TL;DR: A California central kitchen rejected an entire batch of custom-depth stainless steel sink stations after a third-party inspection measured three units at 753–755mm, exceeding the contracted 750mm ±3mm tolerance. The parts were built correctly. The inspector had measured total depth including the backsplash, not the working surface depth specified on the drawing. Once the measurement baseline was corrected, all units passed.
The Rejection
Last May, we delivered a batch of custom-depth stainless steel sink stations to a central kitchen in California. The contract specified a working surface depth of 750mm, with tolerance governed by ANSI/BIFMA standards — ±3mm. After delivery, the client’s third-party acceptance team used a laser distance meter to spot-check six units. Three measured between 753mm and 755mm, exceeding the upper tolerance limit by up to 2mm. The inspection team flagged these as “out of tolerance” in their report. The client rejected the full batch and requested we cover return shipping and rework costs.
Checking Our Own Records First
We pulled the CAD drawings and the CNC bending machine’s production logs for this batch. The logs showed the bending parameters matched the drawing exactly — in theory, finished dimensions should have fallen within tolerance. So the discrepancy likely wasn’t in fabrication. It was more likely in how the measurement was taken.
We asked the client to remove one of the disputed units from its packaging and re-measure it on a calibrated flat surface, this time with us present. That’s when the discrepancy became clear: the inspection team had measured total depth, from the front edge of the work surface to the outermost edge of the rear backsplash. But the 750mm dimension on the drawing referred specifically to the effective working surface depth — not including the backsplash.
The backsplash is a stainless steel panel welded to the rear edge of the worktop, 150mm tall, 1.5mm thick, with a bend radius at the base. That bend and panel thickness together add roughly 3.5mm of physical depth beyond the working surface. In other words, once you subtract the backsplash structure and bending allowance from the measured 753–755mm total depth, the actual effective working surface depth falls squarely within 750mm ±1mm.
Resolving It With a Side-by-Side Comparison
We built a technical comparison table showing the drawing’s baseline annotation against the on-site disassembled measurement. The client’s inspection team reviewed it and acknowledged they had taken the outer edge reading without confirming whether the drawing’s 750mm referred to total depth or working surface depth. The inspection finding was corrected to “within tolerance,” and the shipment was accepted as delivered.
Key Takeaway
This wasn’t a manufacturing deviation — it was a measurement baseline mismatch. For more on work table dimensions and configuration, or sink sizing and specification, check out our buying guides. On any custom stainless steel fabrication drawing, dimensions can reference different reference points (working surface vs. overall footprint, inside edge vs. outside edge), and a backsplash, flange, or bend radius can easily account for a few millimeters of apparent “excess.” Before a batch gets rejected over a tolerance finding, it’s worth confirming exactly which reference point the drawing’s dimension describes — and having the disputed part re-measured against that specific baseline, not just re-measured in general.
For buyers reviewing incoming custom stainless steel equipment: always ask your fabricator to confirm which surface or edge a dimension is measured from before treating a variance as a defect.
Questions about tolerance standards or measurement baselines on a custom fabrication project? Contact our engineering team for a technical consultation.
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Frequently Asked Questions
What tolerance can I expect on custom stainless steel fabrication?
We state the tolerance in writing on the order confirmation, and every unit is checked against it before packing. This case shows why agreeing on the measurement baseline up front matters as much as the tolerance number itself.
What happens if a unit does not match the agreed dimensions?
You document it with photos and measurements, we check our production records, and we resolve it with evidence — replacement, rework, or correction. The comparison method in this case is how the disagreement was settled without escalation.
Can you match dimensions to existing equipment on site?
Yes — send us field measurements or the adjacent unit’s drawings, and we fabricate to those numbers. Custom builds run the same 3–5 day production as standard sizes: custom fabrication.