Modular Drawer System v2 — Fully Parametric, AkroMils-Compatible

A lightweight, fully parametric modular drawer cabinet system.
Has default sizing suggestion to be compartible with fractional Akro-Mils-style bins, but designed to be reshaped to whatever bins, drawers, or layouts you actually need — without editing the CAD by hand. One OpenSCAD file generates every printable part.

✨ What's new in v2

This is a ground-up rework of my earlier Lightweight Modular Drawer System (Akro-Mils Scale). The big changes:

• 🔒 New H-lock connectors. The old diamond rivet pins are gone. They were very tricky to install, especially from the back when pliers could not reach sides to squeese pin in. Modules now join with a slide-in dovetail strip — a "H locking key" that drops into matching slits along every cell edge. Cleaner mating, no protruding pegs on the outside, easier to assemble, easier to take apart. The same locking keys are used to attach modular outer shell panels that are themself chained by dovetail keys. 
• 🛠 Fully parametric. Every dimension that matters is a top-level variable: drawer outer width / length / height, rows × columns, wall thickness, drawer-to-slot clearance, opening pattern, retention lip, front pull, lock geometry, outer-shell thickness. Hit MakerWorld's Customize button to dial in your own size — no OpenSCAD install required.
• 📦 Optional outer shell. A separate set of flat panels + butterfly keys can wrap a whole stack of modules into a single rigid cabinet. Keys are captured from the inside, so nothing pulls out from the outside. Panels are captured from sliding out by the same locking keys/slots that are used for module interconneciton.
• 🪛 Lock-strip insertion tool included. The dovetail strips are small and awkward to handle by hand. PART 4 prints a tiny paddle that holds the strip captive while you start it into the slit.
• 🕳 Smarter wall openings. Every drawer slot has chamfered octagonal cutouts on all five surrounding faces (left, right, top, bottom, back) — saves filament and weight, looks intentional, and the chamfer geometry is sized so every span prints cleanly with the back face on the bed (no supports anywhere).

⚠️ Not back-compatible with v1. Modules printed with the old diamond-rivet system will not mate with v2 modules. If you've already printed v1, finish that build out with v1 — don't try to mix them.

📐 Sizing presets

Drawer outer dimensions are the variables you set directly (DRAWER_OUTER_W, DRAWER_OUTER_L, DRAWER_OUTER_H). Common Akro-Mils-bin-equivalent values:

Set whatever else you like — these are just convenient starting points.

🧩 What you can print (PART selector)

The single .scad file outputs different pieces depending on the PART value in the customizer:

Print one PART at a time, change the value, repeat. A typical build is: N × PART 1, N × ROWS × COLS × PART 2, a handful of PART 3s, and one PART 4.

🖨 Print orientation & settings

• Case unit (PART 1): back face on the bed. The "front" of every wall ends up at print-top, so the opening geometry is sized to keep all top-edge unsupported spans under ~8 mm — prints cleanly with no supports.
• Drawer (PART 2): bottom face down.
• Lock strip (PART 3): lay it long-axis horizontal on the bed. PETG suggested due to better flexibility. Good layer adhesion is critical for this part.
• Insertion tool (PART 4): paddle face down; the cradle is a downward cut so it self-supports.
• Outer shell pieces (PART 5–10): all designed to print flat with no supports.

Tested on FDM at 0.2 mm layers, PLA/PETG. Walls default to 1 mm so a single perimeter pair gives full strength — no infill needed in case walls.

🔧 What's customizable (the big knobs)

Most useful parameters, in roughly the order you'll want to touch them:

• DRAWER_OUTER_W, DRAWER_OUTER_L, DRAWER_OUTER_H — outer drawer size in mm. If you need to accomodate specific insert tray, measure them in needed configuration, add 1mm for extra spacing and 1 mm for each wall side. outside dimensions of single drawer are starting point of the whole system.
• ROWS, COLS — grid of drawer slots per case unit
• SEP_L, SEP_W — dividers inside each drawer. Long drawers like 2x akro mils capacity might need middle separator to keep drawer sides stable.
• WALL (1 mm default), GAP (1 mm drawer-to-slot clearance per side), DRAWER_WALL. WALL will be doubled for internal separators, connected units produce doubled as well. Single outer shell can be reinforced by outer shell.
• LIP_H, LIP_D — retention click strength (drawer-front snap). This is tiny indent on drawer and tiny lip on drawer case slot to keep drawer in and resist vibration movement.
• PULL_PROTRUSION, PULL_THICKNESS — front-pull finger scoop
• OPENING_RATIO, OPENING_MARGIN, OPENING_MAX, OPENING_FLAT — wall cutout pattern
• LOCK_* — H-lock geometry (advanced; defaults are tuned, only touch for thicker walls)
• SHELL_* — outer-shell parameters (only matters if you build PART 5–10)

🛠 Assembly

1. Print the case units and drawers you need.
2. Stack/abut two modules face-to-face on whichever edge you want to join.
3. Drop a lock strip (PART 3) into the open mouth of the matching slits. Use the PART 4 insertion tool to start it — the cradle holds the tiny strip while you push it past the panel face. Flip the tool around and use the back-end dimple to seat it the rest of the way.
4. Slide drawers in. They click past a small front-bottom lip that holds them closed.

For larger builds, optionally print the outer shell (PART 5–10) and wrap the whole stack — corner beams pre-place on the inside, then panels slide over them from outside.

🙏 Credits & history

• Earlier diamond-rivet version: Lightweight Modular Drawer System (Akro-Mils Scale)
• Design rewrite, H-lock mechanism, parametric refactor: this listing.

If you build something interesting — different drawer sizes, custom layouts, weird aspect ratios — please post a Make, I want to see what people do with the parameters.

Original work. License: see listing terms. Feedback, bug reports, and Make pics very welcome — the parametric surface is large and there are corners I haven't tested at every combination.