A long time ago, I bought an Office Depot Mini Milk Crate (at a brick and mortar store). I recently stumbled upon it in a drawer I rarely open, and after all these years, I appreciated how handy it is and decided to buy more. However, I then discovered they're out of production, and I can only imagine for how long - according to the WayBack Machine, at least for a decade.

So I decided to make a replica. It had some features that I wanted to keep, but that aren't viable with FDM printing, mainly dealing with overhangs, but also surface finish. These issues were solvable if all five sides were designed to be printed flat on the bed, and then assembled afterwards.

Also, the original mini-crate is ever-so-slightly rectangular. I have made the design choice not to be a gaslighter, and the X/Y shape of this replica box is a square.

For demo and assembly, see video at https://youtu.be/FF3ImFdHRiA

Printing

There are two versions of the box that can be made, one with the indexing pegs, and ones without. The ones without the pegs will have the prefix "NoIdx_" in their filename.

For each box, print:

• Crate_Floor.st
  • x1
• Crate_WallA.stl or NoIdxCrate_WallA.stl
  • x2
• Crate_WallB.stl or NoIdxCrate_WallB.stl
  • x2

You must print 2 of each type, and A specifically locks into B, and vice versa. Meaning you cannot print 3 or 4 of a single wall type - and it will not lock into itself (WallA doesn't interlock into WallA, and the same for WallB).

All *.stl files should already be oriented the correct way, so that the proper side is lying on the bed.

Tested and worked with both PLA and PETG filament. Filament should not be brittle, and the prints should be of good print quality. If the prints are brittle, then the walls can tear during the assembly process. From testing, the PrusaXL consistently printed working parts, but parts printed from the PrusaMini were inconsistent.

Print Settings

Usually, I don't include settings because I don't consider print settings too important; however, there are several functional expectations for this print to ensure proper assembly. So these exact values may not be necessary, but are probably relevant to share.

• Layer height: 0.2mm
• Perimeter: 2
• Infill: 15%
• Fill pattern: Grid

Tested Filaments

In the project gallery,

• The silk gold and blue crates are Amazon Basic and print well.
• The red ones are OVERTURE PETG and print well.
• The transparent orange is SUNLU PLA printed on the PrusaMin, and had precision issues with the indexing features.
• ZIRO Starry Sky filament cracked in multiple places during assembly.

Tools

• A hammer
• Pliers

I recommend using a rubber mallet and wrapping the plier clamps in a couple or more layers of soft tape (such as duct tape). This is to prevent leaving dents in the plastic during assembly.

Also, only assemble on a surface you don't mind hammering on.

Assembly

See the project video for more details.

There are two terms, that can sometimes be used synonymously, which will be used to mean specific things in these instructions:

• Box joints: The joints connecting the sides of the walls together.
• Finger joints: The joints that connect the floor to the bottom of the walls.

1. Take two walls of the same type (two WallA or two WallB) and hammer them into the floor piece with the floor's finger joints.
   • The walls' flat side should face inwards ( to the box when the box is fully assembled).
   • The face of the walls that have more complex depth details should face outwards
   • The part of the floor that has more complex depth details should face outwards
   • Lightly, and repeatedly hammer the finger joints at various places along the joint line. You should hear a creaking sound every time the plastic slips into the joint a bit more. Keep tapping until the creaking sound stops.
2. Hammer the 3rd wall into place, into the floor finger joints.
   • Hammer the bottom box joint along the wall edges into place.
   • This may knock out the previous walls from the floor joint. Rehammer them back in if needed.
   • DO NOT try to hammer into place the other box joints above the floor.
3. With the pliers, starting from the floor box joint that should have been connected in the previous step, connect the other box joints. Do so by progressively moving upwards, almost like pulling up a zipper.
   • It helps to make sure the box joints are aligned before clamping them into place.
   • Usually, but not always, you'll hear a snapping sound when the box joint is secure.
   • Be careful, for bad prints, this is the step where parts can easily crack.
4. Add the 4th wall by connecting its finger joints to the floor piece.
5. Secure the last 2 box joint edges.
6. Recheck clamping every box joint along the 4 edges. It's easy to miss box joints, plus sometimes the joints can slightly slip out while assembling other parts.
7. Recheck hammering the floor finger-joints to the wall. Retap all joint holes, ensuring there's no additional creaking sound.
8. Final visual spot check for the joints, along the wall edges, and for the floor finger joints. The floor joints can also be checked for how much light slips through the bottom. No light should slip through - or if it does, it should be a thin, consistent sliver across the entire wall-floor connection.

Warning/Caveats

• Be aware of fingers when hammering.
• If handled roughly, box joints may tear. Although I haven't had this happen yet, even with crates filled with drives and metal tools. But this is an obvious possibility.
  • When possible, pick up crates with two hands or from the bottom.
• Crates should not be considered disassemblable. Once assembled, completely tearing apart the joints should be avoided, as it can cause fatigue and damage them.

Gridfinity Insert

When placing thin-and-long shaped tools in, you can pack them in an organized way if you can store them standing vertically. Coincidentally, the size copied from the Office Depot box is slightly larger than a standard Gridfinity 3x3 grid.

For the baseplate:

• Go to PerplexingLabs' Gridfinity generator.
• Go to the Baseplate tab (if not already on it)
• Use the default parameters (they will be listed below if you want to double-check they didn't change over time).
• Press the "Render" button
• Press the "Download" button

Settings

• Grid base size: 42
• Grid rows: 3
• Grid columns : 3
• Minimum base length: 0
• Minimum base width: 0
• Style: Skeletonized
• Bin screw hole style: None
• Magnet pockets: On
• Magnet radius: 3.25
• Magnet crush ribs: Off
• Magnet Hole Chamfer: Off

You can also get rid of the magnet sockets, but I was too lazy to change any of the default settings since I didn't need to.

For the bins:

• Go to the PerplexingLabs' Gridfinity generator
• Select the "Basic Bin" tab.
• Select your preferred Grid rows and Grid columns settings.
• Select your preferred Height settings. Something between 6 and 12 works well. Keep in mind that bins of the same dimensions are vertically stackable.
• Set Finger scoop to 0.
• Set Label tab to None.
• Press the "Render" button.
• Press the "Download" button.

Settings:

• Grid rows: [1,3]
• Grid columns: [1,3]
• Height: [6,12]
• Grid base size: 42
• Stacking lip: _(ツ)_/
• Wall thickness: 0.95
• Magnet style: Gridfinity Refined
• Magnets on corners only: Off
• Screw holes: Off
• Magnet radius: 2.93
• Magnet depth: 2.1
• Thumbscrew: Off
• Bin Style: Standard
• Sub-bin rows: 1
• Sub-bin columns: 1
• Finger scoop: 0
• Label tab: None

Source File

Blender source file included. It contains a Python script that adds tooling for turning the indexing pegs on and off. Do not run the Python script (or any 3rd party Python scripts) if you cannot read them to verify their safety, and if you do not trust the source of the script.