Gridfinity explained: the 42 mm grid, bins, baseplates and magnets

Everything in Gridfinity is measured in grid units of 42 mm. A baseplate cell is 42 × 42 mm, and a bin that is two cells wide and three deep occupies an 84 × 126 mm area of the grid.

Bins are made slightly smaller than the grid so they drop in and lift out easily. With the usual clearance of 0.25 mm per side, a bin’s outer size is 42 × n − 0.5 mm:

Heights are counted in units of 7 mm, written as “u”. A 3u bin is a shallow tray for small parts; 6u suits taller tools. Most bins add a stacking lip on top so another bin can sit on it, which makes the printed part a few millimetres taller than the unit count suggests. In our Gridfinity-compatible bin pack, a 3u bin is 24.9 mm tall and a 6u bin 45.9 mm, both including the lip.

When planning a drawer, measure its inside height and subtract a few millimetres for the baseplate (about 4.5 mm for a thin open-bottom frame) and for clearance above the bins.

• The foot: each grid cell has a stepped, chamfered foot underneath. It drops into the matching pocket in the baseplate and centres the bin. The profile is standardised, which is what makes designs from different people compatible.
• Walls and floor: thin walls (often around 1 mm) keep print times short; a solid floor stops small parts falling into the foot cavities.
• Stacking lip: the shaped rim at the top that lets bins stack on each other.
• Optional extras: label tabs, scoops for picking up small parts, internal dividers, and magnet or screw holes in the feet.

Baseplates come in a few common styles:

• Open-bottom (“lite”) frames: just the grid of pockets. Fast to print and light on filament; our pack includes 3 × 3 (126 mm) and 4 × 4 (168 mm) frames of this type.
• Magnet baseplates: thicker plates with pockets for magnets under each cell, so magnet bins snap firmly into place.
• Weighted baseplates: plates with cavities for coins or steel weights, so a desk grid doesn’t slide around.

Fitting baseplates to your printer

Baseplates are usually printed in pieces that sit side by side. The largest square plate you can print depends on your bed:

Leave a few millimetres of margin for a skirt or brim; if your bed is borderline, drop one row.

The common magnet size is a 6 × 2 mm neodymium disc, with four per grid cell in the corners of the foot. Magnets make bins hold firmly to a magnet baseplate or a steel surface, which is useful in drawers that get yanked open or on a wall-mounted panel.

1. Pause and insert: add a pause at the layer just above the pocket depth (around 2.6 mm in our magnet bins), press the magnets in, and resume. The layers above trap them permanently.
2. Or glue them afterwards: a small drop of cyanoacrylate (super glue) in each pocket works well.
3. Keep polarity consistent: install every bin magnet with the same face down, and every baseplate magnet with the opposite face up. Then any bin attracts in any cell. Mark one face of your magnet stack with a pen before you start.

Gridfinity parts are designed to print without supports. Typical settings:

• PLA or PETG, 0.2 mm layers, 2–3 walls, 10–15% infill;
• bins upright on their feet, baseplates flat;
• a first layer without heavy elephant’s foot, because the foot profile is what makes bins seat correctly.

If bins sit high or rock in the baseplate, check the first layer first. Our guide to printing multi-part models covers elephant’s foot and clearance in more detail.

1. Measure the inside width, depth and height of the drawer.
2. Divide width and depth by 42 and round down. A 400 × 300 mm drawer fits a 9 × 7 grid (378 × 294 mm).
3. Split the grid into printable baseplate pieces, for example two 4 × 4 plates and smaller strips to fill the rest.
4. Use the leftover gap (22 × 6 mm in the example) for a spacer, or leave it as finger room to lift the baseplate out.
5. Lay out bins on paper or in a spreadsheet before printing, starting with the items you use most.

Because the core dimensions are published, bins and baseplates from different designers mix. Small differences in clearance or lip shape exist, so if one designer’s bins feel tight in another designer’s baseplate, try a test print before committing to a whole drawer. Our pack lists every number it uses (42 mm pitch, 7 mm units, 0.25 mm clearance, and the foot and baseplate profiles) so you can compare.

If you need sizes outside a pack, parametric generators such as the community’s Gridfinity Rebuilt (opens in a new tab) library for OpenSCAD can produce custom bins. AssetLoom’s bins are independently made and Gridfinity-compatible; they are not affiliated with or endorsed by the Gridfinity project.

For more practical desk prints, browse 3D Printing.