 weeks ago, I was using Grade 3 pressure, which is what I usually use for kitchen knife sharpening. The idea of this is to try to create a scale that everyone can relate to so when someone says "no pressure", or as "little pressure as possible", there is a tangible definition. Some people are heavy handed, some are not.

BTW, you just related to the scale - the red text above!

Thanks for playing!:D

I hone with one hand holding the hone, and the other holding the tang of the razor. I actually do not apply pressure to the razor per se, but I do put a variable amount of "torque" on the tang-- when I start honing I torque the edge into the hone a little bit, and let up as I progress. I use a BBW and Coticlue, and on these hones I get feedback-- it feels like suction on the blade. When I get to this point, I back off the torque, finishing with just enough force to keep the blade on the hone. Works for me!

-Chief

I'm also a hand honer, and the way I grip the tang the thumb and finger is usually pinching the top and bottom (where the jimps might be) as opposed to the sides. This means when honing (the blade being flat against the stone) I'm applying negligible pressure perpendicular to the stone and most of the 'pressure' is along the same plane as the stone -- someone mentioned torque... I'm no physicist so don't know if that's technically the correct term, but essentially I'm only using pressure to move the blade along the stone, as opposed to 'into' the stone.

Sometimes, if I want a particularly light touch, I might even use my index finger to support underneath the tang as if to lift it off the hone, but the blade stays in contact at all times. I'll do this latter technique for the final few passes on a hard coticule.

I would call that 'no pressure', since to 99% of people that would make sense. (The other 1% being engineers who might put me right! :))

The only time I use pressure is when I'm re establishing a bevel on a dull dull blade. And thats only because I've got 4 layers of tape on there and if I don't use pressure, the edge doesn't consistently contact the hone. So I use pressure to rotate the edge towards the hone. And sometimes I add a little pressure to make the process go a little faster or to cut one side quicker than the other to even out the wear.

Why don't you just do it on a scale and assign numbers to grades?

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Originally Posted by 0livia

Why don't you just do it on a scale and assign numbers to grades?

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:rant:Because that would be too easy!

Are we now to support the scale industry as well as the microscope industry?:D

I think you have a better idea than I do! BTW - Ounces or grams?

grams of course! (I'm biased, hehehe)
I'd guess 200 - 300 grams would be a good benchmark.

Back in the early '80s a barber sold me a Swaty and a coticule. He demonstrated how to hone and he taught me how to strop. He told me to use the Swaty dry and the coticule with lather or water and only the weight of the blade.

He was adamant that only three or four strokes should be used on the Swaty and not many more on the coticule. No pressure, only the weight of the blade. As a result of following my barber friends instructions I was never able to get a blade sharp or keep a sharp blade shaving well. So shortly thereafter I gave up straight razor shaving and went back to the Gillette 'Good News" for another twenty years.

Finding SRP I began to try again. I was lucky to have a forum member who lived thirty miles away and was willing to show me his honing methods. I brought a Goldedge I had gotten off of ebay and after taping the spine he started doing circles and back and forth strokes on a 1K Norton with pressure. Once the bevel was set he lightened up and moved to a 4K.

I would say that from there he used enough pressure to keep the blade flat on the hone. Lightning up as he moved up to the 8K and finally the 15K Shapton pro. I made a few more visits to my friend's house and received more instruction as I practiced with more ebay acquisitons. I have followed this procedure with good results since.

As long as you always use the same lubrication, why not just place the hone on a scale as you sharpen? You should be able to determine how much downward force is being applied by the change in weight

Sure, thats very easy to do.

Pressure = Force / Area.


The problem with this type of quantification is the human interaction itself. My results may vary when comapred to yours. Unless the force is being measured with a gage somehow ... I dont see an accurately comparable scale.

Interesting idea, though.

One way to measure it is if it is working. If your razors are getting as sharp as you want them to be without excessive or uneven wear. IOW, if it works no need to fix it. Fun to speculate though. :)

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Originally Posted by JimmyHAD

Back in the early '80s a barber sold me a Swaty and a coticule. He demonstrated how to hone and he taught me how to strop. He told me to use the Swaty dry and the coticule with lather or water and only the weight of the blade.

He was adamant that only three or four strokes should be used on the Swaty and not many more on the coticule. No pressure, only the weight of the blade. As a result of following my barber friends instructions I was never able to get a blade sharp or keep a sharp blade shaving well. So shortly thereafter I gave up straight razor shaving and went back to the Gillette 'Good News" for another twenty years.

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Is this the barber in your sig Jimmy?
:roflmao :roflmao
no wonder that didn't work improving my grip

I never go past grade 2
I also torque the tang to lift the edge sometimes on finishing strokes

when I mentioned doing circles with slurry on an escher I had my finger laid on the blade, but that isn't even enough to jiggle a key on the computer

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Originally Posted by gratewhitehuntr

Is this the barber in your sig Jimmy?
:roflmao :roflmao
no wonder that didn't work improving my grip

I never go past grade 2
I also torque the tang to lift the edge sometimes on finishing strokes

when I mentioned doing circles with slurry on an escher I had my finger laid on the blade, but that isn't even enough to jiggle a key on the computer

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No it isn't. The barber in my sig was Tom Coppetto. The barber who sold me the hones was Frank Natale. Both very old guys who cut hair into their seventies when I knew them. The thing in my sig really does work for me and has saved me from nicks/cuts many times but not every time. :)

Use lighter pressure when using finer finishing hones and heavier pressure when setting a bevel. Your forearm shouln't be cramping or anything. You're removing a very small amount of steel against a stone so there has to be some pressure. The edge gets thinner and thinner as you finish so go lighter and lighter. Use the force.

I am always a believer of less is better both in the number of strokes you use to hone as well as the amount of pressure used. I find that when using the lower grit hones for repair and bevel setting, that I do put a little more pressure on the hone than when I do the actual honing from 4K up to polishing and pasting. Because I sit at a table for stability when I hone, it is easy for me to guage pressure simply by shoulder involvement. If I sit close and have any shoulder involvement there is heavier pressure than when I sit straight and my back it against the chair with my arms in front of me for regular honing with minimum pressure.

The use of two hands on the blade has always been indicative of heavier pressure and whenever watching new guys use this method, it has been easy to identify not only too much pressure, but uneven pressure in the process.

Lynn