Motivation is critically important in task-based learning, but acquiring a new skill from scratch can be a hard slog even when you genuinely, even urgently, need to be able to do the thing you’re trying to learn to do. The best combo is high task motivation and low task complexity — the latter measured in terms of attainability from your starting point, wherever that may be. Aim for a project that will be challenging but not too challenging and which will yield some useful result.
For years, I’d been wanting to learn CAD but knew that I’d be starting from square one and that most of my hypothetical use cases lacked immediacy (i.e. no pressing need) and were well beyond the envelope of whatever a beginner could reasonably hope to achieve before getting bogged down and throwing in the towel.
Last week, a (non-label-related) CAD-dependent project idea popped into my head and seemed as though it should be within even a from-scratch beginner’s grasp. After a bit of searching and skimming of documentation, I downloaded and installed a few currently-available open-source CAD environments, skimmed their docs, and fiddled around a bit before settling, for now, on FreeCAD. Then, I started on my idea, with some beginner tutorials on-screen and frequent pauses to search up specific information. An hour or two invested here and there on multiple days is bearing fruit. This first little CAD experiment is still in-progress, but I know I’ll be able to complete it.
Learning my way around FreeCAD (I’m still at ultra-mega-super-duper clueless greenhorn level) has had its ups and downs, but the bigger hurdles I’ve encountered have involved my naivety when it comes to obtaining accurate sub-millimeter measurements of a fairly simple real-world physical object that I’m trying to model. A couple of days ago, when some coupling nuts I’d ordered showed up, I was ready to take a breather from my intro-to-CAD project to do something even simpler: model a generic hexagonal coupling nut to produce a graphic for home-made parts labels. I could have done it as a flat illustration in a vector illustration app, but using CAD software would allow me to rotate it in space and pick a view that I found appealing and I wouldn’t have to think about or try to accurately depict perspective.
To make it as easy as possible, I gave myself permission to omit the internal threads and ignore the slight chamfering of the edges of the six corners at each end of the nut. Starting with a two-dimensional hexagon and using “pad” to extend it into three dimensions was very easy. Adding constraints, or rather figuring out what additional constraints were desired by the software, was less obvious. Attaching a circle to one face and centering it was more interesting. Turning it into a hole was a matter of a click on an icon on a specific workbench palette, but my first few attempts resulted in perfectly-centered axial holes that began some distance inside the hexagonal column.
Then came the matter of exporting a view of the model, creating an SVG or PNG that I could incorporate into a label design. There are multiple ways of producing images from FreeCAD models and I tried a few of them. Creating a
drawing, saving it as an SVG file, and using one of the vector shapes from that file was the path that I took.
I’d ordered both 304 stainless steel coupling nuts and some made of white nylon and so I elected to produce two slightly different versions of the label design. After printing them on plain paper, I cut them out, trimmed the corners, and taped them onto their corresponding clear plastic boxes (into which I’d already emptied the envelopes of nuts). The telescoping rectangular CNC tool boxes I used are cheap and easy to get from sellers on the Mainland in a range of sizes.