How do you draw straight lines? With a ruler or straightedge. How do you draw perpendicular or angled lines? For that you *could* do it by eye, but a drafting triangle will make the task easier. Not only that, your sketch or drawing will look a lot better too.
A local contractor’s sketch of a deck remodel reminded me of how important drafting triangles could be. Drafting triangles can be immensely useful, but it seems they’re rarely talked about outside of student or design professional circles.
Decking plans are a great example of where a drafting triangle comes in handy, since such a sketch involves a lot of parallel lines and different angles. Sure, you don’t have to add details such as board direction, but it really helps with visualizations and also setting client expectations.
The power of a quick sketch or diagram should never be taken for granted, and it’s even better if the visualization is accurate and looks good.
I’ve been using drafting triangles for more than 20 years. I started with some cheap blue triangles in high school, and they followed me around to college and then grad school. They’re a little scratched up, but I still use them.
A couple of years ago I had misplaced my student drafting triangles and ordered larger Alvin triangles in smoke gray (shown above). Well, I found my student triangles and still haven’t opened my new ones. My new ones are also larger. Maybe eventually I’ll have a drafting table (it’s been my wish for so long!), but right now small triangles work better with individual sheets of paper or my project notebooks.
You can buy a set for under $10, or you can buy them individually. It’s a mistake, in my opinion, to buy one style and not the other. A set usually comes with a 45° triangle and a 30°/60° triangle. The 45° triangle is good for splitting right angles with perfect diagonals, and the 30°/60° is great for isometric diagrams or longer verticals.
Triangles are usually used with a t-square that’s referenced along a perfectly straight table edge, giving you prefect perpendicular lines, but can also be used by eye along another reference, such as the edge of a piece of paper or a ruler mark.
There are some woodworking triangles you could use in a pinch, but moving around a thin piece of plastic over a sheet of paper is a lot easier than a chunk of metal. Plus, the transparency of drafting triangles allows for pencil (or pen) marks to show through. You can also use a fine point marker to draw temporary reference marks right on top, in case you want to space parallel lines a set distance apart from each other.
If this is something you’ve never used before, perhaps file it away under “maybe this will help me one day.” If you have used drafting triangles before, what have your experiences been like?
If you’re willing to put in some legwork, you might be able to get the best deals at art supply or craft stores. Craft stores often have 40% or 50% off coupons, making things like drawing templates cheaper to pick up locally than online. If you order online, I’ve had good experiences with Blick. Office supply stores also usually have one or two options available in-store.
With drafting triangles, bigger is not always better. When my student triangles went missing, I thought I could benefit from going with a 10″ 45° triangle and 12″ 30°/60° triangle, but they’re too big to work with on single sheets of paper unless it’s a larger page or you’re sketching on a spacious desk. I’d say that 8″ and 10″ would be better to start with for 45° and 30°/60° triangles respectively, or perhaps even smaller if working space is a concern.