Half past seven, service van parked on a street in Stuttgart, and the case opens flat on the passenger seat. Every tool has to be visible in about two seconds, because if anything is buried the technician leaves it behind and notices at the second job of the day. That is the test every EVA tool case either passes or fails, and it has very little to do with how the shell photographs.
One trade, one layout
- HVAC and plumbing: heavy steel, wet ground, so the shell gets a Shore C 65 to 70 wall, a wide base that can be set down in mud and hosed off, and drain grommets if the client asks for them.
- Metrology and calibration: dial gauges, soft jaws, torque wrenches with certificates. Insert foam at around 30 kg/m3 with close to zero clearance, plus a clear label window so the next calibration date is readable without unpacking.
- Site electrical: dozens of small consumables. A two-layer stack with a lift-out tray beats one deep cavity, because nobody wants to dig through terminals to reach a connector.
The insert does more work than the shell
A sheet of PE foam at 15 to 25 kg/m3 looks fine in a sample photo and then flattens out after six months under a 1.5 kg impact wrench, which is why most tool inserts get specified at 30 kg/m3 or above. Cavity walls are normally left 5 to 10 mm thick, with 2 to 3 mm of clearance around each part and a finger scoop cut at roughly a 20 mm radius so a gloved hand can lift the piece out. All of that gets settled on the customization workflow before a tool is cut, since changing a foam layout after the shell exists means new dies and another sample round.
Weight, grip and what breaks first
Empty weight decides whether a case rides into the job or stays in the van. Most 16-inch tool cases are designed to land somewhere between 1.2 and 1.8 kg empty for single-handed carry, which means trading shell thickness against strap width. Ask what fails in the field and the answer is nearly the same every time: the zipper first, then the handle attachment, then a torn cavity wall. Box stitching under load-bearing handles and a zipper garage at each end of the track handle the first two, and both cost a few cents rather than a few dollars when they are decided early.
Shipment checks are separate from design checks. Replacement kits sent straight to customer sites by parcel get qualified to ISTA 2A, meaning vibration plus drops in whatever carton the carrier will actually use rather than an idealised one, and material declarations cover RoHS, REACH and CA Prop 65 for European and Californian importers. The order leaving next week is 40 cases of a torque wrench kit for a wind-turbine maintenance crew, each one packed with its own calibration sheet tucked into the lid pocket.