The DE Razor Blade Dimensions Table is up and running!

[ShavingByTheNumbers]

I had thought that'd be the case, just hoped you'd have a tool for that. Would be interesting. Oh well...

Yeah, it is interesting. I've seen it done before online somewhere. If I remember correctly, the blade was pushed into a clay or clay-like material to make an impression, and then the impression was scanned and analyzed with a computer program.

 

[ShavingByTheNumbers]

@Tokyospike, @Hoka Hey, @Joe blow, @troy, @dangerousdon: I've looked through the list of B&B vendors at the main forum page and I found five vendors that sell several or many 100-blade items: Italian Barber, Shavetools, West Coast Shaving, Razors Direct, and Shaving.ie. Here is a proposed definition for P100:

"Price for purchase of 100 blades (USD), taken as the minimum price found among B&B vendors, Amazon, and Walmart without any consideration of shipping, and rounded to the nearest $5. eBay was not included due to price volatility."

Is that good? Should it be tweaked or changed?

 

[Tokyospike]

Well, I like it.

 

[ShavingByTheNumbers]

Check it out, guys. I've got P100 values in the comprehensive table. The P100 definition is also fixed. Please, let me know what you think. If you find something off or have a question or concern, let me have it! Thanks for your help! I couldn't have gotten here without it. I'm really glad that we've been able to get prices going.

 

[troy]

Sounds good to me.

 

[KQY61]

Hi, Stan. Thanks for your feedback, but you are mistaken. There is nothing wrong with using a standard digital or analog micrometer to measure razor blade thickness. A paper micrometer is not necessary.

As I wrote in the thread about my measurement process, which I linked to in the overview above the DE Razor Blade Dimensions Table, I'm allowing the micrometer's ratchet to handle the "feel", or force, of when to stop turning the spindle. This makes for consistent measurements, which, as stated, are made with a micrometer resolution of 0.001 mm and a reported accuracy of 0.003 mm, considered "sufficient" by me for accurate and precise measurements. I also wrote some details about the ratcheting:

"The measuring force with the friction-drive thimble is either 4 N to 7 N (0.90 lb to 1.6 lb) or 5 N to 10 N (1.1 lb to 2.2 lb) according to the calibration certificate or the manual, respectively. The ratcheting thimble allows for more repeatable, precise measurements, particularly when the micrometer is employed by someone who has not developed the light, consistent touch of an experienced user."

I prefer the consistency and simplicity of a ratcheting thimble with a digital micrometer, but an experienced user could also make consistent measurements with an analog micrometer. Either way, a standard micrometer is just fine for measuring blade thickness, as discussed in the next paragraph.

What I didn't write about in my detailed measurement process thread was how I considered deformation due to the applied pressure from the micrometer. That would have been too much detail for something so insignificant. A "paper" micrometer, or a micrometer that has larger measuring surfaces for less applied pressure, isn't necessary for measuring steel, which is considerably stiffer than paper. As stated in my measurement thread, the carbide measuring surfaces of my micrometer have diameters of about 6.47 mm (0.255 in.). Assuming the worst case of the reported measuring force as 10 N, we get a worst-case applied pressure σ = (10 N)/[(π/4)(0.00647 m)^2] = 304 kPa. The modulus of elasticity of steel is about E = 200 GPa. Correctly assuming linear elasticity here, we use Hooke's law, σ = Eε, and calculate the strain ε = σ/E = (304 kPa)/(200 GPa) = 1.521 × 10^-6. Blade thickness h generally ranges from 0.09 mm to 0.1 mm. Taking the approximate worst case of 0.1 mm for the most elastic deformation, we get a worst-case elastic displacement or change in thickness u = εh = (1.521 × 10^-6)(0.1 mm) = 1.521 × 10^-7 mm, which is orders of magnitude below the measuring resolution of 10^-3 mm.

This proves that the applied pressure from the ratcheting thimble of my digital micrometer does not throw off razor blade thickness readings. The whole point of using a ratcheting thimble is to greatly reduce measurement subjectivity from the user who would otherwise be solely responsible for feeling when or where the spindle should stop. Also important for correct micrometer measurements of a razor blade are clean measuring surfaces and a clean blade, which were discussed in my measurement process thread.

As supporting evidence that my measurements are correct or sufficiently accurate, Feather and Kai state that their blade thicknesses are "0.1" mm and "0.10" mm, respectively. For the four Feather blades that I've measured, the result is an average thickness of 0.101 mm, and for the sixteen Kai blades that I've measured, the result is an average thickness of 0.100 mm. I could be mistaken, but I believe that standard razor blade strip steel is either just about 0.1 mm thick or less than that. The Swedish manufacturer Sandvik, for example, makes razor blade strip steel in two thicknesses: 0.099 mm and 0.076 mm.

Hi,

Well, I had a long retort in mind, but I will just leave it lay. It really doesn't matter. The end result will be Good Enough regardless.

Stan

 

[ShavingByTheNumbers]

Sounds good to me.

Cool.

 

[ShavingByTheNumbers]

Hi,

Well, I had a long retort in mind, but I will just leave it lay. It really doesn't matter. The end result will be Good Enough regardless.

Stan

Your opinion does matter, Stan. Your definitive statement that I was using the wrong tool, that I needed to use a paper micrometer instead of a regular one, was surprising, though. I feel like I went on too long in defense of my measurement method. Some things that I wrote might have come across as offensive, when I was adding extra information and explanation for those that don't know certain things because it's outside of their area, so I hope that you didn't take offense, because I didn't mean any. I hope that your definition of "Good Enough" here matches mine because I don't want to redo measurements with another piece of equipment that I don't have. Would I rather be poked in the eye with a stick? Maybe, as long as the damage was temporary. If you have evidence that I'm off on something here, then please share it because I wouldn't want to continue in error. Thanks.

 

[KQY61]

Hi,

I didn't wish to derail the thread into a long winded discussion about micrometers and such. I probably ought not to have brought it up in the first place. I was reading along and the 'wrong tool' thought popped into my head, so I posted. Of course, you don't have one, and don't really want to buy one. I have one or two around, so I would have simply grabbed one.

The issue is that the shim stock thickness metal has a certain spring characteristic. So, the smaller anvil of a standard one inch mike can compress the metal and lead to a reading that is too thin. Being springy in nature, the metal doesn't deform, so one doesn't see that it occurred. For what you are measuring, you can easily be half a thousandth off. Maybe as much as three-quarters depending on the individual alloy.

Using a very light touch will mitigate this, but then you need to operate the mic by feel, not with the ratcheting knob. A light touch requires experience, so in most cases you are probably better off using that ratchet.

The paper mikes are smaller units with smaller non-ratcheting knob and a larger anvil surface area to help prevent spring compression of shim stock thickness material. So, they are a tool specifically for measuring this sort of material. They are called paper mikes because that is the industry which buys the bulk of these mikes. So, that is what they are listed as in the catalogs.

Of course, there are hundreds of specialized micrometers out there. I have dozens of different ones myself. All tools for specific uses.

But, we are not making anything here. So, being off by a little really does not matter. On the professional side, being off by half a thou given what is being measured would be on the order of 25%. That is bad. But, what is really wanted here is a relative measurement for a table, and if one uses the same kind of tool in the same manner, then those readings will be relative. And, that is good enough.

I am used to making things based on measurements, and if they are off that means at least some wasted time. It might mean wasted money. Lots of wasted money.

But, nothing is being made here, so it ought to be good enough.

And, there is a short version of what originally was formed much longer.

Stan

 

[ShavingByTheNumbers]

Hey, Stan (@KQY61). Thanks for getting back to me and detailing your concerns. Wow! You have a lot of micrometers and a lot of experience. You should know that my micrometer is my ONLY ONE. I bought it specifically for measuring blade thickness and possibly for measuring other small distances. I also bought my caliper for measuring blade dimensions, so, I don't have the tools and experience that you do, but I do have good engineering experience, which I'm trying to apply here. You're right that if I had a paper micrometer, I'd use it, but I bought a normal micrometer having a normal measuring face diameter, which has the advantage of allowing me to measure blade thickness at various locations. When I got the micrometer, I didn't know what I was going to find, so going with a regular micrometer that allowed more flexibility seemed right. I understand that a paper micrometer might work better, but I hope that I can convince you that my measurements are accurate and precise with my regular micrometer.

I conducted a test with a Kai blade and my micrometer to quantify the difference between the lightest touch and a ratcheted result. The blade and micrometer were clean. With the micrometer ratcheted closed and calibrated to 0.000 mm, I opened it up a bit and turned the thimble slowly until I started to feel something. I did this several times. The result of my lightest touch was generally 0.006 mm. Then, I ratcheted the calibrated micrometer closed on a Kai blade, yielding 0.100 mm, which is consistent with the officially reported "0.10" mm thickness from Kai. I then opened up the micrometer a bit and used my lightest touch to slowly turn the knob and stop when I felt the slightest resistance. I repeated this step a few times. I got readings from 0.102 mm to 0.105 mm. My lightest touch resulted in readings that varied by 0.003 mm. Ratcheted thimble readings varied by 0.000 mm since they were consistently 0.100 mm.

Now, with the lightest-touch and ratcheted thimble results done, I moved on to the ridiculous extreme of turning the non-ratcheting smaller knob as tightly as I could. I really clamped down on the blade! The result was a reading of 0.085 mm, but I know that this reading isn't accurate at all. It's way, way off. It's bogus. The steel would have had to have been plastically deformed and failed under the pressure to yield such a distance. Sure enough, no plastic deformation happened, as proven by a ratcheted reading afterwards of 0.100 mm. Displacement within the threads of the micrometer caused the bogus reading, and I'm sure that you knew that, but it was new to me.

Did this example convince you that blade thickness measurements with my ratcheting micrometer are precise and accurate? You were spot on about how measurements are relative to the tool, so my readings are at least relative to one another and help establish which blades are thinner or thicker than others. (I think that I've written about this somewhere.) However, I wanted to do better than that. I want precision and accuracy, and I think that I'm getting that. The micrometer's precision of 0.001 mm and reported accuracy of 0.003 mm seems to be holding up. Actually, I think that the accuracy that I'm getting is much better than 0.003 mm. First of all, according to the calibration certificate, the micrometer exhibited zero deviation in all six measurements of gauge blocks from 0.10000 in. to 1.00000 in. Secondly, I see great repeatability/consistency with the ratcheting action, I'm averaging thickness measurements over many blade samples, and the little available data from Kai and Feather match my measurements, but I'd have to do a lot of testing with traceable gauges (that I don't have) to prove accuracy for blade thicknesses ranging from 0.09 mm to 0.1 mm.

What do you think? Have I convinced you that my measurements are precise and accurate?

 

[KQY61]

Hi,

Yup. Carry on.

Stan

 

[ShavingByTheNumbers]

Hi,

Yup. Carry on.

Stan

Great! Will do!

 

[Cal]

Yup. Carry on.

Great! Will do!

Thank heavens for that! Posts back down to a level that I can understand.

 

[Joe blow]

Only my opinion: I see the proverbial can of worms being opened regarding determining pricing parameters. My opinion is that since you and you alone are doing 100% of the work getting this chart up and running that you and you alone should have total power over decisions, after all this is your baby!!!! we appreciate all your input, Bravo !!!

 

[ShavingByTheNumbers]

Only my opinion: I see the proverbial can of worms being opened regarding determining pricing parameters. My opinion is that since you and you alone are doing 100% of the work getting this chart up and running that you and you alone should have total power over decisions, after all this is your baby!!!! we appreciate all your input, Bravo !!!

Thanks, Joe. Yes, prices change, and I'm the one that will update them, but I plan on updating them infrequently. Since prices in the comprehensive table are approximate to the nearest $5 are don't include eBay, prices should be fairly stable for a good while. (One month? Two months? Several months? A year? I don't know.) For the time being, as the table grows with more blades, I will keep adding prices, of course. However, maybe in the far future, there might come a time when I pass the reigns, or they naturally pass, to others here to make edits. If the price information ever becomes bad, then it should be updated or removed. It isn't necessary information, but it is great information as long as it's correct.

 

[Fairwind]

Got 2 vintage Gillettes last week and couldn't wait for blades to come in, first DE razor in 30+ years. So I went to WM and got a tuck of VDH blades - it's all they had. The2 razors come from the same year, 1947 Aristocrat and a 47 Milord. The blade fit the Milord perfectly but wouldn't go on the Aristocrat.

Is it possible it's just the blade cutout or is it the cutout ends on the Aristocrat are wider apart either by design or maybe bent outwards a bit?

 

[ShavingByTheNumbers]

Got 2 vintage Gillettes last week and couldn't wait for blades to come in, first DE razor in 30+ years. So I went to WM and got a tuck of VDH blades - it's all they had. The2 razors come from the same year, 1947 Aristocrat and a 47 Milord. The blade fit the Milord perfectly but wouldn't go on the Aristocrat.

Is it possible it's just the blade cutout or is it the cutout ends on the Aristocrat are wider apart either by design or maybe bent outwards a bit?

I don't know, Dan. Sorry. Can anyone here help Dan with his question? Does the Aristocrat have an issue with modern DE razor blades, or is there an issue with the VDH blade because of an abnormal cutout?

 

[Brenton1979]

Check it out, guys. I've got P100 values in the comprehensive table. The P100 definition is also fixed. Please, let me know what you think. If you find something off or have a question or concern, let me have it! Thanks for your help! I couldn't have gotten here without it. I'm really glad that we've been able to get prices going. [emoji106]

I can't seem to get to your table page. When I click the link it just brings me back the the b&b homepage. I also tried to find the shave wiki but can't find that either. Can you point me in the right direction?

Sent from my LG-H873 using Tapatalk

 

[Fairwind]

Problem solved - just use Gillette blades thanks

 

[ShavingByTheNumbers]

I can't seem to get to your table page. When I click the link it just brings me back the the b&b homepage. I also tried to find the shave wiki but can't find that either. Can you point me in the right direction?

Sent from my LG-H873 using Tapatalk

Here is the link:

Comprehensive Double-Edge (DE) Razor Blade Data Table

I just tried it and it worked.