Thread: 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.

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.

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!

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?

Originally Posted by 0livia

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

Because that would be too easy!

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

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.