A Portable Tool Box weighs 2.6 kg more than a bag, so why carry it?

Answer: Grip and swing decide effort: a padded 28 mm handle peaks at 195 N over 200 m, a bare 22 mm strap with 40 mm of swing at 260 N.

Steel is stronger, so why does the steel chest fail a drop?

Answer: The fold fails, not the sheet: an 8 mm dent lifts the rim 2.5 mm and the seal is gone, whereas a moulded shell recovers.

The trolley accesses in 3.1 s, so why not use it everywhere?

Answer: That assumes it is at the bench. At 78 kg and 690 mm wide it cannot climb scaffold, and a round trip costs six minutes.

Can an unlatched bin do the job?

Answer: For short dry indoor moves. It leaks when inverted, spills when tipped, and indexes 230 against 118.

Which numbers settle the choice?

Answer: Daily moves, one-way distance, dust and water. Over ten moves a day and 30 m points to a rigid case.

Portable Tool Box vs Alternatives: Where the Gap Shows

Quick answer: At 21 L and 8 kg of load, a Portable Tool Box carries 0.20 kg of shell per litre, a fabric bag 0.076, a steel chest 0.38, a drawer trolley 0.65. Lighter is not easier: after 200 m the bag peaks 65 N higher at the grip.

How a Portable Tool Box Compares With Four Alternatives
Where the Protection Gap Shows Up
Weight to Volume for the Same Load
Carrying and Access Speed, Measured
Life Cycle Cost per Year
FAQ

1. How a Portable Tool Box Compares With Four Alternatives

Set the terms first: 21 L usable volume, 8 kg load, 5 to 35 °C, 30 open-close cycles a day. The alternatives are a 1680D nylon bag, a steel chest in 0.8 mm sheet, a five-drawer trolley and an unlatched bin.

The case is 460 × 350 × 180 mm outside, 2.6 mm wall, 4.2 kg empty, or 0.20 kg/L. Light and heavy here mean that ratio, not a scale reading.

Option	Outside, mm	Empty	Per litre
Portable Tool Box	460×350×180	4.2 kg	0.20 kg/L
Fabric bag	480×300×280	1.6 kg	0.076 kg/L
Steel chest	460×220×200	6.8 kg	0.38 kg/L
Drawer trolley	690×470×950	78 kg	0.65 kg/L
Unlatched bin	500×350×300	3.8 kg	0.10 kg/L

2. Where the Protection Gap Shows Up

Ten corner drops from one metre separate the field. The 2.6 mm wall and R10 corners hold the lid gap inside 0.4 mm; the steel chest dents 8 mm and lifts its rim 2.5 mm; the bag's zip bursts on the third drop.

Portable Tool Box: blue case on a wooden bench, two same-colour latches on the front, trays of black bolts and silver screws behind, workshop window

Sealing is a path, not a material. A 3.5 mm gasket squeezed to 2.3 mm, 34%, balances rebound against latch force. Folded steel leaves a 0.3 mm hinge channel, enough for fine dust to run the length.

Item	Portable Tool Box	Fabric bag	Steel chest	Storage bin
Lid gap, ten drops	0.4 mm	zip burst	2.5 mm	shifted 6 mm
Dust	34% squeeze	woven pores	open hinge	no seal
Water	short rain	none	seam seep	leaks inverted

3. Weight to Volume for the Same Load

On ratio the bag wins at 0.076 kg/L, 38% of the case. Loaded, the bag totals 9.6 kg with 17% in the shell, the case 12.2 kg with 34%; the 2.6 kg difference is frame and gasket.

Over 200 m a 28 mm handle with R6 edges peaks at 195 N; a 22 mm unpadded strap, swinging each step, peaks at 260 N, one hand change at the 100 m mark.

4. Carrying and Access Speed, Measured

Access is a single-part round trip, thirty runs, median. The case takes 4.5 s, its lid stopping at 105 degrees so a tray lifts out; the bag 8.2 s, the steel chest 6.4 s, the bin 5.6 s, the trolley 3.1 s parked.

Portable Tool Box: five grey cases on a white table, trays of sockets and wrenches, two compartment boxes of screws, one empty case behind

Carrying is 30 m out and three 1.8 m scaffold levels. The case takes 3 min 10 s in one hand through a 700 mm gap; the bag 3 min 40 s with two hand changes; the trolley cannot take stairs and needs a goods lift.

5. Life Cycle Cost per Year

Five years at 240 days and 30 cycles is 36,000 events. A 3 mm pin in a PA66 bush reaches 0.35 mm of play at 50,000 cycles; the bag's zip skips teeth at 12,000, the steel chest cracks at its welds near 18,000.

Option	Cycles	Failure point	Index
Portable Tool Box	50,000	gasket, latches	118
Fabric bag	12,000	zip, stitching	265
Steel chest	18,000	welds, rust	190
Drawer trolley	40,000	slides, castors	145
Unlatched bin	20,000	warped lid	230

The index is five-year spend against a list price of 100. Travel with dust and rain points to the 0.20 kg/L shell, bench work to drawers.

Conclusion

No alternative loses on every count; each bought one property with another: the bag lightness, the chest stiffness, the trolley search speed, the bin a low price, while a Portable Tool Box buys protection and transit speed together.

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.