Thread: Analysis of the Scythe and Guillotine Cuts. Spoiler: they are the same thing.

Originally Posted by JMS

Cmon Glen. You and I both know there is only one "true way" and that is a closely guarded secret among the SRP elite

As closly guarded as "The List"

The super secert list of the best shaving razors ever...

Originally Posted by basil

I have seen so many arguments about guillotine or scything motions and each has been described differently by different people.

In my opinion a video with the motions correctly described and demonstrated will help anyone reading the wiki. That way there won't be anymore confusion and arguments about the motions.

I agree entirely. This post was an attempt at movement in that direction. It may come to pass that some definitions are simply more functional than others.

As I said, I will discuss the rotating scythe cut at another time. I haven't worked anything out yet, but the sketch I have in my head suggests that the rotational scythe cut is actually less of an ideal stroke than the scythe stroke here (specifically because a razor is straight, and not curved like a scythe). However, I can't say for certain until I actually play with the mathematical model.

Again, I have no bias, I am just doing some math. Truth be told, knowing all this I still use a straight cut a fair portion of the time!

Now tell me more about this list...

Originally Posted by ixtapalapaquetl

As I said, I will discuss the rotating scythe cut at another time. I haven't worked anything out yet, but the sketch I have in my head suggests that the rotational scythe cut is actually less of an ideal stroke than the scythe stroke here (specifically because a razor is straight, and not curved like a scythe). However, I can't say for certain until I actually play with the mathematical model.

Again, I have no bias, I am just doing some math. Truth be told, knowing all this I still use a straight cut a fair portion of the time!

Now tell me more about this list...

Those are hints at something your missing

That just has to do with what you are not taking into account with blade dynamics let alone when you throw it the fact that many of us hone and strop a special way just to always keep the striations on the edge the same for a more efficient cutting edge

.

Thanks for the post. I don't know what it is called but I have found that holding the blade at a slight angle with the point above horizontal in some instances, below horizontal in others, and doing a stroke that advances, or retracts, the blade, depending on the spot, is a very effective way to shave. Slices rather than chops the whiskers. Took me a couple of years to begin to do this and there are some areas that I haven't tried it on. Definitely uses more of the length of the blade by the very nature of the stroke. Call it what you will, I consider it an advanced shaving technique, at least it was for me, so use caution if you're trying it for the first time.

Originally Posted by Utopian

OK, go ahead and do that, but the analysis can also be done with a knife and a tomato. ...everyone knows that a tomato is better cut with a slicing motion rather than a straight down motion. Shaving works the same way.

Tomayto
Tomahto

I think he has a point with the tomato...

Originally Posted by Shoki

I think he has a point with the tomato...

Ahhh but what point????

Spike point, Round point, Square point, Oblique pont, French point, Spanish point, Irish point, Hollow point, or perhaps the ole Dreadnought Point????????????

Originally Posted by ixtapalapaquetl

As I said, I will discuss the rotating scythe cut at another time. I haven't worked anything out yet, but the sketch I have in my head suggests that the rotational scythe cut is actually less of an ideal stroke than the scythe stroke here (specifically because a razor is straight, and not curved like a scythe). However, I can't say for certain until I actually play with the mathematical model.

I can say for certain.
Hold a knife over a tomato and pivot your wrist to drive the blade downward. That is what most call a scything motion. That is not an efficient cutting motion because the blade is being pushed down through the tomato without any slicing, thus it is a less ideal stroke.
That has nothing to do with how a scythe cuts. The curve of a scythe blade is shaped in a manner to match the rotational motion of a swinging scythe, with the net result being a slicing cut through the grass. That's how a scythe cuts and it's exactly the same as how a knife cuts a tomato. It's also the best way for a razor to shave, regardless of what one chooses to call it.

I would say that based on Utopians' Avatar his knowledge of shaving is suspect.....I am Teasing... I totally agree about the tomato, and was the first thing I thought of when reading the OP.

Originally Posted by Utopian

I can say for certain.
Hold a knife over a tomato and pivot your wrist to drive the blade downward. That is what most call a scything motion. That is not an efficient cutting motion because the blade is being pushed down through the tomato without any slicing, thus it is a less ideal stroke. That has nothing to do with how a scythe cuts. The curve of a scythe blade is shaped in a manner to match the rotational motion of a swinging scythe, with the net result being a slicing cut through the grass. That's how a scythe cuts and it's exactly the same as how a knife cuts a tomato. It's also the best way for a razor to shave, regardless of what one chooses to call it.

When I read your responses, there is a tone that suggests to me some sort of disagreement, but when I read more closely, I am almost certain we are saying the same thing.

My proposed tomato cutting technique is exactly the slicing motion you describe (I even made a picture in the first post - imagine a red circle instead of a brown one):



I thought I had clearly defined this as a scythe cut in the beginning of the first post - perhaps I was not clear enough. The point of this analysis was to compare this motion with the guillotine stroke, and establish that they were in reality the same. This was, at least for me, not an obvious fact until I looked at it very closely, and so I shared it.

I too think it would be inefficient to cut a tomato with a knife using a mere pivoting action. I said as much above. So if you are using the same definition of scythe as I did here why did you say I was redefining terms to meet my own... ahh nuts. I think I'll just let this go now, amigo. I guess we will have to agree to agree.