----- Date:

Case for Eyeglasses, with Belt Clip

Mark's Enclosure Helper - Eyeglass Belt Case #

Our daughter, Esme, got her first pair of eye glasses recently. Being an American pre-teen her normal wardrobe has no place for her to keep them safely as she goes about her daily activities. She needs a case which that can attach to her clothing or back pack, that's tough enough to survive the hectic and physical life she leads.


This is after school the first day she's used this outside. It survived!


We've designed this box to be slightly difficult to open; the hinges are offset slightly which adds extra "spring" to the top when its closed. The hope is the box will open only by intent and effort and accidental bumps and scrapes will not knock the lid loose.

opening box pic

Squeezing the front and back faces of the box together as shown should result in the top popping up, possibly a small amount of force of the clasp will be needed. Ours just pop open.


You will need to line the box interior with something to keep the lenses of eye glasses from getting scratched up by the plastic. We sized the box to fit a pair of glasses in the cheap foam / leatherette 'reading glasses' cases we found to be ubiquitously available. Folded a little bit and with the top trimmed it provides padding and protection, and enough spare space for a pencil.

case glasses insertion

glasses insertion

(This box suffered a layer shift during printing, but is still strong enough and pretty enough for what we needed).

We've provided STL files of a belt clip version (open on one side) and a belt loop (closed on both sides of the loop). An adult size belt will be thicker than the 5mm opening this model has. That size is good for the camera bag strap we need it for.



Printing #

We've printed these in PLA with a 0.5mm nozzle, with support material and brims.

We suggest very high infill and/or soilid infill especially for the body of the hinge and belt clip areas.

We are using Slic3rPE, and the solid infill threshold area setting in Print Settings > Infill is the variable that might cause the infill to switch to solid in that part of the object if you have trouble tracking that down. Other slicers certainly have a similar value but we can't guide you about them.

See the Box Assembly instructions for details of how to use two zip ties as hinge pins. an M3x40mm screw and nut would also work (and have less play in the action) but those tend to be expensive and hard to source.


Design #

The hinge_standoff value makes the top more firm when closed, by changing the geometry of rotation of the lid when it opens. "The tooth drags the catch harder" is the best explaination we can offer at the moment. This also gives the top the "pop" spring when it opens.

The catch_thick at 3mm is Very thick for use, we hope its thick enough to survive hard usage. Smaller fingers and gentler circumstances would almost certainly find the catch easier to use with a catch_thick of down to 1.5mm or so, and you might even want to turn the wall_thick back down a hair.

The hinge_basepoint is set fairly arbitraily at 100mm, move it freely for a different balance point, the box top hinges will need room to fit when its open but otherwise the clip could run right up to the top.