Thread: Honing and pressure

Originally Posted by JimBC

So how is your coworker? Hopefully that will be all your emergencys for the year.

Just talked to him yesterday. He said he's tired of sitting on his butt for 23 hours a day, has no idea when he's coming back or when he will start P.T. I'm not sure what he does with that last hour in the day.......
He's about 15 yrs younger than I with a wife and a 1 yr old, they're lucky to still have him here! I seen pictures of his vehicle (head on collision). He's a hyper active type, so I'm sure being restricted is driving him nuts!

Originally Posted by fuzzychops

Pressure is force per unit area. So, for a given force (as measured with a scale) the pressure will depend on the width of the bevel and the width of the hone. I have a razor with a 3mm wide bevel and my 2H2H is around 80 microns, so with the same force, the honing pressure on the 2H2H will be 3000/80 or 37.5 times higher. I have a 1 inch wide Coticule, so the for the same razor and same force, the pressure will be 3 times higher than for a 3 inch stone.

Forgive me for be dumb, but isn't there a difference between weight, force, and pressure? I only got 5 hours of sleep, didn't research, just asking an honest question -
The only example I can think to use is if I weigh myself whether I stand on both feet or just one I weigh the same - if I stand on one foot I'm directing more pressure to that foot, but I don't weigh anymore. I guess I'm saying I'm using a weight scale, the variable would be weight right? not force or pressure although I think we are looking at the weight as pressure....

I say lots of dumb thing's early in the morning - but this may be getting to Technical over thought? a little

Originally Posted by Trimmy72

Forgive me for be dumb, but isn't there a difference between weight, force, and pressure? I only got 5 hours of sleep, didn't research, just asking an honest question -
The only example I can think to use is if I weigh myself whether I stand on both feet or just one I weigh the same - if I stand on one foot I'm directing more pressure to that foot, but I don't weigh anymore. I guess I'm saying I'm using a weight scale, the variable would be weight right? not force or pressure although I think we are looking at the weight as pressure....

I say lots of dumb thing's early in the morning - but this may be getting to Technical over thought? a little

The scale measures force, which is equivalent to weight. There is often confusion between mass and weight - weight depends on gravity, so you weigh less on the moon, but your mass is constant. Outside of Physics class, mass and weight are usually used interchangeably.

You are correct about doubling the pressure by standing on one foot; the same force (your weight) spread over half the area (one foot instead of two). Same reason the pointy end of a pin will easily puncture your skin while the head will not (with the same force). Same reason a sharp blade will shave while a dull blade will not.

Originally Posted by fuzzychops

The scale measures force, which is equivalent to weight. There is often confusion between mass and weight - weight depends on gravity, so you weigh less on the moon, but your mass is constant. Outside of Physics class, mass and weight are usually used interchangeably.

You are correct about doubling the pressure by standing on one foot; the same force (your weight) spread over half the area (one foot instead of two). Same reason the pointy end of a pin will easily puncture your skin while the head will not (with the same force). Same reason a sharp blade will shave while a dull blade will not.

My plan is to place a hone & razor on a scale that measures the weight, and zero it out.

I think all we're looking for is a number, that someone could duplicate with a scale - just give them something to shoot for, I think if anyone else has a scale that can do this please do, I think the more people involved the better. I'm hoping to do a video this evening if not by the weekend, I hope you guys don't mind hearing cartoons in the background........

Originally Posted by Trimmy72

My plan is to place a hone & razor on a scale that measures the weight, and zero it out.

I think all we're looking for is a number, that someone could duplicate with a scale - just give them something to shoot for, I think if anyone else has a scale that can do this please do, I think the more people involved the better. I'm hoping to do a video this evening if not by the weekend, I hope you guys don't mind hearing cartoons in the background........

I expect that pressure is the key here, not simply force. I would suggest that you measure the bevel width of the razors you use for your experiment to allow comparison of pressure.

Does anyone else use more force for wider bevels and less for narrow bevels?

I don't think I'm going to measure my bevels... a wedge to a hollow ground and anything in between would be different. I think it's unrealistic, as different makes most likely would produce a slightly different angle even among the same maker, whether a wedge or a hollow ground, I'm thinking this could turn into a dog chasing it's own tail kinda thing.
I'm using a postal scale, probably a towel to help keep my postal scale dry, a razor, and a spray bottle. I'm not sure I can accomplish what some of you guys are after....I'm not an engineer, scientist or some analytical facility.

As far as pressure, wouldn't a wedge of the same width as a full hollow ground weigh more, possibly not needing as much pressure? or would it due to the size of the bevels because of their grinds? I'm thinking more, I want to get that bevel set, not grind away at it all day. And what about tape, I use tape on everything, that's how I roll....the bevel would change with the addition of that. Maybe making the wedges bevel equal to the width of the full hollows of the same width blade. Then I would think the wedge would need less pressure due to the increase in angle reducing the amount of "bevel" you are producing.

From the beginning I thought you were simply looking at if the pressure on the hone changed through out your stroke. Plain and simple. I hope that you still do this. I find just that simple experiment quite interesting. I hope you get the time to do it.

Originally Posted by RezDog

From the beginning I thought you were simply looking at if the pressure on the hone changed through out your stroke. Plain and simple. I hope that you still do this. I find just that simple experiment quite interesting. I hope you get the time to do it.

Shaun, yes I plan to keep it simple. Fuzzy apparently likes the technical side of it, and that's great I can appreciate that, but realistically not feasible in my mind with the equipment I have. I'm working with a $12 postal scale....
I think anything that would have a number, letter, or marks on some type of scale would work as long as it's reading something and giving you some kind of reference point. You could at least train yourself to be consistent.
A postal scale is cheap, and I think most people could get one, that's the only way these numbers will really mean anything to anyone else is if they use a postal scale. Otherwise it's really not going to translate or be useful to someone not using a postal scale. I guess it wouldn't have to be a postal scale as long as it measures weight...

http://www.youtube.com/watch?v=L76ue-D62Vc