Lead hardness scale

Question from another website:

Is there any industry standardization of lead hardness? Is there a device or technique to measure where on the HB scale a lead falls?

Ok, it’s two questions. BOGOF!

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I seem to recall that Koh-I-Noor invented the lead hardness scale? After that everyone went along but there are differences when you compare two brands side by side.

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The hardness scale that is used for mechanical pencils is the “HB scale” but unfortunately it’s not standardized across all manufacturers.

You can read more about it here.

The best technique would be comparing HB to a #2 pencil. Won’t be very precise but that’s the rough ballpark.

German, but maybe automatic translation is readable: H und B – Lexikaliker

The origin at KIN is doubted there.

I shall outline the technique used here at Texas Graphite Lab. (Which, by the way, doesn’t really exist. It’s just me.)

Step One. Get a bunch of cheap, identical mechanical pencils. Empty them of all lead. Then, one at a time, load ’em with different brands of lead, all supposedly the same hardness grade. Each pencil should be allotted one lead, and the instant the lead is installed, you take an X-acto knife and engrave the brand and the hardness on the barrel of the pencil.

The beauty of the engraving is: You can’t really see it, while you’re writing. You have to hold the pencil up to the light a certain way to read it. That’s part of the plan.

Step Two. Write a short paragraph of meaningless gibberish with one of the pencils. Now do the same thing with another. Work through all of them, noting differences. If you do this with, like, seven different leads, you are bound to find some outrageous differences. You’ll be like “You call this H??? This is MUCH softer than these other ones anyhow…”

Step Three. Test yourself. Start to associate brands with their properties. E.g., “Squeaky? Might be Faber-Castell.” “Distinctly softer than the grade suggests? Might be Pilot.” “Makes a hissing sound? Might be Uni.” And so on. Write with a pencil, then make your guess, then check the barrel.

Upshot: You start to have an “industry average” in your head. Comes a point you can pick up any lead, vintage or otherwise, and say “Well anyhow this SHOULD be classed as 2H.” Or “This SHOULD be marked 2B.”

I want to note here that all (or prettymuch all) manufacturers of lead were simply unable to keep their own products consistent, over time. What I mean is: This 1970s thing of Sheaffer H is very, very different from this 1940s Sheaffer H. (One must also take into account the fact that any given doohicky of vintage leads—unless it’s unopened—is liable to contain random leads in it. Sometimes you can see this is the case, ’cuz there will be, like, a red lead in there with the normal ones. That should tell you something.)

At any rate, if the above does not sound fun, then at least try to remember that for some of us it totally is fun. Dreary fun—but fun.

Also it has a tendency to teach the hobbyist the ancient wisdom that all hardnesses are good, all thicknesses are good. “To every thing there is a season, and a time to every purpose under the heaven.”