DE sharpness compared to straights

[Brutus]

Most DE blades have wider bevel angles than typical straight razors. You can also modify the bevel angle on a straight razor.


It is easy to hone a straight razor to match the sharpness of a Feather blade (and pretty cheap too, in my opinion).

This is just not true.
As stated earlier, a feather de blade has a bevel angle of approx 24 deg.
16 to 17 deg is quite typical for straight razors.
I have two custom blades that have a bevel angle of 15 deg. There is less cutting resistance then if I use a feather de blade in a shavette.
That is even with an edge that is toned down for extra comfort.

Now see what you two did!

You destroyed one of the most cherished precepts that my addled 71 year old brain hung on to.

What’s next?
You telling me that the earth is not flat??


Seriously, I had it the other way around and was quite certain from electron microscope images which I thought I remembered that the bevel of Feather safety razor blades was more acute than 16°.
I humbly recant and ask for forgiveness.


B.

 

[abies]

This is just not true.
As stated earlier, a feather de blade has a bevel angle of approx 24 deg.
16 to 17 deg is quite typical for straight razors.
I have two custom blades that have a bevel angle of 15 deg. There is less cutting resistance then if I use a feather de blade in a shavette.
That is even with an edge that is toned down for extra comfort.

I love that website but — and I say this without meaning to sound confrontational — it's difficult for me to know what to make of it simply because the factory nature of a DE blade means it will be so much more consistent than of a straight razor.

That is, the author of that website can show me all the pictures they want of their straights, and I believe it shows what can be done with a straight, or what is typical of that author, but not what's typical of actual straights in general. The typical straight razor user isn't creating web books about the science of blade sharpness with microscopy photos.

That site *might* be representative of straights in general but it might not. Without surveying blades of straight users at random (and not just a friend, who might be similar), it's hard for me to interpret vis-a-vis typical practice.

DE blades, in contrast, come off a factory, so it's easier for me to believe there would be more homogeneity in their characteristics.

Again, no hostility, just trying to reconcile this kinda stuff with the original question of the thread — which I've seen similar versions of in several forums over the years.

 

[JPO]

That site *might* be representative of straights in general but it might not. Without surveying blades of straight users at random (and not just a friend, who might be similar), it's hard for me to interpret vis-a-vis typical practice.

I don't see how surveying random edges from different straight razor users would provide any meaningful data.

There is allot of factors that effect the cutting efficiency of any edge tool.
You can quantify some variables, bevel angle is just one of them. You need to test this is practice to be able to make an assessment.

My edges just need to be sharp enough to cut with a minimum sense of cutting resistance. I am not able to do that with a DE blade, but i have no problem achieving this with a straight razor.

 

[Mitzie]

A more realistic comparison of sharpness would be to compare carbon steel DE razor blades vs carbon steel SRs. Similarly ss DE blades with ss SRs. Different steels have different characteristics.

 

[JPO]

A more realistic comparison of sharpness would be to compare carbon steel DE razor blades vs carbon steel SRs

What is wrong with comparing stainless to stainless?

 

[Mitzie]

What is wrong with comparing stainless to stainless?

Yes, like for like

 

[Darth Scandalous]

"Carbon steel" is such a broad category on its own, I'm not sure it makes a difference. Even within the relatively narrow world of razor steels, there is a pretty broad range of characteristics; many of the affects are seen in the performance of the steel in terms of wear resistance, edge retention, etc. And yes, grain structures and carbides ultimately do impact the how sharp an edge can be made, and how it can be maintained, but within the typical geometry of a DE blade, or even a straight in the usual 17-18 degree bevel range, I don't think it matters nearly as much as it would for a blade with a bevel angle below 15 degrees.

I love that website but — and I say this without meaning to sound confrontational — it's difficult for me to know what to make of it simply because the factory nature of a DE blade means it will be so much more consistent than of a straight razor.

I think it would be interesting to know what the manufacturing tolerances for DE blades are. Intuitively they should be more consistent, and in practice they probably are, but it would be interesting to make images of several of the same brand of blade from different batches to see just how consistent they are.

When I win the lottery I'm going to invest in a scanning electron microscope and hire somebody to take pictures of blades all day.

 

[abies]

I think it would be interesting to know what the manufacturing tolerances for DE blades are. Intuitively they should be more consistent, and in practice they probably are, but it would be interesting to make images of several of the same brand of blade from different batches to see just how consistent they are.

When I win the lottery I'm going to invest in a scanning electron microscope and hire somebody to take pictures of blades all day.

Yeah I do love that website; it's extremely informative and educating. I just keep thinking of all these ways it could be expanded and made definitive with regard to typical use issues.

The material and pictures of coating alone are worth a visit for anyone who wetshaves.

Inconsistency of the same model of blade from blade to blade or batch to batch can be really underappreciated. Or rather, it's something about brands that doesn't always get discussed as much as sharpness or smoothness.

 

[Goblin]

This B&B member measured the bevel angles of several blades using an SEM.

He came up with 12° as the bevel angle for a Feather, which would explain why the longevity of Feathers is reputedly short.

As someone who likes a sharp blade, paticularly a Feather, this is one reason why my exploration into straights didn't last. With my novice honing abilities I could get a blade just about sharp enough for comfort, but inevitably the edge would deteriorate beyond what a pasted strop could recover after around 7 shaves - too much time honing for not enough time shaving.

Is it possible to get a straight razor as sharp as a DE by polishing the edge with a similarly acute bevel angle? Probably. Not by me. But even if you can reach a comparable level of sharpness, there is no reason to expect the edge to maintain that level of sharpness any longer than a fresh DE blade.

 

[Darth Scandalous]

This B&B member measured the bevel angles of several blades using an SEM.

He came up with 12° as the bevel angle for a Feather, which would explain why the longevity of Feathers is reputedly short.

As someone who likes a sharp blade, paticularly a Feather, this is one reason why my exploration into straights didn't last. With my novice honing abilities I could get a blade just about sharp enough for comfort, but inevitably the edge would deteriorate beyond what a pasted strop could recover after around 7 shaves - too much time honing for not enough time shaving.

Is it possible to get a straight razor as sharp as a DE by polishing the edge with a similarly acute bevel angle? Probably. Not by me. But even if you can reach a comparable level of sharpness, there is no reason to expect the edge to maintain that level of sharpness any longer than a fresh DE blade.

From what I can see that member didn't use a SEM. He reposted micrographs from the Science of Sharp site to back up his own measurements.

I would question the 12 degree calculation for 2 reasons.

1) there are micrographs on that site of a Feather DE overlaid with the profile of a straight which he measured at 16 degrees. While he doesn't include a calculation of the Feather's angle, it is obviously more obtuse. Link

2)12 degrees is pushing the limits of where steel can *take* an edge, let alone *hold* one under use.

 

[Goblin]

From what I can see that member didn't use a SEM. He reposted micrographs from the Science of Sharp site to back up his own measurements.

You are right. I misinterpreted what he was saying - blinded by science!

Edit: This unfortunately means I might have to have another go at honing my one remaining straight razor.

 

[ZeelandsRoem]

Is it possible to get a straight razor as sharp as a DE by polishing the edge with a similarly acute bevel angle? Probably. Not by me. But even if you can reach a comparable level of sharpness, there is no reason to expect the edge to maintain that level of sharpness any longer than a fresh DE blade.

Do you have something to back-up this statement?

 

[Goblin]

Do you have something to back-up this statement?

I can't prove a negative. Do you have reason to expect that straight razors with edges that are as keen and as sharp as DE blades (to use the Science of Sharp parlance) are more resistant to dulling than DE blades?

All other factors being equal, if the key dimensions - e.g. the angle of the bevel and keenness of the edge - are the same, the rate of deterioration and deformation of the edge caused by shaving will be broadly the same, no?

If, as suggested above, the blade of a straight razor is actually keener than a DE blade, with a more acute bevel, surely one would logically expect that edge to deteriorate more quickly?

Of course, hardness of steel would be a factor too. However, as far as I can tell the rockwell hardness of modern straight razors and DE blades is broadly similar. So, if the key dimensions of the edge are the same, and the hardness of the steel is the same, then what other factors would make the edge of a straight inherently more durable than a DE blade?

 

[Darth Scandalous]

what other factors would make the edge of a straight inherently more durable than a DE blade?

Stropping.

 

[Goblin]

Stropping.

That's not an inherent factor. You might as well say that rehoning the edge makes it more durable.

 

[Darth Scandalous]

That's not an inherent factor. You might as well say that rehoning the edge makes it more durable.

I think I misunderstood what you were getting at due to context from your earlier post.

No, all else being equal, (including alloys, heat treat and temper, etc) I can't imagine that a 16 degree-beveled straight would hold its edge better than a 20+ degree DE blade, in fact I would assume the opposite since the straight's edge is inherently less robust. And practical reality bears this out; plenty of guys get multiple shaves off DE blades where I think most all of us strop our straights after every shave.

 

[catchacoolbreeze]

Thanks, and I appreciate the point. For me straight razor shaving has a focused, meditative quality about it that I enjoy, so I am unlikely to switch, except, perhaps, in situations where time, or other factors mean I don't want to meditate. However, the question I am most interested in, is really about comparative sharpness.

The feather blade had almost no sound or resistance when lopping off the hairs. The subjective experience of these factors leads me to understand that it is waaaay sharper than my straight. I am wondering if others can routinely produce sharper blades - irrespective of the relative comfort, or subjective experience. I understand, and agree that it is only part of the equation, but for now I am interested in this one variable.

With regards to lack of sound and sharpness... I'm curious what DE razor you used?

Also - a near wedge honed properly is like a silent assassin to your whiskers. It's an experience unlike any other.

 

[catchacoolbreeze]

It would be interesting to know what the bevel angle of a Feather DE blade is.
The Feather artist club blades;
The Pro has a final bevel around 24-25 degrees while the Super Pro is 18-19 degrees.
I can get a comfortable shave quite similar to a straight razor shave with a Super Pro blade. The regular pro blades will stall on my beard.
I am not sure what the bevel angle is on a DE, but to me they feel quite similar to a pro blade in terms of cutting efficiency.
A 16 to 17 deg bevel will be sharper then a 25 deg bevel angle no matter how refined the apex is.
That is if we define sharpness as the edge width at x-distance behind the cutting edge.

The cutting efficiency will depend on allot of variables, sharpness is just one.
Cutting efficiency =sharpness, keenness, edge condition, friction coefficient along the bevel (from coating or degree of polish) etc.

If you want to compare a feather de blade to a straight razor I also think you should use it in a shavette instead of a de razor. A shallow angle might make a big difference. Not all de razor are designed to allow the same shallow angle you might use with a straight razor.

This is an interesting post as I have had the exact opposite experience. All of my pro supers were duller (and thicker) than the normal feather AC blades. Addionally, all of my feather DEs were sharper (and thinner) than any AC blade I've ever used. I also find AC blades the most uncomfortable blades made. I don't have the ability to calculate bevel angles and thickness but this is what my eyeball tells me - could be wrong.

 

[Goblin]

I think I misunderstood what you were getting at due to context from your earlier post.

No, all else being equal, (including alloys, heat treat and temper, etc) I can't imagine that a 16 degree-beveled straight would hold its edge better than a 20+ degree DE blade, in fact I would assume the opposite since the straight's edge is inherently less robust. And practical reality bears this out; plenty of guys get multiple shaves off DE blades where I think most all of us strop our straights after every shave.

This is a good point. It kind of makes me wonder just how much a strop can really do in terms of "repairing" a damaged edge. Looking at the Science of Sharp on stropping, 100 laps does appear to make a difference in terms of smoothing out micro-deformations in a fresh edge. What seems to be lacking from that site is a set of images showing how much damage a shave does to a fresh edge, and how much stropping can "bring it back". I always felt like a shave + a strop still resulted in a noticeable net reduction in overall sharpness, but perhaps my stropping just sucked!

 

[JPO]

This is an interesting post as I have had the exact opposite experience. All of my pro supers were duller (and thicker) than the normal feather AC blades. Addionally, all of my feather DEs were sharper (and thinner) than any AC blade I've ever used. I also find AC blades the most uncomfortable blades made. I don't have the ability to calculate bevel angles and thickness but this is what my eyeball tells me - could be wrong.

The bevel angle of a Pro Super blade is around 19 deg. The regular pro blade is a little more obtuse. Blade thickness has no effect on the bevel angle. These blades often have two or three bevels at different angles. So, you need to measure the final bevel angle using magnification, or get the information from the blade manufacturer.
I personally prefer to use the Proline blades in my disposable blade straight razors.
There is also a coating on these artist club blades that seems to be thicker then on regular de blades. I usually need one or two shaves before these blades peak in performance.