How big is the volume gap for a plastic tool box, portable, against steel?

Answer: At a nominal 26 litres, 78 percent against 88 percent, which is 20.3 litres against 22.9.

Why is access twice as fast as plywood?

Answer: The lid stays at 105 degrees unaided and one catch releases it.

How is cost per trip calculated?

Answer: Price divided by trips, plus repairs. 68 yuan over 800 trips is 0.085; add 0.037 for 0.3 repairs a year.

Does a moulded case make sense below 300 units?

Answer: Only with a repeat order; an 80,000 yuan mould over 300 pieces adds 267 yuan each.

Which comparison figure is most often guessed?

Answer: Cycle count, which sets the divisor; an inflated guess makes every option cheap.

Plastic Tool Box, Portable: How It Compares at Equal Volume

Quick answer: Set the same usable volume and the gaps turn into numbers: 78 percent usable volume against 88, six seconds of access against twelve, 0.085 yuan per trip against 0.14. Which gap decides depends on how often the case moves.

Fix the Measuring Basis First
Usable Volume Ratio
Opening Geometry and Access Time
Cost per Trip, Not Purchase Price
Where Each Alternative Still Wins
FAQ

1. Fix the Measuring Basis First

A plastic tool box, portable or fixed, cannot be compared before the basis is fixed. A case of 460 by 330 by 175 mm holds 26.6 litres by outside dimensions, 22 litres inside the walls, and 17 litres once 20 mm foam and two dividers are in place. Folded 1.2 mm steel loses only 0.6 litre to walls; an 18 mm plywood box loses five, so its nominal 26 litres measures 17.5.

The fourth basis is tool sets per trip. A 34-piece kit fits the 22-litre moulded case whole; the plywood box of the same label leaves six pieces out.

2. Usable Volume Ratio

Divide usable litres by nominal litres and the cost of walls, ribs and stacking steps appears at once: 78 percent for the moulded case, 88 for folded steel, 74 for rotomoulding, 69 for 18 mm plywood, all at the same 26-litre label.

Plastic Tool Box, Portable: blue case open about a hundred degrees, grey foam holding a yellow multimeter, black catches and a valve in front

The moulded case loses on wall and rib, but loses carefully. A 2.8 mm wall carries 1.0 mm ribs at 5 mm height, all placed outside, so the cavity stays smooth and 78 percent is the ceiling; move the ribs inward and four points vanish while tools start catching on them. Rotomoulding cannot mould ribs at all, so a uniform 6 mm wall does the work on a body weighing 4.8 kg against 1.9 kg. Steel earns 88 percent with a fold every 300 mm, at the cost of two continuous right angles.

Ten points on a 22-litre case is 2.2 litres, roughly one 300 mm adjustable wrench plus a 25 mm bit box. With a fixed kit, settle that figure before price.

3. Opening Geometry and Access Time

The lid exposes 92 percent of the top face, and a moulded hinge holds at 105 degrees, so one hand steadies it. Timed from catch release to closing, the moulded case takes 6 seconds, steel 12, plywood 15. At 120 cycles a day over 250 working days, the spread reaches 50 to 75 hours a year.

The opening is bounded too: a 400 by 280 mm cavity opens to 372 by 252 mm, a 14 mm flange for catches and seal.

4. Cost per Trip, Not Purchase Price

Price alone ranks the moulded case above plywood and below rotomoulding. Divide 68, 145 and 210 yuan by expected trips, and the order reverses to 0.085, 0.12 and 0.14 yuan.

Plastic Tool Box, Portable: grey case standing open on a workshop bench, six empty foam cutouts, screwdrivers, cables and wrenches in front

Repair and downtime widen the spread. A crack is hot-air welded for 25 yuan in half an hour; steel needs 15 yuan of paint and four hours of drying; plywood gets a new panel. At 180 yuan per stopped hour, one failed catch outweighs the price gap between three cases.

Cost item	Moulded case	Folded steel	Rotomoulded case
Purchase price	68 yuan	145 yuan	210 yuan
Expected trips	800	1200	1500
Cost per trip	0.085 yuan	0.12 yuan	0.14 yuan
Typical repair	25 yuan weld	15 yuan paint	40 yuan rod weld

5. Where Each Alternative Still Wins

Read by row, not by column: each format keeps one job.

Format	Strength	Gap at 22 litres	Right choice when
Moulded case	1.9 kg, 6-second access	78 percent, stacks three loaded	Frequent moves, one-hand carry
Folded steel	88 percent, lid as bench	4.6 kg, 12-second access	Fixed station, hammering
Rotomoulded	Survives a 1.5 m drop	4.8 kg, 74 percent	Vehicle mounting, cold sites
Plywood	32 yuan	Swells, 69 percent	One-way shipment, storage

Tooling never reaches such a table: a steel mould runs 80,000 to 120,000 yuan at a 500-piece minimum, folded steel starts at 50, plywood at 10. Below 300 units, tooling decides the order, not the box.

Conclusion

At equal usable volume the gaps are measurable in litres, seconds and fen: 78 percent against 88, six seconds against twelve, 0.085 against 0.12 yuan per trip. None leads everywhere: load pattern, lid parking and order size each decide a row. With your own figures in those rows, the plastic tool box, portable by design, lands where it belongs.

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.