Measuring DE Blade Width with Digital Caliper and Homemade Cardstock Fixture

[ShavingByTheNumbers]

Thanks, Cal. This started with me, true, but its already a collaborative effort with your help. Thank you for your help. Oh, I thought of one more reason why "edge length" is more fitting. "Width" and "tab width" go together as the two obvious width measurements when you take width from (cutting) edge to edge. Similarly, "length" and "edge length" go together as the two obvious length measurements when you take length from tab to tab. Does that make sense? Has your mind been changed? Come on, Cal! I came around on "tab width"!

In the future, when I have enough data, I'll start the ShaveWiki page for blade dimensions that we've discussed here. The table will be sortable, so that you can reorder the rows by ascending or descending name, width, etc. There will be standard deviations, too, at least for blade width, so that we can see which blades vary more than others. Table data will be means (averages) and standard deviations with one row per blade. The blade names in the table will be links to the individual blade Wiki pages, where the individual blade sample measurements will be found, along with extra information, such as dates when the measurements were taken and when the samples were purchased. (I'm meticulous.) Quite a few blade pages already exist. I'll add to them and create new pages when necessary.

I'll post pictures of the polycarbonate fixtures after they are made. I'm still trying to settle on the best sheet thickness that's available, since I can't seem to find exactly what I want, but I'll get there. In the meantime, I am running a little experiment to determine if I can measure any difference in blade width between a new blade and a used blade. I'll post those results in due time. Even if I don't measure a difference, I will still prefer new blades for official measurements. If there is a difference, then width data for used blades will either have to be neglected or separated.

 

[TobyC]

Being a Scot I like Scottish things ).

 

[Cal]

Ah the haggis!

Fair fa' your honest, sonsie face,
Great chieftain o the puddin'-race!
Aboon them a' ye tak your place,
Painch, tripe, or thairm:
Weel are ye worthy o' a grace
As lang's my arm.

BTW [MENTION=89729]TobyC[/MENTION], I don't like your editing/rearrangement of my post above. I am not in the least embarrassed by liking Scottish things.

 

[Cal]

Thanks, Cal. This started with me, true, but its already a collaborative effort with your help. Thank you for your help. Oh, I thought of one more reason why "edge length" is more fitting. "Width" and "tab width" go together as the two obvious width measurements when you take width from (cutting) edge to edge. Similarly, "length" and "edge length" go together as the two obvious length measurements when you take length from tab to tab. Does that make sense? Has your mind been changed? Come on, Cal! I came around on "tab width"!

OK then G. This:


Additionally, a new thread from [MENTION=108562]dkeester[/MENTION] popped up which I thought might interest you: Ever had a blade not fit your DE?

 

[dkeester]

Thanks for the mention, Cal.

 

[Cal]

[MENTION=111161]ShavingByTheNumbers[/MENTION]

Not that it matters now G, but I thought you might be interested in the terminology used on the "blades" page of the Ted Pella website.

 

[Cal]

Thanks for the mention, Cal.

My pleasure Doug.

While you're here, do you have any thoughts on what [MENTION=111161]ShavingByTheNumbers[/MENTION] is doing on this thread? I thought B&B was awash with detail freaks, and apparently so... but not so many "minute detail" freaks.

 

[ShavingByTheNumbers]

I just responded to the thread by [MENTION=108562]dkeester[/MENTION] on center post width that you mentioned, Cal. I included some measurement data. Actually, I'll be updating my own thread on blade reveal parameters for the PAA DOC with caliper measurements. Keep you eyes peeled.

 

[dkeester]

Well, I am not as much of a detail freak as some, but I think creating a table of blade dimensions is a great idea. It might eventually help reduce some of the "YMMV" that surrounds blade choices.

I would happily send Grant a tuck or two of blades to help out with the effort.

 

[ShavingByTheNumbers]

Not that it matters now G, but I thought you might be interested in the terminology used on the "blades" page of the Ted Pella website.

Ahh. Interesting. They call it the "cutting edge length", but they also say "3 facet edge" and "2 facet edge" instead of "3 facet cutting edge" and "2 facet cutting edge". Nevertheless, I am open to calling it "cutting edge length". It doesn't have to be set in stone. I like their simple explanation with pictures on the differences between two- and three-fact edges. I've never read that before. It definitely explains a lot about differences in blade sharpness and life. Thanks!

 

[TobyC]

I'm hoping some will be consistently wider for use in mild razors to increase blade exposure.

 

[ShavingByTheNumbers]

OK then G. This:
View attachment 684688

Additionally, a new thread from @dkeester popped up which I thought might interest you: Ever had a blade not fit your DE?

Yes, whether I come around to calling it "cutting edge length" or not. That looks good. It's interesting that you mentioned that thread because I had previously taken some measurements with my caliper of the cutout width at the center of some used blades, but I didn't think of reporting on that data until you passed along that other thread. So, I responded to that thread with new data. I might as well ask you about what I was thinking about: We should include cutout measurements, too, right? We'll have to make names for them! Do we call it the "cutout". (That's just the word that comes to my mind right now, but is there some accepted terminology already?) There would be a "length" and a "width". There should also be "center hole width" or "center hole diameter", I think. What about the diamond-shaped cutout parts? The straight sides of the diamonds are parallel, and since that is where contact would be made with a round post, I think that the distance from straight side to straight side of the diamond shape would be the best measurement. What do you think?

 

[ShavingByTheNumbers]

Well, I am not as much of a detail freak as some, but I think creating a table of blade dimensions is a great idea. It might eventually help reduce some of the "YMMV" that surrounds blade choices.

I would happily send Grant a tuck or two of blades to help out with the effort.

That's really nice, Doug! Thanks. I might just take you up on that in the future when I have the table going and data coming in. At that point in time, measurements could be fast with a lot of blades, but starting off, they would be slow with my own blades that I'd be using for daily-or-so shaves.

 

[Cal]

We should include cutout measurements, too, right?

We'll have to make names for them! Do we call it the "cutout". (That's just the word that comes to my mind right now, but is there some accepted terminology already?) There would be a "length" and a "width". There should also be "center hole width" or "center hole diameter", I think. What about the diamond-shaped cutout parts? The straight sides of the diamonds are parallel, and since that is where contact would be made with a round post, I think that the distance from straight side to straight side of the diamond shape would be the best measurement. What do you think?

I don't know of any official terminology. I think "cutout" is good. So, following your lead I'd say good nomenclature for the internal measurements would be:

Cutout Length,
Cutout Width,
Center Hole Diameter, and
Diamond Width, like so:

Your move G.

 

[Cal]

Links to more reading matter and stuff to consider:

Basic Dimensions of a safety Double edge razor (B&B Double Edged Razors forum thread)
Blade dimensions and observations (B&B Safety Razor Blades forum thread)
Photo Analysis of 8 Brands of Razor Blades (B&B Safety Razor Blades forum thread)
Specification for Safety Razor Blades [Double-Edge] (Pakistan Standard — PS: 219-1993 [4th Rev.])

 

[skibik]

I am 8 months into DE shaving and about 5 to 6 months ago I broke out one of my calipers and started measuring the blade thickness and the distance from cutting edge to cutting edge on the blade samples I had bought after I had used them. I did this to find out why some blades felt different in the same razor, a Slim adjustable. I don't know where the info is but if memory serves correctly the thicknesses of the blades all seemed consistent where the edge to edge measurement varying a few thousandths between brands. It seemed one of my favorites, Gillette 7 o'clock Permasharp, was a little wider than my least favorite Feather. It seemed kind of odd because of how much smoother the Gillette is compared to the feel of the Feather which I would have thought would have been a touch wider due the sharper feel of the blade. I lost interest in measuring them and just went back searching for the one that feels better.

 

[ShavingByTheNumbers]

I am 8 months into DE shaving and about 5 to 6 months ago I broke out one of my calipers and started measuring the blade thickness and the distance from cutting edge to cutting edge on the blade samples I had bought after I had used them. I did this to find out why some blades felt different in the same razor, a Slim adjustable. I don't know where the info is but if memory serves correctly the thicknesses of the blades all seemed consistent where the edge to edge measurement varying a few thousandths between brands. It seemed one of my favorites, Gillette 7 o'clock Permasharp, was a little wider than my least favorite Feather. It seemed kind of odd because of how much smoother the Gillette is compared to the feel of the Feather which I would have thought would have been a touch wider due the sharper feel of the blade. I lost interest in measuring them and just went back searching for the one that feels better.

Thanks for sharing, Dean. I've found that thickness does vary a bit from blade to blade, as measured with my digital micrometer with a 0.001 mm resolution. Blade width definitely varies, and probably enough from a blade with a relatively small blade width to a blade with a relatively large blade width to significantly affect blade exposure. However, blade sharpness differences between two blades might matter more than blade width differences between the same two blades. It sounds like that is what you experienced.

 

[ShavingByTheNumbers]

Links to more reading matter and stuff to consider:

Basic Dimensions of a safety Double edge razor (B&B Double Edged Razors forum thread)
Blade dimensions and observations (B&B Safety Razor Blades forum thread)
Photo Analysis of 8 Brands of Razor Blades (B&B Safety Razor Blades forum thread)
Specification for Safety Razor Blades [Double-Edge] (Pakistan Standard — PS: 219-1993 [4th Rev.])

Thanks, Cal. I went through the links. I've seen some of that before when I researched photo analysis and blade dimensions. My favorite is the early photo analysis work by woodfluter, as reposted by Jacquers:

http://badgerandblade.com/vb/showthread.php/162987-Photo-Analysis-of-Razor-Designs/page7

Blade angle seemed to be the only parameter that was measured, with blade exposure being shown but not estimated. My photo analysis is more comprehensive, but I stand on the shoulder of giants. As far as blade dimensions go, I didn't see anything more that we could use, but I appreciate the help.

 

[CamberwellCarrot]

With this kind of detailed information about both blades and razors, the YMMV acronym might need to be retired.

 

[ShavingByTheNumbers]

I don't know of any official terminology. I think "cutout" is good. So, following your lead I'd say good nomenclature for the internal measurements would be:

Cutout Length,
Cutout Width,
Center Hole Diameter, and
Diamond Width, like so:
View attachment 684727
Your move G.

I think that we're almost there. I've looked more closely at different blades. Here are some points:

1. The straight sides of the diamond-looking part do not form right angles, as best as I can tell, so the shape should more accurately be called a "rhombus" rather than a "diamond", but a rhombus is sometimes called a diamond---I call it that---and I like using "diamond" better because who says "rhombus"? Nevertheless, the distance between the parallel sides is a good measure of the size whether the shape is square or not. I think that calling that distance the "diameter" reinforces the idea that it is the largest diameter of a circle that fits inside. However, maybe the distance should be called "height", which is the usual word when talking about the distance between the parallel sides of a parallelogram. The problem with "height", though, is that someone would probably think of the distance in the direction from cutting edge to edge from the blade diagram as being the direction of height.

2. There are really two widths to the cutout: the minimum width corresponding to the skinny part and the maximum width corresponding to the width of the keyholes---that's what I'm calling those skinny parts---and the diamond. (The keyholes and the diamonds have the same width, it appears.) Using "maximum width" could be a problem, though, if for some blade the diamond width is larger than the keyhole width. So, I now prefer sticking with "width" as the basic skinny part width and "keyhole width" as the width of the keyholes. "Diamond width" can easily be measured, too, even though it will probably be identical to "keyhole width", but they might be different.

3. Measuring keyhole length as the thickness in the blade length direction is difficult because of the rounded corners. There are no sharp corners for measuring that distance.

Here is the cutout dimensions list as I now see it:

Blade Cutout Length --- it's obvious what this is, even without a diagram
Blade Cutout Width --- very important relative to the width of blade alignment bars on razors
Blade Cutout Circle Diameter --- the diameter of the circle part of the cutout
Blade Cutout Diamond Diameter --- the diameter of a circle that fits inside the diamond parts of the cutout
Blade Cutout Diamond Width --- the width of the diamond parts of the cutout; probably identical to keyhole width
Blade Cutout Keyhole Width --- the width of the keyhole parts of the cutout; probably identical to diamond width

What do you think, Cal?