Drawerforge

Gridfinity baseplates and bins, built to the drawer you actually have.

Drawerforge is a pair of free, open, browser-based tools for Gridfinity. Measure your drawer once, and it works out the grid, splits the baseplate to fit your print bed, joins the pieces with printable connectors, then lays out the bins that go inside — exporting STL and 3MF, including pre-arranged print plates that open straight in your slicer.

Everything runs in your browser. Nothing is uploaded, there's no account, and there's no tracking.

▶ Baseplates — drawerforge.co.uk · ▶ Bins — drawerforge.co.uk/bins · Guide

Your drawer dimensions carry between the two, in both directions, without losing your work. Kitting out a whole chest? Save each drawer by name — its baseplate and its bins together — switch between them on either page, and export them as a small design file to move them to another device.

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Baseplates

• Drawer-first workflow — start from internal dimensions; choose how leftover space becomes margins (centred, one-sided, custom per side, or left as a gap), or fill it with half cells for half-size bins
• Four split modes — Balanced, Staggered (brickwork joints so seams never line up), Fewest plates (searches split patterns to minimise print-bed loads), and Manual
• Interactive cut map — click any grid line to add or remove a cut
• Seven joint options — dovetail tabs, puzzle tabs, bowtie keys, puzzle keys, snap clips, H-clips, or none
• Key housing & insertion choices — keys in a solid floor (strongest) or inside the grid walls (no extra filament); inserted from beneath, or from above to join pieces inside the drawer, including click-locking snap clips
• Magnets & screws — pockets openable from above or below, in a full solid floor or filament-saving corner bosses
• Print plan — automatic packing onto your bed, plate count, optional stacked printing
• Exports — per-piece STL, all-plates 3MF, connector keys, bin-fit test tile, joint fit sample (four graduated clearances in one small print), and a ZIP with a README and assembly order

Bins

• Whole-drawer layout — drag across the grid to place bins, click to edit, or fill the rest automatically; coverage and leftover cells shown as you go
• Multiple layers — stack bins on bins, as many layers as fit. The layer below is ghosted for alignment, and checks catch the ways a real stack fails: overhanging an empty cell, spanning bins of different heights (it would rock), or a footprint mismatch the lip can't locate
• Per-edge walls — each of the four walls can be full, two thirds, half, a low retaining lip, or fully open. An open front makes a bin you can reach into; all four open makes a flat tray or lid
• Dividers in both directions, solid blocks, and adjustable wall and floor thickness
• Raised notes — a bin's note printed in raised letters on its label shelf, sized to the shelf, clear of its dividers and under the bin stacked on it. The page says how it will read before you print, and what it cannot print
• Magnet and screw holes in the feet, lined up with the baseplate's: press-fit magnet pockets, and M3 screw holes that bridge over them so they print without supports, at the bin's outer corners or under every cell. The README says how many magnets and screws to buy
• Stacking lips built to spec, so bins stack on each other and on any spec baseplate
• See the drawer — an optional translucent shell around the preview at the drawer's inside dimensions, with the front panel at its own height, so you can judge whether the bins suit the drawer before printing any of them. It changes nothing you download
• Honest material estimates — computed analytically at your slicer's infill, not from raw mesh volume
• Print plan and export — packs bins onto your bed, exports pre-arranged 3MF plates, or a ZIP with one STL per bin type and a README carrying the layout

Guide

Written for the questions people actually arrive with, and readable without opening either tool:

• Gridfinity for drawers — measuring and what to subtract, what to do with leftover space, choosing a joint, and which bin heights fit
• Drawer size to grid — reference tables in millimetres and inches, and where to put the remainder
• Baseplate too big for your printer? — how many cells each bed takes, why rotating diagonally never helps, and how to split and rejoin

How to use it

1. Measure your drawer internally at its tightest point and subtract 1–2 mm so the finished assembly slides in. Enter width × depth in Baseplates — in millimetres or inches; everything it makes is millimetres either way.
2. Pick your printer — common ones are listed by name — and a split mode. Fewest plates is usually the best start.
3. Choose a joint. Whatever you pick, print the joint fit sample first — four tile pairs at graduated clearances tell you in one five-minute print which fit your printer produces.
4. Export and print the baseplate.
5. Switch to Bins using the header nav. Your drawer comes with you; add its usable height.
6. Lay out your bins, add layers if you want them, and check the plate count before committing — a full drawer is a lot of filament and a lot of hours.
7. Print one bin first and check it seats before committing to the rest.

Self-hosting

The shipped app is a handful of static HTML files with no runtime build step.

1. Fork or clone this repository.
2. Enable GitHub Pages (deploy from branch, root).
3. Done — Baseplates at the root, Bins at /bins/, the guide at /guide/.

Hosting it unmodified needs nothing further. If you change it and put it in front of other people, the licence asks you to offer your users the source of your version — point the Source code link in the page footers at your own fork and that covers it. Keep the name off it (see License).

three.js and JSZip are vendored in vendor/ and served from your own origin, so a page makes no third-party request at all. Copy that directory along with the HTML. The build refuses to emit a page that references an external script or stylesheet, so a CDN URL cannot creep back in.

The site also installs as an app. Once any page has been opened over http(s), a service worker (sw.js) keeps a copy of every page and of vendor/, so the tools open with no connection at all, layout link included, and the browser offers to install it to a home screen or dock from manifest.webmanifest. Both sit at the root and have to stay there: a worker only looks after pages in its own folder and below. A page opened from a file does not use either, and works offline as it always has.

The tab icon (favicon.svg, apple-touch-icon.png), the installed app's icons (icon-192.png, icon-512.png, icon-maskable-512.png) and the picture a shared link is shown with (og-image.png) sit at the root beside the pages. The icons are linked relatively and follow a fork anywhere; the link-preview image is an absolute drawerforge.co.uk URL, as the canonical links are, because a crawler has no page to resolve a relative one against. The tab icon and the link preview are set in tools/seo.js, the app's icons and manifest in tools/app.js.

Building

index.html, bins/index.html and every page under guide/ are generated, and so are sw.js and manifest.webmanifest (from src/sw.js and tools/app.js). Edit the sources, never the built files:

file	contents
src/shared-ui/style.css	one stylesheet, both tools
src/core.js	shared geometry engine — pure JS, also runs headless in Node
src/template.html, src/ui.js	the Baseplates tool
src/bins/bin.js	bin geometry, no CSG at all
src/bins/template.html, src/bins/ui.js	the Bins tool
src/guide/*.html	the guide pages, one file each

node build.js

The build itself needs nothing but Node — it splices text. node build.js --check verifies the outputs are in sync without writing, and runs in CI. The full test suite does have dependencies, because the browser tests drive a real browser; see CONTRIBUTING.md for how to run it.

og-image.png and apple-touch-icon.png are generated too, but by a browser rather than by the build — the card carries a real render of the Bins preview. After a change you would want a shared link to show, rebuild and then run:

node tools/social-image.js

The app icons are drawn from favicon.svg the same way. After changing the favicon, run the script and then the build, because the service worker's cache name is a hash of the files it caches and the icons are among them:

node tools/app-icons.js && node build.js

The build refuses to emit output unless three checks pass, each of which has caught a shipped bug: node --check on every source; an id audit (every $('id') must exist in its template); and a display-reachability audit (anything hidden with display:none must be un-hidden somewhere, or it is dead UI).

Geometry is verified headlessly:

node test/bin-audit.js

node test/fit-check.js

Read docs/ENGINE.md before touching geometry. The CSG is fragile in specific, documented ways, and the failure mode is silently broken output rather than a crash.

How it works (for the curious)

• Socket profiles follow the published Gridfinity spec (42 mm pitch, three-part profile, 4.25 mm plate); bins follow the published bin spec, so they fit any spec baseplate.
• Each piece is built by region decomposition — every grid cell becomes a directly-constructed watertight mesh, and small convex features are subtracted as prisms, the one CSG operation that is numerically robust in a hand-rolled BSP.
• Cuts are designed to never intersect the curved socket surfaces. The bins engine uses no CSG at all — every feature is additive.
• Print-plate packing is shelf-based with rotation; Fewest plates enumerates banded split patterns and packs each candidate.
• 3MF export writes the OPC container via JSZip.

Some joint pockets intentionally leave small uncapped faces where a cut interrupts the top rim (≈20 mm² per piece, all simple planar rectangles). Every mainstream slicer's automatic mesh repair closes these.

Attribution

• Gridfinity was created by Zack Freedman (Voidstar Lab) as an open standard. These tools implement the published profiles.
• The H-clip and click-locking snap-clip connector styles were inspired by the connector system in the Gridfinity Layout Tool; the geometry here is an independent implementation adapted to unpadded spec-height plates (parts are not interchangeable between the tools).

Issues, suggestions & support

Found a bug, or want a feature? Open an issue — reports with a settings share-link attached are especially easy to act on.

If the tool saved you some time, there's a tip jar at ko-fi.com/oliver_johnson — entirely optional, always appreciated.

License

AGPL-3.0-or-later — free software, and it stays free software. Use it, fork it, self-host it, build on it. If you distribute it or run a modified version as a public service, you have to offer that version's source under the same terms.

The models you make with it are yours. Everything the tool generates — STL, 3MF, the ZIP, and the geometry in them — is explicitly excluded from the licence. Sell the files, sell the prints, sell them on Etsy at a markup. No attribution, no obligation, no share of anything. That exception is written into NOTICE rather than left to be argued about.

The name is reserved: call your fork something else, so visitors can tell whose work they are looking at. A link back is appreciated but not required.

LICENSE is the AGPL text, unaltered; NOTICE holds the two additional terms above. Every version published before NOTICE was added was MIT, and that grant is not withdrawn.