thnx random textbook from 1975 such great information /j
jokes aside the book is super interesting and (mostly) awesome. the name is Engineering Graphics (Giesecke et. al, 1975) and it has SO much cool stuff about hand drafting (pretty much drawing engineering diagrams by hand) and 3d sketching and so forth. picked it up from a local booksale for exactly fifty cents. of course its age does show sometimes hehe
''huh? i don't get this...''
carbon tetrachloride was a chemical once commonly used for many applications, but that has since been discovered to be detrimental to the health (and ozone layer), not unlike asbestos. this is basically saying, if you want to erase marks on your tracing cloth—itself something quite antiquated—you simply need to rub it with a highly carcinogenic chemical.
as for “benzine” (do not confuse with benzene!), it is basically a hydrocarbon soup, many of the components of which may also be toxic!!! examples include toluene and benzene. as you may guess it is also very flammable x3
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Engineering Graphics is a great read. You may similarly enjoy The Practical Draughtsman’s Book Of Industrial Design, on a similar topic but approximately 100 years older. It’s in the public domain, so fairly easy to find a scanned copy online.
My first year of college, we were required to do all drafting by hand (on vellum, the whole nine yards), and even having CAD on our computers would be considered cheating. Having to do that work by hand really develops one’s sense of 3-dimensional space and how to convey information effectively in a way that CAD doesn’t require since it sort of just does that on one’s behalf.
When I’m reviewing design drawings at work, it’s usually immediately obvious if the engineer who drew them ever drafted by hand (usually it’s an age thing, younger engineers started in CAD programs). That’s not necessarily a knock on the CAD natives, they just convey information differently (the effort it once took to develop certain views defined where and how things were drawn) and don’t have the same sense of economy (again, a lot less effort to add information in CAD compared to by hand) in their layouts.
Edit: reformatted for readability, got a little long winded
our start was a bit more convoluted. we have been working with various CAD softwares over time, and often still do for CNC machines, notably 3d printers. but due to circumstances, we also basically have access to an entire (architectural) drafting classroom that sees no use! so so much cool stuff. nice drafting desks, hand implements ranging in age from very contemporary to being war reparations from germany—stuff that has “Made in Germany - U.S. Zone” printed on it—lots and lots of books, boxes of ames lettering guides, and this is just the stuff in the classroom itself! we didn’t want all this stuff to just sit abandoned, so we decided to learn to make use of some of it. there is so much cool technique, and given this opportunity we felt obligated to ensure it wouldn’t just be lost to time.
again, it is an architectural teaching room, so we did have to procure our own engineering scales and such. still, hand drawings are so so so satisfying. there is truly nothing like sketching out an idea, putting some dimensions to it, laying it out on a nice, big sheet of paper, lettering out all those accompanying dimensions etc., and then bringing it into reality with the lathes and vertical mills and welders and other facets of the fabrication shop.
near all the fab and design stuff we do is personal hobby, so we do stuff however we feel really. again we do use CAD not infrequently! but by hand is far more gratifying.
That’s awesome! It’s super cool you have access to some living history like that, I’m more than a little jealous. I definitely agree, there’s a real sense of accomplishment to putting together a drawing by hand, it’s an art unto itself that is rarely appreciated these days IMO.
It’s great that you’re also using those drawings to actually fabricate stuff- that’s probably the fastest and most effective way to determine whether you’re communicating sufficient and appropriate information. If you missed a dimension or callout, you might not notice unless the machinist feels charitable and asks you (many places will make assumptions and keep moving, rather than hold up production) or the end product isn’t functional in a way it needs to be (e.g. parts don’t fit together, a thread is missing, etc.). It also better informs your design, as you understand how to make the thing you’re designing and know when you’ve drawn something impossible to make. I think some of the more research-focused schools miss this, as they spend so much time on theory without any practical experience to back it up, and thereby produce engineers who are entirely disconnected from the processes they oversee or contribute to.
an engineer who has never built a car will do things that makes a mechanic curse.
a mechanic without adequate engineering knowledge (doesn’t have to be formal) will do things that make an engineer sweat.
Absolutely, drives me nuts when I see shit like bolts without wrench clearance.
carbon tet will destroy your liver, and it’s also a dogshit solvent. hexane is a replacement in some applications. if you need a better solvent, use toluene
You know it’s bad when toluene is the safer, healthier alternative
