Which test comes first when choosing a tool case?

Answer: Usable internal volume, because it fixes the shell and the mould, and a mould change costs four to six weeks.

How far off is nominal volume from what fits?

Answer: A 45 litre shell measures 33 to 36 litres inside. Multiply tool volume by 1.3 before comparing.

How much weight can the handle take?

Answer: A case loaded to 18 kg needs a 45 kg static rating, 2.5 times the load. Beyond that, use a wheeled case.

Does a tool case need IP67?

Answer: IP65 covers most sites. Choose IP67 only where the case may sit in 1 m of water for 30 minutes.

Injection moulded or rotomoulded?

Answer: Injection at 2.8 to 3.2 mm gives lighter weight and tighter slots; rotomoulding at 4 to 6 mm absorbs impact better.

How to Choose a Tool Case: Five Tests That Decide It

Quick answer: Work in one order: usable internal volume, slots per 10 litres, handle load at full weight, latches and ingress rating, then wall thickness and stacking. Clearing all five before the mould opens costs less than re-cutting foam.

Five Tests That Decide a Tool Case
Test One and Two: Usable Volume and Slot Density
Test Three: Loaded Weight and Handle Load
Test Four: Latches and Ingress Rating
Test Five: Resin, Wall and Stacking
FAQ

1. Five Tests That Decide a Tool Case

A tool case spec sheet runs to a dozen lines, but five decide the outcome: usable volume, slot count, handle load, latch and seal, and wall against stacking. They are ordered: nothing downstream settles until volume and slots fix the shell.

Cost rises along that order: re-cutting foam takes an afternoon, a 600 mm mould four to six weeks. Fix the outside first and corrections stay cheap.

Test	Pass value	Failure looks like
Usable volume	72%–80% of nominal	Lid forced down on the gasket
Slot density	6–9 per 10 litres	Tools strike each other
Handle load	2.5× loaded weight	Cracks at the handle root
Latch and seal	Two latches, IP65	Water entry, latches popping
Wall and stacking	2.8–3.2 mm, three tiers	Sidewalls bow, base collapses

2. Test One and Two: Usable Volume and Slot Density

Nominal volume is measured outside, usable volume inside, with walls, ribs and the lid recess in between. A 45 litre shell returns 33 to 36 litres once 3 mm walls and a 12 mm recess are subtracted, so tools sized on the nominal figure overfill by a fifth.

Tool Case: a blue hard-shell case standing closed at an angle, ribbed lid, one metal latch, moulded handle and a round pressure valve

Slots run 6 to 9 per 10 litres: long tools across one position, sockets in blocks of 8 to 12, measuring tools in their own bay with 5 mm clearance. Keep fill at 75 percent for finger room. Doubling slots from 12 to 24 in the same 35 litre shell cuts clear width from 60 mm to 32 mm.

Volume	Usable cavity	Slots	Suits
18 L	13–15 L	10–14	Route inspection
35 L	26–29 L	18–24	Machine repair
60 L	44–48 L	26–32	Bench stock
90 L wheeled	66–72 L	32–40	Field support

3. Test Three: Loaded Weight and Handle Load

The handle fails first: it carries everything plus the dynamic peak. Design to 2.5 times loaded weight, so 18 kg loaded needs a 45 kg static rating, and a 1.2 m drop on six faces must not pull the handle out.

Keep one-person carry under 18 kg. With a 3.5 kg shell that leaves 14.5 kg of tools; beyond it, use a wheeled tool case or a two-person lift with grips at least 300 mm apart. The grip wants 28 mm of section and 25 mm clearance for a gloved hand.

4. Test Four: Latches and Ingress Rating

Two latches serve a 500 mm case, spans under 250 mm; three above 600 mm. One metal draw latch holds about 30 kg, so a pair covers 60 kg against a 45 kg load.

Tool Case: a black hard-shell case open flat, flat foam in the lid, die-cut cavities for wrenches in the base, two latches and a handle

IP65 stops jets and suits most workshops. IP67 means 30 minutes at 1 m and stiffens the opening, so past 80 N fit a relief valve. Hardware should show no red rust after 48 hours of salt spray; a flat gasket lifts out without the hinge.

5. Test Five: Resin, Wall and Stacking

Injection shells run 2.8 to 3.2 mm with ribs every 80 to 120 mm; rotomoulded shells run 4 to 6 mm and weigh a third more. Cold work needs a −20 °C drop test: 5 kg from 1 m without a split corner.

Stack three tiers at 120 kg on the bottom case, never on the handle. At four tiers sidewalls bow 2 to 3 mm and lids stop closing.

Conflict	Hold	Trade
Field repair, constant moves	Seal and handle	Slot density
Fixed bench, frequent access	Slots, opening force	Ingress rating
Warehouse cycling	Stacking and wall	Handle load

Conclusion

The five tests form one line: volume and slots fix the shell, handle load decides how it travels, latches and seals answer water and dust, resin and stacking decide how long it lasts in a store. A tool case taken through all five still closes cleanly after three years.

This article discusses only the container (case body) side of specifications and design intent, and does not cover any handling, loading or use of the contents.