What is the minimum set of items for a Metal Tool Chest acceptance standard?

Answer: One per stage: plate tolerance, weld pull-out, coating with salt spray, drawer load.

Is plus or minus 0.05 mm on plate too tight for a mill?

Answer: Cold rolled sheet already holds 0.03 mm; the target is a 0.9 mm coil sold as 1.0 mm, so judge on the thinnest reading.

Where does the 1.2 kN pull-out figure come from?

Answer: A 45 kg drawer on four spots, times a 1.25 lifting factor, needs 0.9 kN per spot; 1.2 kN keeps a 30 percent margin.

Should salt spray be 240 or 480 hours?

Answer: Follow where the chest sits: 240 hours indoor, 480 hours coastal and at sea.

How is the 0.3 percent interchange rate sampled?

Answer: Fifty keys against fifty locks, 2,500 attempts, seven opens allowed. Below 30 keys one open already exceeds 3 percent.

Metal Tool Chest Acceptance: Test Items and Pass Limits

Quick answer: A Metal Tool Chest is accepted in four stages: sheet and hardware, bend angle and weld spots, coating and salt spray, then drawer load and runner life. Hold plate to plus or minus 0.05 mm, weld pitch at 40 to 60 mm with 1.2 kN pull-out and runners at 50,000 cycles.

Incoming Inspection Items and Limits for Metal Tool Chests
Thickness and Formed Part Tolerances
Weld Pitch and Pull-Out Strength
Coating Thickness and Salt Spray Sampling
Drawer Load, Runner Life and Key Interchange
FAQ

1. Incoming Inspection Items and Limits for Metal Tool Chests

Incoming inspection covers sheet and hardware, not a finished body: once a Metal Tool Chest is bent, the bend zone stretches, so gauge is read on flat areas.

Sheet is sampled by lot: one heat, three coupons, five readings each at least 50 mm from an edge. Nominal 1.0 mm cold rolled passes from 0.95 to 1.05 mm, or plus or minus 0.05 mm. A 0.94 mm lot goes back, because runner holes shift with gauge.

Hardware is judged apart: runners, locks, castors and handles are sampled to GB/T 2828.1 level II, majors counted separately from minors.

Lot size	Sample	Accept, major	Accept, minor
151 to 280	32	1	2
281 to 500	50	1	3
501 to 1200	80	2	5

2. Thickness and Formed Part Tolerances

On a Metal Tool Chest, a formed part is judged on bend angle, inside radius and hole-to-fold distance. Angle holds within plus or minus 0.5 degrees, read at both ends. Radius floors at 1.5 times gauge: 1.2 mm on 0.8 mm sheet, 1.5 mm on 1.0 mm, 1.8 mm on 1.2 mm. Hole-to-fold holds within 0.3 mm, or runners sit crooked.

Bodies are judged for squareness: empty on a surface plate, diagonals must agree within 2 mm, with the base pan gap under 1.0 mm.

3. Weld Pitch and Pull-Out Strength

Bodies are spot welded with folded seams, so spots carry the strength verdict. Pitch runs 40 to 60 mm on loaded edges such as base-to-side joints, and 80 to 100 mm on partitions. Past 60 mm, the base pan bulges on the first full lift.

Pull testing is destructive and sampled: two bodies per lot at 10 mm per minute, 1.2 kN minimum. Batches under 1.0 kN trace to low current or oil. Tips are dressed every 800 spots and replaced at 8 mm.

Item	Limit	Gauge
Pitch, loaded edge	40 to 60 mm	steel rule
Pitch, inner edge	80 to 100 mm	steel rule
Pull-out force	1.2 kN minimum	pull tester
Indentation	0.15 mm max	depth gauge

4. Coating Thickness and Salt Spray Sampling

Coating limits need defined reading points. Powder coat on a Metal Tool Chest runs 60 to 80 micrometres, five readings per face, one inside 10 mm of a bend. That bend reading sits 20 percent low from the Faraday cage effect and is logged, not judged; the verdict uses four flat readings and fails below 50 micrometres.

Salt spray follows service: 240 hours indoor with rust under 5 percent, 480 hours for coastal and vehicle use with scribe creep under 2 mm. Hot dip galvanising needs 60 grams of zinc per square metre, about 42 micrometres.

Adhesion uses a 1 mm cross hatch, grade 1 passing; galvanised-then-powdered parts need two tests.

5. Drawer Load, Runner Life and Key Interchange

Drawer load on a Metal Tool Chest is judged on load, dwell and set: 35 kg distributed, 24 hours, one hour of rest, then 1 mm at the base centre. Light chests load 25 kg, heavy ones 45 kg.

Runner life counts strokes: 50,000 cycles over 90 percent of travel at 10 per minute, after which side play may grow 0.3 mm. A stumble near 30,000 cycles means grease pushed out or a deformed cage.

Locks are judged on interchange: 50 keys against 50 locks, 2,500 attempts, 7 opens allowed. Cam locks need 12 mm of bolt throw; castors roll 8 km with 1 mm of tread wear.

Item	Limit
Drawer static load	set 1 mm max at 45 kg
Runner life	play growth 0.3 mm
Key interchange	7 opens in 2,500

Conclusion

Acceptance is not a list of features but a set of conditions, each with a reading point, a sample size and a limit. Gauge is judged on the extreme, formed parts on angle, coating on flat-area means, finished units on set, runner play and interchange. Put them in one document and inspection stops being a look at a sample, which keeps a Metal Tool Chest consistent by lot.

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.