Akro-Mils/Harbor Freight Small Drawer Dividers (in FreeCAD)

Installed polycarbonate drawer divider, next to the CNC setup it was cut on.

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.

FreeCAD render of tool-path, with process tree visible.

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.

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