Category Archives: DIY

…An otherwise useless exercise in rapid prototyping.

As I continue my electronics part organization spree, I was looking for …something… reasonable for through-hole resistor storage. Resistors are a problem because there are a lot of values, once mixed they’re possible-but-irritating to distinguish, and strips of resistors are awkwardly shaped.

There are some special-purpose drawers, most of which aren’t very flexible (configured to hold exactly the E12 series, or with slots too small for the 4″ strips a lot of cheap resistors come in, or…), and many of which are enormous 3D printing projects in their own right that I didn’t feel like dealing with. There are some systems with small or card-catalog style drawers, but I don’t stock large enough quantities of resistors to invest that kind of money/space, and don’t plan to. I also looked at variations on schemes using card holding binder pages, since I really like the cheap SMT binders (link is the ones Adafruit stocks, mine are all the ubiquitous brown ones with gold-debossed Chinese text because I’m cheap), but after I bought a pack of the appropriate business card slot binder sheets I realized I’d underestimated my size requirements.

After quite a lot of looking around and stalling, the only thing that really appealed to me was cloning Zach Poff’s Edge-Labeled Baggie Method, so I did.

I added some E24 values (like 51x and 75x) that I had stocks of from one purchase or another, and a few other odd labels that I happen to have stocks of. The added labels are missing the cute little colored resistor images because I’m not sure how they were generated and it wasn’t urgent enough to spend a ton of time on – I just put the value and the band numbers on those.

I did cheap out on basically every part; I used 2mil 3×4″ baggies instead of the nice 6mil ones, and I used AmazonBasics 1 x 2-5/8 Inch labels that list themselves as compatible with Avery 5160 labels. Both of those may eventually prove to be a mistake, but for now they work and feel fine.

One thing I am looking to improve upon, I currently have them stored in an old Kroger deli meat tub, which is OK but not ideal. I don’t think I can find something that will hold them reliably and still clear the 3″ height of the drawers I’ve been packing a lot of my component assortments into, so I’m probably looking for something that will close, possibly a large-ish 3×5 card organizer.

I’ve been doing some component stocking lately, and haven’t really set up a solid storage system, so I picked up a Harbor Freight 40+1 drawer cabinet thing to manage various small size + small quantity parts.

There are slots in the drawers to take dividers, but Harbor Freight doesn’t sell them, and Akro-Mils charges a bit much – somewhere in the vicinity of $10/16pcs – for injection molded dividers that experience says don’t fit terribly well. The set of Akro-Mils drawers I use on campus for kitting out instructional labs has first-party dividers that tend to float just enough to get pins trapped under them, which leaves me less than enthusiastic about spending money on those.

I saw some folks 3D Print their own, but always feel silly 3D printing flat parts, and wanted something clear.

..So I took some measurements, ordered some 0.078″/2mm polycarbonate sheet, and CAD’d up the shape.

I did a quick parametric sketch/extrude/profile in FreeCAD 0.18, and unlike the last couple times I tried to build something in FreeCAD, the Sketch constraint system didn’t bug out, the Path workbench didn’t crash, and it posted reasonable gcode. I am very pleased by this development.

Now, it is a trivial part (rectangular, 2mm thick, 34mm tall, 50mm wide for the bottom 17mm, 51mm wide for the top 17mm), but I had earlier versions of FreeCAD fall over on similarly-trivial projects, usually in the path workbench. I’d really like to have (and be vaguely competent at using) a decent all-FOSS design flow for the router, so this is an exciting development. File here if anyone wants it.

There was the usual CNC fuckery (losing Z steps because I plunged too aggressively for the bit, tapping the Z- stop because I had the spindle raised in its clamp for working off a vise and forgot, etc.), some of which were solved by finally switching my Z axis motor to a slightly higher current since I keep having problems with running out of Z force.

Had I looked a little closer I would have noticed there are third party laser-cut acrylic dividers available for like $0.33/ea compatible with the Akro-Mils small drawer size, but if you ignore the …$1000-odd of CNC machine and tooling and the value of my time… these come out to like $0.16, so it’s not completely absurd from that angle, and it was a good tool-chain test. Also, happily, they fit significantly tighter than the Akro-Mils injection molded ones, so no trapped pins.