Parametric latching box

A parametric box that can either be used as-is or with custom inserts. You can read some of the design considerations that went into this design in this blog post.

There is no STL file attached to this model since it's meant to be the framework for a custom box size. Real examples of this box can be downloaded from my other models:

• Box for Ruthex soldering iron heat-set insert accessories.
• Box for Bambu Lab A1 and A1 Mini nozzles.

Print settings:

• Material: any. I print mine with PLA.
• Layer size: 0.2 mm. Smaller will yield prettier results, but come on, it's a box.

To change the dimensions, open the .f3d file in Autodesk Fusion (it's free for personal use), and go to Modify → Change Parameters. Use the search field to find the parameter you want to change, since there are also a lot of parameters which are derived from the ones you should edit.

IMPORTANT: Fusion often has parametric fragility (the case when editing a parameter breaks the entire model). I recommend “creeping up” on parameter values. For example, if you want to bump the box length from 80 mm to 200 mm, I recommend first going through a couple of intermediate values like 120, 150, etc. and ending up on your target value. “Undo” is your friend.

Note: The default diameter of the hinge and latch pins is 2 mm, but this is of course configurable. I make mine this size because I happen to own a lot of old steel bicycle spokes, and those are usually 2 mm in diameter, and perfect for this use case.

innerLength and innerWidth

The length and width of the inside of the box. Controlling the inside dimensions makes it easier to size your inserts later.

bottomInnerHeight

The height of the inside of the bottom half of the box.

lidInnerHeight

Ditto but for the lid.

innerCornerRadius

The corner radius of the inside of the box. The outer radius is derived from this. When you design an insert, don't forget that the external radius of the insert must match (or be larger than) the inner radius of the box.

wallThickness

The thickness of the walls. The lip between the two halves will be half this thickness.

innerChamfer and outerChamfer

How much the inside and outside of the box is chamfered. Just like the corner radius, when designing an insert, don't forget that the outer chamfer of the insert must match (or be larger than) the inner chamfer of the box.

hingeOuterDiameter

The external diameter of the cylindrical hinge.

hingeSideOffset

How far from the outside edges the two hinges are.

hingeLength

The length of each hinge.

hingePinDiameter

The diameter of the hinge pin.

hingeTolerance

The amount of clearance between the components of the hinge. If you make this zero, the parts might not fit together.

latchLength

The length of the latch pin supports.

latchOuterDiameter

The external diameter of the cylindrical parts of the latch.

latchPinDiameter

Same as hingePinDiameter, but for the latch pin.

latchTolerance

Same as hingeTolerance, but for the parts of the latch mechanism.

latchCenterToCenterLength

The length of the mobile part of the latch. It's measured between the centers of the two circles on the fixed parts.

holeTeardropAngle

The angle of the tip of the teardrop shape of each hole, which helps to avoid overhangs.