Thread: Why Honed by hand feels better

Could this have to do with why our blades feel better than theirs....you know, the commercial ones of all shapes, Mach this and that, Straights for the honing challenged etc. Notice in this patent, he describes the common practice of using wheels to grind facets or bevels. This certainly has to be part of the reason for harshness in those nasty blades. I believe most if not all commercially prepared blades rely on opposing wheels leaving a raw edge on your face. This patentener may think he has a better mousetrap, but still uses wheels, making horrid hollow bevels. This guy wants to patent what we do every blade we hone.

Description

BACKGROUND OF THE INVENTION

1. The Field of the Invention

This invention relates to novel, improved processes and apparatus for producing cutting surfaces for cutting instruments. More particularly, the present invention relates to novel, improved processes and apparatus for producing razor blades and the like.

2. Description of the Prior Art

Presently, razor blades are produced by way of continuous, [COLOR=#f26522 !important][COLOR=#f26522 !important]high-speed[/COLOR][/COLOR] mass production techniques involving a plurality of sequential abrading operations to provide the cutting surface including the cutting edge. Each abrading operation provides a facet on opposed surfaces of the cutting surface and the facet may or may not be modified by subsequent abrading operations. Normally, at least three abrading operations are required to provide the facets defining the cutting surface of the finished razor blade. The first operation is the grinding operation and involves abrading opposed surfaces of a continuous sheet of metal to provide a first or "ground" facet on opposed surfaces. Thereafter the metal sheet is subjected to a rough honing operation to provide a second facet or "rough honed facet" on the surfaces while a finish honing operation provides the cutting edge facets for opposed edge surfaces of the blade. Additional details relating to present commercial razor blade manufacturing processes and apparatus can be found in commonly owned U.S. Pat. No. 3,461,616. As disclosed there, a continuous metal strip is subjected to a grinding operation, a rough honing operation and a final honing operation which provides a convex cutting edge. U.S. Pat. No. 3,461,616 is expressly incorporated herein in its entirety by reference.

The processes and apparatus disclosed in U.S. Pat. No. 3,461,616 represent a significant advance in the high-speed, continuous manufacture of razor blades. Essentially, the disclosed processes and apparatus include the three conventional abrading operations, i.e, the grinding, rough honing and finish honing operations. In the grinding operation, one of the opposed edge surfaces of a strip of blade metal is abraded first while the other opposed surface is abraded later to provide the ground facet of the cutting surface. In both the rough and finish honing operations, the opposed surfaces are abraded substantially simultaneously since the abrading means involved includes two juxtaposed abrading wheels. The novel and distinctive feature presented in the processes and apparatus of U.S. Pat. No. 3,461,616 involves the finish honing operation. In this operation, the opposed surfaces of the blade's cutting surface providing the cutting edge is abraded with abrading means arranged and adapted to initially abrade opposed edge surfaces at a relatively high included angle and thereafter abrade the opposed edge surfaces at progressively decreasing included angles to provide curved, convex cutting edge facets on the opposed surfaces. The finish honing operation of U.S. Pat. No. 3,461,616 provides several distinct advantages in commercial razor blade manufacturing processes. The most significant advantage involves the achievement of an increase in the production rate of razor blades by about five or more times.

In the processes and apparatus of U.S. Pat. No. 3,461,616, the grinding operation has been found to be a factor having an effect on the overall efficiency of the production process. Oftentimes, the grinding operation leaves a residual wire or burr at the edge of the ground surface and removal of the wire increases wear of the abrading surfaces in the entry region of the abrading means providing the rough honed facet. Additionally, automatic monitoring and adjusting means are normally arranged between the grinding and rough honing stations to detect irregularities in the ground facets and to signal appropriate adjustments to the grind station to compensate for detected irregularities. The monitoring and adjustment means are expensive, highly sophisticated and can have a limiting effect on the production rate. Accordingly, although the processes and apparatus of U.S. Pat. No. 3,461,616 are highly efficient and cost effective, there still remains a need in the art for processes and apparatus providing maximized efficiency and cost effectiveness in the mass volume production of razor blades having high quality performance characteristics. The present invention is addressed to that need and provides an extremely effective response to it.

Originally Posted by Kingfish

This certainly has to be part of the reason for harshness in those nasty blades. I believe most if not all commercially prepared blades rely on opposing wheels leaving a raw edge on your face.

Why would the use of wheels create a harsh edge? Maybe they just don't do a good job of avoiding burrs, or maybe the teflon changes the surface effects of the blade so it cuts skin better than bare raw steel does. To say that it is because they use wheels that their blades are harsh seems like a pretty huge leap.

Originally Posted by mparker762

Why would the use of wheels create a harsh edge? Maybe they just don't do a good job of avoiding burrs, or maybe the teflon changes the surface effects of the blade so it cuts skin better than bare raw steel does. To say that it is because they use wheels that their blades are harsh seems like a pretty huge leap.

Are you joking? if not you must be correct. Exchange of ideas is good for our growth on this forum, but we should always give each other respect. Peace Wheels leave a hollow bevel behind, Maybe that was not as obvious....Edge rests on face, unsupported. Seems that this idea is a given by folks in the industry.

Originally Posted by Kingfish

Are you joking? if not you must be correct. Exchange of ideas is good for our growth on this forum, but we should always give each other respect. Peace Wheels leave a hollow bevel behind, Maybe that was not as obvious....Edge rests on face, unsupported. Seems that this idea is a given by folks in the industry.

There's a difference between disrespect for your theory and disrespect for you personally. Please don't conflate the two, as that is itself an impediment to the open exchange of ideas.

I don't believe your thesis "This certainly has to be part of the reason for harshness in those nasty blades" is particularly well supported by the evidence you've provided. This is not to say that it is wrong. But you are making a great many unsupported assumptions in the leap from "honing wheel" to "harshness", assumptions that you do not appear to have examined with any sort of rigorousness.

First, handwaving aside it is quite possible to hone a blade on a wheel and not cause any significant concavity of the bevel, especially at the microscopic scale we are discussing. If the edge of the blade is not perfectly parallel to the axis of rotation of the wheel at all times then the concavity will be reduced or even eliminated. Even if this condition is met then if there is any vibration in the blade or wheel then the concavity will be reduced or even eliminated. But there are other ways of presenting the blade to the honing wheel than the one described that may have significant advantages in a high-throughput manufacturing operation. The blade could be honed on the side of the wheel with the blade running along the plane normal to the axis of rotation. Or it could be honed on the curved surface of the wheel but travel at an angle to the axis of rotation - this potentially allows the speed of the blade in a continuous-flow manufacturing line and the speed of the wheel face to partially cancel each other out, providing a sharper edge while allowing the blade to maintain a high velocity through the honing station for improved manufacturing speed. But even assuming that the manufacturers are presenting the blade in a concavity-friendly manner, and are holding it against the wheel in a vibration-free manner, there's still the question of whether the granularity in the steel will allow it to take such a concave bevel at that microscopic level. We've seen from Verhoeven's electron microscope photos that steel at that microscopic scale exhibits both significant crystalline and plastic behavior, and it seems quite possible that steel might not be able to exhibit the nanometer-depth concavity produced by a 1-2ft honing wheel against a ca 5-10 micron wide primary bevel. Nor have you provided evidence that should such minute concavity exist that our faces could even detect it.

(Also, you can measure the angle of all of the bevels on a commercial razor blade using a laser, which implies that they're pretty planar)

Secondly, you made an assumption that concave bevel=harshness. Again, it may well be true, but I'm not willing to make the same assumption quite so freely. I'm not aware of any evidence for this myself and you have not provided any in your posts. If you have evidence to support this proposition then please provide it.

Finally, there are a whole host of other differences between commercial blades and straight razors that could explain the differences we feel. Different steels (commercial blades use some unknown flavor of stainless), different honing abrasives (probably diamond, but what grit and composition), different sharpness and consistency standards, plus the various coatings they use like various proprietary flavors of teflon, plus platinum and chrome and who-knows-what-else.

Yes there are too many variables to make a true assessment without a lot of empirical data collected and unbiased tests completed.

ie: Feather's tend to feel sharper, yet we all know they aren't necessarily sharper then a traditional straight, they just have a special Teflon coating that avoids the pulling sensation of either a less sharp razor or poor razor angle.

I would think mechanical sharpening has its advantages, consistency, accuracy if dont properly like MParker762 suggested with a laser guide etc..., but it's drawback can be that it's limited to mass production material qualities, types of steel, and ability of the grinder itself, whereas the human is only limited by his knowledge,skill set, and tools available to him/her.

I prefer the "art" of traditional shaving, the hand worked razor, etc...,but for 4 years I got a perfect bbs with a DE(manufactured edge) without a hiccup.

This isn't a call to say one is better then the other, because I would always opt for the straight over the de, in-fact I dont use a DE anymore ( havent in over a year and 1/2), but this is a "traditional" method not necessarily a "better" method for shaving.

Cheers
David

Originally Posted by mparker762

There's a difference between disrespect for your theory and disrespect for you personally. Please don't conflate the two, as that is itself an impediment to the open exchange of ideas.

I don't believe your thesis "This certainly has to be part of the reason for harshness in those nasty blades" is particularly well supported by the evidence you've provided. This is not to say that it is wrong. But you are making a great many unsupported assumptions in the leap from "honing wheel" to "harshness", assumptions that you do not appear to have examined with any sort of rigorousness.

My Dear Sir,
When I God's name did I make a thesis??I am afraid you will have to disprove what is already common knowledge in the industry. This is not my theory at all. Look if you care to or just read the above patent designed to deliberately make bevels convex. For me it is only a rediscovery of accepted practices. If you being much smarter than I find technical menutia to totaly trash the whole concept you are always right.
First, handwaving aside it is quite possible to hone a blade on a wheel and not cause any significant concavity of the bevel, especially at the microscopic scale we are discussing.
Practice what you preach, have you studied this? I suspect you say much and have losts of energy and don't get challenged enough.


If the edge of the blade is not perfectly parallel to the axis of rotation of the wheel at all times then the concavity will be reduced or even eliminated. Even if this condition is met then if there is any vibration in the blade or wheel then the concavity will be reduced or even eliminated. But there are other ways of presenting the blade to the honing wheel than the one described that may have significant advantages in a high-throughput manufacturing operation. The blade could be honed on the side of the wheel with the blade running along the plane normal to the axis of rotation. Or it could be honed on the curved surface of the wheel but travel at an angle to the axis of rotation - this potentially allows the speed of the blade in a continuous-flow manufacturing line and the speed of the wheel face to partially cancel each other out, providing a sharper edge while allowing the blade to maintain a high velocity through the honing station for improved manufacturing speed. But even assuming that the manufacturers are presenting the blade in a concavity-friendly manner, and are holding it against the wheel in a vibration-free manner, there's still the question of whether the granularity in the steel will allow it to take such a concave bevel at that microscopic level. We've seen from Verhoeven's electron microscope photos that steel at that microscopic scale exhibits both significant crystalline and plastic behavior, and it seems quite possible that steel might not be able to exhibit the nanometer-depth concavity produced by a 1-2ft honing wheel against a ca 5-10 micron wide primary bevel. Nor have you provided evidence that should such minute concavity exist that our faces could even detect it.



Sir,
Again I don't need to, you should challenge the industry itself, since you have inside information of all there trade secrets. You make many, many assumptions yet have unrelated material or no material to back up your statements.

(Also, you can measure the angle of all of the bevels on a commercial razor blade using a laser, which implies that they're pretty planar)

Sir,
Have you done this to support your critisisms of industry practice. I don't have a laser.

Secondly, you made an assumption that concave bevel=harshness. Again, it may well be true, but I'm not willing to make the same assumption quite so freely. I'm not aware of any evidence for this myself and you have not provided any in your posts. If you have evidence to support this proposition then please provide it.



Sir,
In this you totally disregard once again common practice and knowledge in industry, not my theory. Maybe they are wrong.


Finally, there are a whole host of other differences between commercial blades and straight razors that could explain the differences we feel. Different steels (commercial blades use some unknown flavor of stainless), different honing abrasives (probably diamond, but what grit and composition), different sharpness and consistency standards, plus the various coatings they use like various proprietary flavors of teflon, plus platinum and chrome and who-knows-what-else.

Sir,
All of these are variables, but common sense is more apparent to some than others. We all have value in that menutia driven men can really find that loup hole when they need one, but rarely does that build a bridge, a house or sharpen a razor. And I am sure you have more endurance for this type a menutia driven science, I like the bigger picture. Shalom

FWIW, having looked at the patent in question (Gillette, 1988), I have to say it's pretty trick. The helical honing wheels lets them use the opposing wheels to stabilize the blade during the honing operation in much the same way that the old straight razor dual-wheel grinding setups did, and by varying the diameter and grit along the helical surface they pull off both a smoothly rounded bevel and fast coarse honing and fine finish honing all in one smooth hat trick. I'm impressed.

Originally Posted by Kingfish

When I God's name did I make a thesis??

It was the point of your entire introductory paragraph. Perhaps I can be excused in believing that this was the point you were trying to make - the thesis - of your original post.

Originally Posted by Kingfish

Look if you care to or just read the above patent designed to deliberately make bevels convex.

The bevels were never concave. The new mechanism makes them smoothly convex, instead of stepwise approximations of convex (didn't we have this discussion on another threadrecently?), and it's primary purpose actually seems to be to reduce burrs and to reduce the manufacturing time.

Originally Posted by Kingfish

Again I don't need to, you should challenge the industry itself, since you have inside information of all there trade secrets. You make many, many assumptions yet have unrelated material or no material to back up your statements.

It's not a trade secret - it's in the patent you were quoting, Figure 1, "A diagrammatic side view of apparatus of present invention used in manufacturing razor blades".

Originally Posted by Kingfish

common sense is more apparent to some than others.

I was trying to be polite before, hoping you would actually take a deeper look at what you were claiming to see if your sources supported your claims. Clearly I failed.

So how's this for common sense. If you examine the PDF of the patent in question (1988, Gillette), which contains the diagrams, you will find that Fig 1 illustrates the prior-art grinding wheel setup. The razor travels along the face of the wheel at an angle - i.e. there will be no concavity using that method. If you examine the remainder of the figures for the patented invention itself you will discover that their new honing system, though wheel based, also does not run the blade parallel to the axis of rotation, and since it uses helical wheels of varying diameter, it (a) not only does not produce any concavity, but (b) it actually produces a continuously convex bevel as claimed in the text. Therefore, the harshness of the commercial blades under both the old honing system and the new one can not be due to concavity in the bevels, as there is no concavity. As such harshness cannot be due to the use of concavity from the honing wheels (the entire point of your introductory paragraph in your first post) it must be due to some other cause (the entire point of my posts since). QED

This is not "minutiae driven" or loop-holes, this is simple reading comprehension and some half-remembered high school geometry, and it is the sort of thing that builds houses, bridges, and sharpens razors.


Edit: ARGH, just realized I linked the wrong patent, the one the OP is discussing is this one (Gillette, 1966). The 1988 patent I linked to is similar, variable-diameter helical hones etc... Had both of them open in the browser and linked to the wrong one... Brings up a good point though - Gillette's been producing convex bevels for 40 years now, doesn't that falsify the thesis of this post about convex bevels being more comfortable to shave with?

Edit: Double ARGH! The 1988 patent linked above is the one the OP was quoting, the 1966 patent is the one it was referring to. Summary: The discussion above of the 1988 patent is correct, the discussion in the immediately preceeding paragraph is relevant since it discusses Gillette's previous honing system which uses similar equipment.

Keeping a level head here MP and ceding that your word power compared to mine is like David and Goliath. My OP statement was a question, not a thesis. Apparently the patent purpose is to induce convex bevel, why is that important? Why do newer manufacturing methods deliberatly make convex. From the description, it is a deliberate and desireable thing. Maybe I am misinterperating it?
Respectfully and coolled off,
Michael

Originally Posted by Kingfish

Apparently the patent purpose is to induce convex bevel, why is that important?

From the 1966(filed)/1969(issued) patent #3,461,616 referred to by the patent you were quoting in your original post:

Also, in certain razor blades, it is desirable that the thickness of the sharpened edge of the blade be minimized as a relatively thin edge appears to improve the shaveability characteristics of the blade. However, in order to provide adequate strength and durability of the blade, certain blade materials require a relatively large included angle at the ultimate tip of the sharpened edge. A particular example of such a blade material is flexible alloy steel material useful in a ribbon-type razor blade. Such steel interacts with abrading wheels in a manner that modifies the abrading characteristics of the abrading material. Accordingly, it is an object of this invention to provide novel and improved methods and apparatus for forming a sharpened edge of high quality on cutting implements and particularly on the shaving edge of a razor blade.

and this:

By employing the larger angle at the entrance end it as been found that the disturbance of the ultimate tip of the blade may be reduced particularly at the end of its contact with the honing wheels, producing a blade edge of improved quality. This feaure is particularly advantageous in the case of steel that includes alloying elements such as chromium or molybdenum, which change the interaction between the steel and the abrading wheel and the abrading characteristics of the wheel. Such a steel is the relatively soft alloy stel particularly useful for flexible blades of the type used in a ribbon-type razor. It will be understood that, while the invention has particular advantages in connection with the final honing operation on a ribbon-type razor blade, it may be used with other abrading steps in the formation of the sharpened edge of other types of razor blades and other cutting implements.

So according to this patent, it's due to the particular alloy they're using and the particular manufacturing process they're using (continuous honing of long ribbons of steel that will be later chopped into blades). I'm not entirely certain what that first sentence is referring to, whether he's talking about the distance across the bevels (in which case his point is obvious), or the size of the bevel itself (in which case it's interesting and possibly relevant to my interests).

Edit: I found an explanation for this in the '88 patent, near the end (Claim 1, pg 45) - they're talking about the width of the bevel from the edge to the back of the bevel. Now why it is important that this be short is an interesting question.


How much that has to do with our particular application I don't really know. It's possible, for instance, that the smooth convexity helps because the teflon coating applies more evenly, and not because of anything to do with the way the shape interacts with our beard or face. One bit of interest though is that their steel is a type of stainless steel, and they're saying it needs a steep angle. I need to go and measure the angle of my friodurs and other stainless razors to see what their honing angle is, and see if there's any sort of correlation. But it may be that they're just using the cheapest stainless steel they can get, and it's really soft and doesn't hone well. Or maybe they can't temper it the way it needs to be because they're also using the tempering process to bake on the teflon (Schick mentions doing it this way on their website). Just because they say chromium and molybdenum doesn't mean that's the only reason.

Also of interest: The final angle of the 1969 machinery is 28 degrees (very steep by our standards, but comparable to the Feather which accd to Tim Zowada has a 25 degree final angle).

Also there's this very interesting tidbit:

A razor blade manufactured in accordance with the invention is characterized by abrasion marks disposed parallel to one another and at an angle of at least 1 deg to the normal to the blade edge. Such blades have improved shaveability characteristics without the necessity of utilizing an additional stropping step as is commonly used to straighten and smooth edges.

As the tilt angle of the wheels is 5 degrees, I'm guessing that the reason the final scratches are at only 1 degree is because of the speed of the ribbon through the machine vs the rotational speed of the wheel. But it's interesting that they feel that even such a shallow angle on the scratches is beneficial to the shave compared to right-angle scratches, and although they don't mention it I'm curious why they didn't go with a greater angle on the scratches which they could easily do by changing the wheel or ribbon speed.

These two patents are real treasure troves btw. I'm printing them out to examine more thoroughly tonight...