Thread: Honing Sketch

Also in recap: Jimbo thinks convex surfaces are stupid.

Your welcome, HNSB.

However, YMMV.

James.

Originally Posted by unit

I would agree that a few stroppings on micron sized compounds would make only for a very slight convex...but it is slightly convex...and after MANY repeated stroppings the edge will convex considerably.

The problem is that the lack of any quantitative measure makes such statements meaningless.

Stropping on plain leather (the mildest stropping we use) removes material from the edge and therefore adds convexity (due to the flex of the leather). But how important is this, or any other level of convexity?

But there is no need to speculate. Fortunately one doesn't need a SEM and recollection of 5th grade math to quantify these things. Our natural 'measure' of a 'significant' feature is how fast it can be 'obliterated' by a standard honing procedure.

So, let's say one does 10 laps on a pasted strop with CrO before every shave, and let's use a big strop with say ~23"x2.5" of stropping surface. This is an enormous overkill that removes metal at about 50-200 times the normal rate. You can use the razor with this procedure over a month and then check how fast you can restore the convex edge on a Norton 8000. You'll find out exactly how many laps it takes to make the bevel flat again.

And, of course, if you use Norton 4000 or even Norton 1000 the number of strokes will be orders of magnitude less, so you can quickly convert a 'significant' convexity to and 'insignificant' one by using a different honing procedure.

Originally Posted by gugi

The problem is that the lack of any quantitative measure makes such statements meaningless.

Stropping on plain leather (the mildest stropping we use) removes material from the edge and therefore adds convexity (due to the flex of the leather). But how important is this, or any other level of convexity?

But there is no need to speculate. Fortunately one doesn't need a SEM and recollection of 5th grade math to quantify these things. Our natural 'measure' of a 'significant' feature is how fast it can be 'obliterated' by a standard honing procedure.

So, let's say one does 10 laps on a pasted strop with CrO before every shave, and let's use a big strop with say ~23"x2.5" of stropping surface. This is an enormous overkill that removes metal at about 50-200 times the normal rate. You can use the razor with this procedure over a month and then check how fast you can restore the convex edge on a Norton 8000. You'll find out exactly how many laps it takes to make the bevel flat again.

And, of course, if you use Norton 4000 or even Norton 1000 the number of strokes will be orders of magnitude less, so you can quickly convert a 'significant' convexity to and 'insignificant' one by using a different honing procedure.

I agree that honing demonstrates some convexity has been imparted on almost every razor I have honed...however, it remains un-proven HOW they became convex. Do they blunt/compress over time and use?, do they deform on the strop? Do they grind convex on a loaded strop? All of the above?

Regardless, my findings/preferences (thus far) have shown preference for a nearly perfect V, that has been stopped considerably on bare leather (VVS convex?)

I have done quite a bit of testing on this over the years, this is one aspect that has continually come up...The simple reason it continues to appear is that in theory and scientifically it is true..-BUT-In practice everything falls apart, I did abusive testing on a razor with Diamond pastes considered by most to be the harshest, but after extreme over stropping and after 70+ shaves all the theroies were left hanging in the wind...That test is on the forumThe Micro-bevel and convexity ideas are easily disproved with simple honing tests, other then making honing easier they don't have any other function... Think it through, before voicing a differing opinion..Basically many of these thoeries are solid science but they having no effects in everyday use

Originally Posted by gssixgun

I have done quite a bit of testing on this over the years, this is one aspect that has continually come up...The simple reason it continues to appear is that in theory and scientifically it is true..-BUT-In practice everything falls apart, I did abusive testing on a razor with Diamond pastes considered by most to be the harshest, but after extreme over stropping and after 70+ shaves all the theroies were left hanging in the wind...That test is on the forumThe Micro-bevel and convexity ideas are easily disproved with simple honing tests, other then making honing easier they don't have any other function... Think it through, before voicing a differing opinion..Basically many of these thoeries are solid science but they having no effects in everyday use

I am not voicing a differing opinion, I am voicing different observations.

Simply put, when I return to the hones with a razor, I start with a highest possible grit to hopefully remove the least amount of metal necessary. Obviously the associated "grinding" progresses very slowly, and I am able to see the action starting at the shoulder of the bevel, and eventually sneaking up on the edge.

I am not going on record as stating how the edge achieves this shape (that I interpret to have presumably been convex)...but I do know that the honing methods are the same with regard to the tape on the spine being from the same roll.

FWIW, the 3 razors I have done this with were all razors I honed previously, and basically returned them to the hones to repair a highly localized bit of damage (touched a toe to the sink, found a very tiny chip near the heel that I cannot explain, and wanted to just check on a third that I had shaved with for a few weeks)....perhaps my stropping is to "blame", but my shaves feel great.

I hope none of this comes off as know-it-allish or argumentative. I am only sharing data, hunches, observations, and occasionally experience gained from edge work on tools other than razors. I bow to the experience and wisdom available here, but humbly share my findings and hopefully am not doing so in an arrogant tone

You are banging the hell out of the edge with every shave, it pushes the edge farther back, you strop, and draw it back out and even again.. (Microscopically)

The cycle continues over and over, I wish I could do those cool computer graphics but alas I just don't know how

As the edge gets pushed back and dulls over time, when you finally hone you have to start at the shoulder and re-define the bevel... bringing everything back down and sharp again... This would appear on the bevel as wear at only the shoulder at first until the bevel gets defined into one even sharp angle again..

Now if you were to micro-bevel you could in theory only re-define the very edge instead of the entire bevel by lifting the angle and honing over the shoulder..

Originally Posted by unit

I am not sure I understand the idea of wanting to create a convex edge on a razor...but a lot of them are these days either from stropping aggressively with abrasives or adding tape for the finish hone (Zowanda method, I think)...technically they may be more of a complex bevel than a smooth convex...but hopefully you get the point.

OTOH, I would not be quick to say convex surfaces are stupid...it is pretty easy to see that there is a bit more support behind the apex on a convexed edge and they tend to be a bit more durable in some regards (so long as they work well on your face)

Am i missing something! how can you create a convex edge from stropping aggressively or adding tape to a finished hone?
A correctly set bevel is perhaps 1mm to 2mm, adding tape to the back or spine of the razor changes the angle and does not create a convex bevel.

Originally Posted by unit

I agree that honing demonstrates some convexity has been imparted on almost every razor I have honed...however, it remains un-proven HOW they became convex. Do they blunt/compress over time and use?, do they deform on the strop? Do they grind convex on a loaded strop? All of the above?

Yes, all of the above, but to quantify each piece you need to do real science. Plastic deformation in such hardened steel is orders of magnitude smaller than the abrasive effect. You probably want to check that 1930s article on how razors dull (answer: it's oxidation/rust).

Originally Posted by unit

Regardless, my findings/preferences (thus far) have shown preference for a nearly perfect V, that has been stopped considerably on bare leather (VVS convex?)

It is possible that the preference is not the geometry of the bevel but how it's polished, i.e. if you create two very similarly convex bevels, one with a hone (and tape on the spine), and one with a pasted strop (using hard surface
and tape on the spine) would you notice the same difference. In other words by the time your bevel becomes convex through stropping between shaves there is a lot more happening to the edge. When making comparisons you want to eliminate as many of the additional effects as possible.

Originally Posted by Martin103

Am i missing something! how can you create a convex edge from stropping aggressively or adding tape to a finished hone?
A correctly set bevel is perhaps 1mm to 2mm, adding tape to the back or spine of the razor changes the angle and does not create a convex bevel.

You start with a bevel like this:
./\
/..\

When you add a piece of tape to the spine (or when you then strop on abrasive concave surface suche as a strop, or a dished out hone) you start removing metal from the very tip ending with
.^
/..\

If you look carefully you will notice that the angle at the tip (in blue) is now wider than it used to be (and still is in the red part), i.e. you have a convex curvature.

If you continue removing metal, eventually your whole bevel will become flat again as long as you use flat hone, or will match the curvature of the flexed strop/dished out hone (cf. pictures in post #4).

With my stereo microscope I have observed what appeared to be rounding of a bevel from abrasive paste on a strop.
As I think about it now, it could simply be rounding of the back side of the bevel (where the angle changes into the main part of the blade). Honing leaves a sharp transition there; an abrasive strop would no doubt put a slight radius on the corner. That could cause similar lighting effects.
I'm going to add that to my list of things to look into when I have time.