Cantilever Tote Box

A toy toolbox for people who are masochists about push fits and threading stuff during assembly.

This cantilever box is also unique in that it has a fourth level, independent (non-cascading) opening action, sliding drawers, and an opening that exposes almost the full drawer with little above-level occlusion.

Because of how far it can cantilever outwards, the walls are also designed to act as standing supports.

It’s essentially the result of if a fidget had a baby with a toolbox (a design labradoodle of sorts).

Tools
A M3 Allen Wrench
A motorized M3 hex driver (optional – but HIGHLY recommended)
Parallel pliers (You can use normal pliers, but parallel pliers are recommended)
A poking tool is also recommended.
Snips for post-processing

Printed Parts
Case Wall and Drawer – x2
Drawer – x4
Handle A – x2
Handle B – x2
Handlebar – x2
Handle Nut Sleeve – x4
Hasp A – x2
Hasp B – x2
Latch – x2
Either the tight version or the loose version, based on preference. Tight feels snappier, but loose has fewer mechanical issues.
Link Arms – x24
Technically, they’re called “Arm Links,” but I made a typo in the assembly video, and I’m trying to stay consistent.
Sliding Drawer – x2
Tub – x1

Printing

The files should already be in the correct print orientation. However, there are uploaded image references showing which side should be directly on the print bed.

If you have bed adhesion issues, especially for the handles, consider printing with a brim of ~5mm.

The prints in the screenshots and videos were printed with PLA. PLA or PETG should be used for the latch and hasps. In theory, any material can be used for all other parts.
Extra Parts

This project uses a lot of screws and nuts. Consider what colors of plastic you’re going to use, and then try to decide on a complementary screw finish (usually between shiny stainless steel or black-finished screws).

M3 Hex Nuts – x8
M3-10 Socket Hex Screws – x4
M3-12 Socket Hex Screws – x4
M3-14 Socket Hex Screws – x4
M3-25 Socket Hex Screws – x4

Since the screws are also used as hinges, a method for thread locking is needed to mitigate the screws loosening. There are two options for thread-locking: nylon locknuts or the application of a thread locker.

If using locknuts:

M3 Nylon Hex Locknuts (w\o flange) – x52
M3-10 Socket Hex Screws – x48

If using a thread locker

Threadlocker
Loctite is the recommended brand name. Red, purple, or blue, you’re choice.
M3 Hex Nuts – x52 (in addition to the previous 8)
M3-8 Socket Hex Screws – x48

For the large amounts of screws and nuts needed, I recommend avoiding buying them as assortment packs. Buy in small bulk, either from a bulk Amazon vendor or eBay.

Assembly

For more details, see the YouTube Assembly Video. However, reference this project page for the accurate BOM.

Prep:
For the Nut Sleeves, cut any loose overhang.
For the Handles, trim any loose overhang on the connection bar.
Inside the Handlebar, remove any filament strings and debris inside the body.
If anything is printed with brims, trim any brim that needs to be cleaned up.

Handlebars
Push fit the M3 nuts into the Nut Sleeves.
Push a Handle into the Case Wall.
These parts should be indexed so that they cannot be put in the wrong direction.
Place a Nut Sleeve on the inside of the Case Wall, against the inserted Handle. Mind that it fits with the correct orientation.

Thread a M3-14 screw through the pieces.
Fit the Handle into the Handlebar. Make sure the side of the handle with the lower lip faces the outside of the box.
Hold the assembly upside down and insert an M3 nut into the body of the Handlebar so that it fits in the seat.
This is where the poker comes in handy.

Thread an M3-10 through them.
Repeat attaching the Handles through the Case Walls, and the Handlebars to the Handles, until all Handles and Handlebars are used up.

Sliding Drawers
Put sliding drawers into their cavity in the Case Wall.

Tub
Place a (lock) nut on the open seating at the bottom of the Tub.
Place a Hasp on the other side (on the outside of the box) of that seat’s bore.
Make sure you’re using a Hasp with the correct orientation and that the head seating faces the outside of the box.
Thread them together with an M3-12 screw.
This will be an M3-12 screw regardless of if you decide to use a thread locker or a lock nut.

Tighten the screw so that the hasp rotates easily when pressure is applied with fingers but does not rotate freely if not being actively pushed.
Repeat for all hasps.

Cantilever Drawers
For simplicity in this section, all screws will be referred to as an M3-10 screw, and all nuts will be referred to as lock nuts. But if you’re using a thread locker, replace it with M3-8 screws, and use regular nuts that have been treated with thread locker.

If using a thread locker, wait until nuts have been push-fitted, and apply from the outside of the box.

For all the nuts seats on top of the Tub, use the pliers to push-fit M3 nuts into all eight sockets.
For all the nut seats in all the Drawers, push-fit M3 nuts into all the sockets.
For all the nut seats in the Case Walls, push-fit M3 nuts into all the sockets.
To make it easier, push-fit the sockets farther back before doing the ones up front.

Stack the drawers on top of the Tub and place the Case Walls on the outside of that subassembly to mimic how the final box will be structured.
Align a link arm to match with the bores so that, from a bottom bore, it goes up and towards the center.
See the photo of the assembled sides for more information.
Make sure the screw head seats face outwards.
If using a thread locker, apply the thread locker to the outer bore of the box.

Use 2 M3-10 screws to attach the Link Arm to the two different layers of the box.
Do not over-tighten, but don’t worry about screw tightness for now.

Repeat for all Link Arms.
Carefully test the opening and closing of the box. If it does not open easily, do not apply extra force and stop testing.
By hand, tighten or loosen all Link Arm screws so that the Link Arms have minimal play with the screws but also that the box opens easily.

Latch
Thread 2 M3-25 screws through the latch hinging mechanisms on one of the Case Walls.
Align the two latch hinges with the hinging mechanism on the other Case Wall.
Make sure the latch isn’t placed upside down.
Carefully bore 2 M3-25 screws through them.
Do not overtighten, or else it could pinch in the hinges.
Test the latch swivels correctly.

Thread Locker Cureing
If using a thread locker, let it sit for 24 hours as per its instructions for curing.

Notes and Caveats
The box is somewhat unintuitive because it has several things that need to be locked and unlocked to open/close (2 latches and 4 hasps). If you let other people handle the box, make sure they realize this and don’t blindly open it with too much force before checking first.

Because the handles are aligned upwards but don’t swivel, they should NOT be pulled horizontally to open the box. Instead, HOLD THE BOX BY THE SIDES AND PULL HORIZONTALLY. The fix to this is probably to make the handles swivel, but that will need to be done in a future design.

Corners that form from being printed on the first layer against the print bed can be sharp.

Do not apply rolling/twisting force on the box. Because the links are placed so close together, they don’t have much mechanical strength against twisting.

Credits:

Reavenk