: Font from old 70's American engineering schematics I am looking for a specific font used in oldish technical engineering docs (ca. 70's and earlier American electronic schematics and/or block diagrams),
I am looking for a specific font used in oldish technical engineering docs (ca. 70's and earlier American electronic schematics and/or block diagrams), and I tried to identify it online, but had not found the font's name nor a download (either free or otherwise). Strange enough for a tech font, it has ambiguity between "1" and "I", and between "0" and "O".
Many, if not all, diagrams I saw scanned online for Apollo Lunar Missions used this font, for example. Same with many old valvular (vacuum-tube), transistor and even some oldish IC (integrated circuits, chips) schematics.
I think (but I'm not sure) these schematics' texts were made with a letter-rule, a plastic band with letters/numbers bored in it. A pen following the bores' edges would then draw the letters on paper. To keep machining costs down, these rulers normally used the same shape for a zero and an "O"; a capital "R" was usually made with a "P" plus a little slant, same slant was used with "O" to form a "Q". Both uppercase "I" and "1" were usually a single vertical line.
All corners and ending caps were obviously round due to the pen being so.
I tried all online font-guessing sites except the serif one, never saw this font has lowercase characters defined and uppercase is sans-serif. No site came up with a satisfactory match. Some were close, but were very different for specific glyphs.
This is an example of the font — and overall diagram style — for an early 70's avionics microprocessor, probably used in the F-16:
If a free download is available, I won't mind!
A few things on this font, like the wide/high 'R' and the 'G' with no tail look a bit like Venus, and that would be my suggestion if you wanted a "professional" font with a similar aesthetic. But this is could be a custom design by a maker of blueprint printing equipment That's just my guess here - I don't know how these were printed or what tech was used - but it looks a little cleaner than stencilled lettering would be.
I was excited to see this question and was reading through the answers to see if anyone would mention the Leroy lettering set from Keuffel & Esser This is a topic near and dear to my heart because my grandfather was VP of Manufacturing at K&E when they introduced the Leroy system. As I heard the story, the templates came in from one source and the pens from another and he put them together as an integrated product. I am sure other manufacturers did the same but I don't know if K&E was the first.
Man, this is a blast from the past. I worked in a mapmaking company in the early 1980s. The draftsmen and -women used Leroy lettering. This was a little self-contained pantograph that traced letters routed onto a stick. As I recall, the sticks we bought from Keufel & Esser.
They scribed the letters onto coated mylar, scraping off the coating. Then the mylar got blueprinted. For high end jobs it got copied in the company's twelve by eighteen foot photographic enlarger.
We had one military job. The colonel wanted us to make a template of his signature, so we could scribe it onto every map. I think our company production manager talked him out of it by asking if we could borrow his checkbook.
A couple of intrepid souls have made FOSS computer fonts to imitate the K&E templates. But that style is inimitable.
In Germany one such font was standardized as the so-called "Normschrift" (the German WP page on this: de.wikipedia.org/wiki/Normschrift, search terms: "DIN 6776" or "ISO 3098") and there are various digital fonts based on it, such as:
From github.com/hikikomori82/osifont licensed as GPL2/LGPL2, see an online demo at hikikomori82.github.io/, modern and with support for different scripts, looks to me like this font might be even hinted
From www.peter-wiegel.de/TGL.html and www.peter-wiegel.de/TGL_0-16.html (German page, "Herunterladen" stands for "download") licensed under Creative Commons Public License (?) and SIL OFL 1.1 licenses respectively (latter is bolder, for how it looks like look at former page [center image]), older with support for Cyrillic
you might wanna check: fontzzz.com/font/10006_engineering_plot.htm
almost perfect match, just reduce the height a little and there you go.
Coniglio Sublime looks like a good digital match for that stencil, albeit with a disambiguating hook on the '1'.
DIN 17 SB isn't too far off, but its rounded letters like "C" have vertical straight sides, and the digits aren't very similar at all; it also doesn't have the slight "hand-lettered" irregularities that Sublime does.
Depending on how strict the glyph requirements are (e.g. a bar for the digit 1, common "zero" and upperase letter "O", etc.), there could be a viable option from FontSquirrel, Blogger Sans:
And to illustrate some text from the schematic:
It comes in four weights with true italics. Adding to the appeal is the cost: free (licensed by CC 4.0 intl-public). It isn't "retro", but it evokes fairly well the "look/feel" of the sample provided.
The standardized font for most CAD programs is ASME Y14.5M (not the catchiest name but it does its job):
It changes ever so slightly over the years, including differentiating 1 and I and 0 and O eventually. Search for the font by year (ex: Y14.5M-2009 is the font I have). It should be free.
Here is the link to get the modern, downloadable TTF version.
If these were lettered with ink then they used a set made by KOH-I-NOOR lettering set that had templates with the letters routed into plastic and a slot that ran the full length of the template (they came in various point sizes). You lettered using device that had three legs. I still have most of my set in my drafting table.
One was a metal fine rounded tip that would trace in the routed letter guided by the routed letters. Another was a wider styles that rested in the slot. Last it had a rapid-o-graph ink pen screwed into a rotatable arm. Rotating the arm allowed you to create italic letters. By changing pen points you could control the thickness of the lettering. You should be able to find this font if you search based on KOH-I-NOOR or RAPIDOGRAPH.
Because of the time period these are most likely hand drawn. Probably using stencil, to save time*. Using a stencil explains why 0, O, I, 1 and also the foot of R are done this way, simply they are re using the stencil to save space.
Image 1: Period engineering drawings were made with similar stencils. Stencil image courtesy of Smith Drafting stencil also available form same source.
Now it probably takes a few hours to make this font. And if you want the exact same look and feel you may not have much choice on the matter. If you can find a font that closely matches that is open source then just edit that font to fix the few things that bother you.
* Technical lettering by hand is a pain in the butt.