Drafting Tools: Dividers and Compass

in #hive-168088last month (edited)

As more and more design work goes digital, fewer and fewer schools teach drafting the old-fashioned way with pen paper. I would like to offer a series of posts about my board drafting tools for those who may want to use these older techniques.


From left to right, this set includes:

  • Dividers
  • Compass (with pen adapter)
  • Original lead scribe tip with case of spares
  • Beam adapter for large radius arcs

Dividers are used to measure distances between points. Ideally, the dividers are adjusted to the length of a line on a drawing, and then held against a scale to read the measurement. In reverse, a desired length on a scale is used to set the dividers, and then they are placed on a construction line while a pencil is used to mark the endpoint. Then, a straightedge is used with a pen or pencil to draw the line. In practical use, many drafters directly measure with a scale in both instances. Perhaps I should cover scales next, or this won't make much sense. Watch for future posts in this series!

The compass quality here is higher than that of the cheap stamped metal compasses that hold a golf pencil, but I remember having problems with the joints on the compass legs slipping and messing up my work. They do, however, allow adjustment so the pen tip is perpendicular to the work surface. I should write about drafting pens and pencils at a future date, too.

The pen adapter is almost always in use when I use my compass. Swapping pens and pencils is a common task. For example, one of my pencils has blue lead that does not usually show up when a drawing is reproduced. This allows construction lines to be drawn on an original sheet without requiring erasing after the final drawing is done. Then I can switch to a pen or a pencil with dark lead to refine the segment that actually matters for the plans.


The beam compass adapter is shown above, now attached to the compass. The scribe can be moved along the length of the beam to achieve very large radii. The pen adapter could also be fitted instead of the scribe, since this set uses a common attachment system throughout. Some dedicated drafting compasses are just an adjustable beam with a fixed point at one end instead an addition to the A-frame divider-style design.

Below the compass, you can see the alternate center tip. My tools all have shouldered tips to help prevent them from making massive holes in paper should I get careless and apply too much pressure, but some drafters prefer the simpler tapered tip. I also have spare lead scribe tips and a spare tensioning knob.

The compass saw little use in architectural drafting, but mechanical drafting uses a lot of arcs to draw curved features or to construct center points for other arcs. This simple tool of ancient geometers is still used for the same kinds of work today, and if you know how to use circles and arcs to construct geometry on paper, you can easily transfer that the digital realm, too.

Please comment below if you have experience in board drafting and design, or if you have questions about anything. This is the first post in an experimental series, so clarification is doubtless necessary.

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I have a long lasting love with my father's drafting tools. He used to design water heaters in the early 70s in the Bay Area and his handwriting is still the uppercase of a drafter. I have always adored his tools. They are old school, professional grade, precision tools that make a perfect drafting line. He has them still otherwise I could get pictures. Suffice it to say I am 100% with you on this. We always need to maintain an understanding of the basics, no matter how advanced life gets.

Yeah, they trained me out of cursive writing. Now that hand lettering isn't a thing I do, I just have sloppy manuscript instead of decent cursive for my handwriting.

I also draft sewing and knitting patterns. When normal women see me cutting and sewing, they freak out a bit because instead of tissue patterns from an envelope, I am using a T-square and chalk--and a few custom dressmaker drafting tools like an armhole marker and buttonhole spacer.

That's a skill I often wish I had!

Most of the time I start with a pattern and make changes--why reinvent the armhole if I already have one that works--but for simple items I mark and cut. For example, I made Bible costumes for an entire choir simply by cutting piles of rectangles for bodies and sleeves. That is how the Bible people would have done it, after all, unless they wove the rectangles to proper size to begin with.

I took engineering graphics at Purdue (took me a bit to get caught up with the boys, because I had to take home ec. instead of shop class) and many years later taught drafting at a homeschool coop. I also use my drafting tools when I teach geometry. I am a fan of literal hands-on instruction because it opens pathways in the brain that a passive point-and-click does not. I also teach math students using engineering paper and graph paper, not graphing calculators.

Electronics and computers help you do things faster once you know what you're doing, but something about the physical activity of drawing and writing helps you learn the concept more thoroughly.

I remember taking a drafting class in high school, and was even an art major for a while in college before I changed course and got my engineering degree. Still have my good compass and many of my old art supplies, but it's been a long time since I've used anything other than just rulers, pencils, and pens. And even those I've barely used since I got my drawing tablet.

I think there's still a place for the manual methods and do think they should be taught... after all, there's not always the right hardware and/or software around. But I gotta admit, the computer (and drawing tablets!) provide so much added value for drawing (and professional drafting too I assume) that I would have students and professionals spend more time on them than on the old methods.

CAD makes it so easy to design and make changes that there is simply no comparison.

👋 Hi @jacobtothe, I was flipping through the blockchain and stumbled on your work! You've been upvoted by Sketchbook / a community for design and creativity. Looking forward to crossing paths again soon.

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