Thread: Angle of Attack

the science of shaving, eh?

Originally Posted by Bruno

Wrong.
By inserting an angle, you create lateral movement. If you look at it from the razor's point of view: For every mm down, you go 0.x mm sideways.
Ergo there is lateral movement. You don't perceive it because it is hidden by the fact that you move in a straight line, but the edge itself goes partially sideways.

This is what i was trying to get at.

Originally Posted by Bruno

Wrong.
By inserting an angle, you create lateral movement. If you look at it from the razor's point of view: For every mm down, you go 0.x mm sideways.
Ergo there is lateral movement. You don't perceive it because it is hidden by the fact that you move in a straight line, but the edge itself goes partially sideways.

The blade of a guillotine is supported, or firmly fixed, between two upright posts that allow the blade to travel in a downward direction only. The blade itself cannot move in any other direction. It is totally impossible without disrupting the integrity of the device. In other words breaking it. And then it wouldn't be a guillotine anymore and it wouldn't work.

The angled edge doesn't move either. As the blade travels down, it remains fixed (usually in a heavy wooden frame) in it's downward plane. It has to because of the way a guillotine is built.

The object being sliced also remains in a fixed position in space. Nothing, neither angled blade nor object being sliced, moves laterally. The angled presentation of the blade allows the cutting edge to meet the object being cut gradually, rather than all at once. This is what causes "slicing". It is an optical illusion that there might be any sideways movement of the blade. But the blade remains fixed in it's downward plane of movement.

In straight razor shaving, you are literally guillotining you beard hairs. Lateral movement of the straight razor equals cutting the skin.

Scott

Originally Posted by FiReSTaRT

I'll also make it simple: I would not want a blade to be slicing anything on my face. If you attempt a slicing motion, you better be a big fan of scars and self-mutilation. Scything motion is a different story and can come in useful with a dull blade, but if your blade is truly shave-ready it's almost redundant.

Ok, don't get confused here. You are not attempting a slicing motion. The angle of the blade as it meets the hair is what causes the slicing. The only motion you are doing is downward (this is kind of misleading because the direction of movement may not always be "downward". Hopefully the readers here are getting the idea though). The angled presentation of the blade actually does all the work.

I'm not sure if "scything" is the same thing I'm talking about, but it may be.

Once again I have proposed a conception of a technique and apparently it is very easy for some to get the wrong idea.

Believe me, I would never suggest you do anything that would deliberately cause injury. I appologize if my descriptions are hard to follow though.

Let's leave it at this: if you are interpreting anything I've suggested as dangerous, or prone to injury, assume that you have mis-interpreted or mis-understood my instructions and re-read what I wrote. Better yet, ask me to re-explain.

Re-spectfully,

Scott

Originally Posted by FiReSTaRT

In a guillotine, the blade's edge-spine plane is actually perpendicular to the neck. In a shaving equivalent it would be like having the blade absolutely parallel to the face, which would leave stubble as long as the razor's spine is thick, assuming it would cut all of the hair in a reasonable number of passes.

True, but a guillotine blade is shaped differently than a straight razor.

A guillotine blade is triangular, so even though the spine is perpendicular, the blade has an angled presentation.

Since the cutting edge of a straight razor is parallel to the spine, the shaver has to tillt the razor to get the same effect.

Scott

I think honedright is talking about drawing the razor against the face oriented like the second razor as opposed to the first.

If you draw the second razor at this angle, then the blade does indeed meet the hair like a guillotine meets the neck.

The angle of the flat of the blade off of the skin compensates for the bevel, thus presenting the edge to the hair more "head-on", wait, "head-off"? no, that's the guillotine!

Originally Posted by spacetoast

I think honedright is talking about drawing the razor against the face oriented like the second razor as opposed to the first.

If you draw the second razor at this angle, then the blade does indeed meet the hair like a guillotine meets the neck.

The angle of the flat of the blade off of the skin compensates for the bevel, thus presenting the edge to the hair more "head-on", wait, "head-off"? no, that's the guillotine!

Oh so close! Just re-orient that second razor with the point lower than the heel and then you're right on. Thank you for the illustrations. A picture is worth a thousand words.

Now the trick, as I mentioned earlier, is to maintain that relative angle throughout the shave. Just takes some practice.

Scott

Originally Posted by honedright

Oh so close! Just re-orient that second razor with the point lower than the heel and then you're right on. Thank you for the illustrations. A picture is worth a thousand words.

Scott

It seems to me that if you put some hard points in your strop that would scratch the steel and then stropped using an X pattern you would end up with scratches in line with the direction of movement of the razor assuming the razor is held like in the second picture (but with the point down). To me that indicates that stropping in a X pattern or with the heel leading is done in part to optimize shaving with the point lower than the heel.

Originally Posted by b0000urns

It seems to me that if you put some hard points in your strop that would scratch the steel and then stropped using an X pattern you would end up with scratches in line with the direction of movement of the razor assuming the razor is held like in the second picture (but with the point down). To me that indicates that stropping in a X pattern or with the heel leading is down in part to optimize shaving with the point lower than the heel.

Hmmmmm....could be??? Actually, as I picture it in my mind, I think the point is leading when I strop. Yep, I just got up off of my butt and checked, and that is what I'm doing. Point leading.

Scott

Well maybe I'm confused. I visualize it as if one strops using an X pattern, starting with the toe off the leather and ending with the heel off the leather, then the alignment would be the same as stropping in a straight line with the heel leading.
Ryan