Measuring razor blade width?

Hey - sorry if this question seems silly or obvious, but I've heard conflicting things and am trying to get a definitive answer (or at least as much as is possible, i.e. a an SRP thread): when measuring the size of a blade, do you include the width of the spine? I.e., measuring from the edge to the spine, often the "dome" of the spine adds at least another 1/16" - does that "count" toward the width? I presume there *is* some standard rule about this, but I haven't been able to find it. Thanks all.

The measurement from the top of the spine to the edge corresponds to the sizing nomenclature (6/8, 7/8 etc). If you are trying to do the math involved in figuring out the bevel angle you need the height from the edge (bevel) to the bottom edge of the honing flat.

actually there is no standard rule.
looking at new old stock razors, and i mean in untouched factory condition the official size is just an approximation of the actual width no matter how you measure it. there's a lot of variation.

Hmm. Someone pointed me to a diagram showing the two methods, though it seems my description was clear. the creator of this diagram thinks that the "old" (vintage?) way was to measure only to the "hone line" and the "new" way to measure all the way up to the top of the spine.

That is not old-vs-new that is brand-vs-brand sometimes country-vs country...

As Gugi said there is much variation even with the NOS vintage inside their stamped boxes......

Huh. I think it was Undream who made that image. Anyways, I guess there was a good reason why I couldn find a definite answer to the question ;] Oh well. Thanks guys.

Quote:

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Originally Posted by gugi

actually there is no standard rule.
looking at new old stock razors, and i mean in untouched factory condition the official size is just an approximation of the actual width no matter how you measure it. there's a lot of variation.

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There is a standard rule it was posted buy the guy just above you. The width of the blade is measured from the top of the spine to the cutting edge. The reason for variation is that France and Germany are metric countries. The blade blanks are forged in metric sizes. We adjudicate them into a close English size.

Quote:

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Originally Posted by gugi

actually there is no standard rule.
looking at new old stock razors, and i mean in untouched factory condition the official size is just an approximation of the actual width no matter how you measure it. there's a lot of variation.

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They are an approximation because they are metric blades!!!!!

I seen this brought up before John, and I do believe that it might be "Partially" correct and some of the variance could be from the metric to English conversion, but not all...
In fact this theory holds some water right up until we get to the USA, then it falls apart...
Or perhaps the theory is totally correct, but Gugi is right and there is variance in the actual manufacturing process...

But yeah the metric conversion doesn't cover it all..

Just to make sure I understand you correctly though you are saying that a French razor that is marked 7/8 is really measured to 20 or 21 mm???? so that is why it is off??

Quote:

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Originally Posted by John Crowley

There is a standard rule it was posted buy the guy just above you. The width of the blade is measured from the top of the spine to the cutting edge. The reason for variation is that France and Germany are metric countries. The blade blanks are forged in metric sizes. We adjudicate them into a close English size.

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Quote:

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Originally Posted by John Crowley

They are an approximation because they are metric blades!!!!!

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John,

This is just plain wrong! Here are two obvious reasons:
(1) When Thiers-Issard, LeGrelot, or Puma stamps 5/8 or 6/8 on the blade, that is not a metric unit! Or perhaps it's just a decoration? I'm sure being at this way longer and also being a vendor, you have seen way more razors than me, plese tell me how many razors you have seen the size of which is marked in metric units. Photographs will be wonderful if you have any.
(2) 1mm is about 0.3/8. If there was a standardized way of measuring where do the variations between (say european) manufacturers, or even within the same manufacturer come from?

Quote:

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Originally Posted by gugi

John,

This is just plain wrong! Here are two obvious reasons:
(1) When Thiers-Issard, LeGrelot, or Puma stamps 5/8 or 6/8 on the blade, that is not a metric unit! Or perhaps it's just a decoration? I'm sure being at this way longer and also being a vendor, you have seen way more razors than me, plese tell me how many razors you have seen the size of which is marked in metric units. Photographs will be wonderful if you have any.
(2) 1mm is about 0.3/8. If there was a standardized way of measuring where do the variations between (say european) manufacturers, or even within the same manufacturer come from?

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Zero point 3/8? Now that's a measurement!

:beer2:

You know, you guys can think what you want to. If you believe it is proper to shave with the spine and tape the edge when honing the handle it effects me nada!

You will see some guys that sell razors show the pictures and tell you the measurement from the back of the spine to the edge. It is difficult to come up with a standard because of the variations of the spine. For instance, a razor that is 6/8 with a flat spine would be different than a 6/8 with a rounded spine. That is where the pictures help along with measurement given.


Take Care,
Richard

Fellow retentives,

You have to give this measurement business the slack that the measurement gives itself. That being when you measure in eights you are using a rather large unit which implies a +/- accuracy of about half that unit, or 1/16". So your 6/8 razor could be about as narrow as 11/16 or as wide as 13/16, give or take a 32nd here or there.

Personally, I measure all my disinfected razors with a dial caliper and can get the width nailed down to .001". The only disadvantage there is the edge seems to suffer from my metric ministrations as my calipers have carbide faces and crush that edge pretty good. Then, of course, there is trying to figure out where to measure the width as some razors have a bit of a taper and do you use the average, tip, or heel number? Unfortunately, the tapered razors now have squeeze marks in three places along the edge.

Then when I hone them to get rid of the dents, the razors are now a bit smaller and when I measure them again, darn it, there are more of these bothersome dents. Unfortunately now, to measure the loss of overall width, which is quite small, I have to use a micrometer that can read to the tenth of a thousandth and, man, can those little C-clamps squeeze a blade, let me tell you.

:beer2: