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Drafting Triangles


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There was some talk about drafting triangles on another topic so I thought I would add it to our tool shed. I realize it’s a pretty basic tool, but I expect many may now may never have been exposed to them these days as manual drafting is kind of gone with the rotary phone dial…

drafting triangles are super handy when cutting smaller bits (or even bigger things if you have a big ass triangle) of sheet material like stickers, paper, film, chipboard, etc. The main benefit of using them is that the larger surface area of a triangle compared to just a ruler/straight edge is it’s easy to keep the triangle firmly pushed down and not move without much pressure compared to a ruler that can have a tendency to want to swivel. Triangles also are just easy to maneuver into position and then hold there easily. I usually prefer the 45 and cut on the long end as the v of the rest of the triangle is perfect for maneuvering the triangle into place. Plus you can use them to do quick right angle cuts. If you glue or double stick tape a piece of strip wood or plastic on your cutting board you can quickly do right angle cut offs by putting you stick against the strip and the triangle on top up against the strip and slice away at 90.


They also usually have nice, crisp, perpendicular edge to keep the blade square to your work. Best to not get the triangles with beveled edges—they do this so ink does not muck up along the edge/surface interface pan but this then can make a blade tip wander a tiny bit. They are usually plex and being clear with no measurement markings it’s easy to see thru the triangle if needed for positioning. Center hole usually is beveled so you can easily slip a fingertip under the bevel to pick it up easily. Downside of being clear acrylic is they can get nicked now by a blade and then can be a wobble or catch point later, but when that happens just time to replace with a new one.

sadly cad is slowly eliminating their use for drafting and drawing so they are getting harder to find nice ones and getting expensive. The old art shop here (reasonably priced chain for students) use to have nice 4” one for like a buck or two. The only art supply places now around here are very high end and they start at like $5 and up. Cheap ones at craft places usually have bevels and not a nice, crisp edge on them. Recently found a place that has them for like $2 and reasonable shipping. For me they are like xacto knives and pencils, I know I have many around, but when I need one surprisingly they go and hide! So I keep trying to saturate the workspace in hopes of there always being one right there!






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Wow that’s very cool! Glad to hear it! Nothing like being able to use simple drafting tools to draw something up. Different mental processes.


happy to hear decent triangles are available, slowly disappearing here.



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Until Lycee (secondary education), where I learned old-fashioned technical and industrial drawing, I used a whole range of tools throughout my schooling: Brackets at 45 °, 30/60 °, compass, T-ruler, trace circles, rotring drawing table (with a rotor which allows to trace at a precise degree), etc ... examples of materials: https://www.boesner.fr/dessin/materiel-dessin/tracage-dessin-technique/


I graduated and had the best regional grade (19/20). My teacher came to my home to congratulate me by announcing: "I have good news and bad news ... your grade ... we are stopping this type of teaching, next year the students will learn to use Autocad on computer".


I do not regret anything, it will have allowed me to develop an artistic talent that I use every day to draw plans and sketches.

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7 hours ago, Matthieu said:



Until Lycee (secondary education), where I learned old-fashioned technical and industrial drawing,


Me too.


I rembered my 1-hour weekly industrial drawing, starting with a drawing of a cube with a through hole, a 3-sides standard industrial drawing top, left, right (with dotted line to show the through hole on the non-pierced faces).


At that time, we were asked to use Rotring pens filled with a very dark back ink you can't erase, thus the first drawing and lines were done with HB erasable pens thenafter, once done properly with the right scaled dimensions, covered with Rotring permanent ink.


At school, my son and my daugther were using rulers, scale protactor for measuring the right angle and triangle (long and short) in mathematics couple of years ago. 



Edited by JR East
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At to hear! Makes your Brian visualize things internally by having to make it project back and forth 2D <> 3D. I’ve worked with a few people that were hard pressed to measure and draw a line with a ruler, no kidding. A pair of architects were put on a museum conceptual design project my design partner and I were running (mainly to just do a few conceptual architectural renderings) and in their first introduction to the team/clients proudly stated that they both could not draw so all conceptual renderings would be done on CAD! Gene and I almost spit out our coffee at this! They proceeded to then basically do something that looked like a 5 year old’s refrigerator art in CAD that basically did every design idea that was developed the complete opposite! Clients horrified architects fired. I would hazard they would not know how to use a triangle.


i had two semesters of mechanical and architectural drafting in jr high school (like year eight in school) and loved it. Served me well in grad school just before the Mac came out when most figures done for scientific publications and presentation slides were all hand drawn with a triangle, French curve, and rapidograf ink pens! I did not have to pay for many beers for quite a while there! At least I got folks using rub off dry transfer lettering instead of the leroy lettering sets! That in itself was a huge improvement, but with a year the Mac wiped out 90% of that fast.


all this being said the lowly old triangle is probably the most satisfying tool for me to hold and use. Second is probably an xacto knife going hand in hand with the triangle…



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My first high school "Engineering Drawing" class standard list of tools: drawing board, T-square, 45 and 30 degree triangles, ruler, compass, pencils, and paper. We did everything with those few items.


I finished the first year's projects in just over half the the year. My teacher moved me on to the second year, and the following year allowed me to do an independent "Special Projects" class with him. He gave me an old drafting machine - the pantograph style that I used for everything after that. The teacher was a small contractor on the side and I often drew plans for him for small projects like garages and home expansions. I remember drawing a lot of roof trusses for him.


I considered architecture, but landed in engineering instead.


I gave that drafting machine to a younger work colleague a few years ago. I hadn't used it many years.



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Thanks. I wasn't aware of the difference between a "set square" with beveled edges, and a drafting square. Even in high-school when I took drafting ("Mechanical-drawing" and later "Technical drawing") we just used beveled set-squares combined with T-squares.


I think I'll add on of those to my Santa list.

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yah with pencils you dont want bevels for pencils or cutting but you need them with pens or you get capillary bleed under the square.


yes perfect for the elves to toss in your stockings. like pencils and xacto knives im surprised how these little suckers tend to dissapear! i know if bought a few dozen of the last few decades but only tossed a few due to knicks, so they are lurking somewhere. maybe the mini people are using them for clear rafters in their houses. 



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