When a QC report lands in your inbox, it speaks a dialect: seam skips, twisted heels, lot shading, oil marks. Buyers who cannot read it negotiate in the dark — and buyers who can read it turn inspection days into leverage. This glossary covers the twelve defect terms that actually matter in sock programs, each with what it is, which process step it comes from, and what you do when you find it. The vocabulary is the inspection discipline applied word by word.
Quick answer: sock defects cluster by process. Knitting produces holes, missing courses, and needle lines; toe-closing produces seam skips and rough seams; dyeing produces lot-to-lot shading and panel color differences; boarding and finishing produce size and appearance faults; packing produces mixed sizes and mislabels. A working QC conversation sorts every finding into critical (safety or unsellable), major (visible, functional), and minor (cosmetic) — the standard severity logic of acceptance sampling — and agrees on the split before the container ships, not after. Twelve terms below; learn them and inspection reports become maps instead of noise.
The Twelve Terms
1. Seam skip (skipped stitch in toe closure). A stitch missed in the closing operation — a small gap in the toe seam. From the toe-closing step; the fix is machine setting and operator attention. Buyer check: run a finger inside the toe; skips catch. Severity: major at any size a customer would feel (closure hierarchy).
2. Twisted heel. The heel pocket rotated out of alignment — the sock's heel does not sit under your heel. From linking or boarding misalignment. Visible when the sock is flattened: the leg and foot axes disagree. Major: it walks the sock off the foot.
3. Hole / needle break. A void in the knit where a needle broke and the machine kept running. Knitting step; good mills repair or cull, never ship. Critical at any size — holes grow in the wash.
4. Missing course (dropped course). A row of knitting absent — a horizontal gap or run. Knitting step, yarn-feed or machine issue. Critical to major depending on size and location; catch by holding the sock to light.
5. Lot-to-lot shading. Two production lots of the "same" color that do not match each other. Dyeing step; the color consistency program exists to prevent it. Buyer check: compare bags across cartons under the same light. Major when the program sells color.
6. Panel color difference. Different panels of the same sock (leg versus foot, stripe versus ground) off-shade — dye uptake variance across yarn or machine feeds. Dyeing/knitting interplay; visible in flat inspection. Major for multicolor programs.
7. Oil stain. Machine lubricant marking the knit — grey or yellowish spots, often near the cuff where feeders run. Knitting maintenance issue; washable when fresh, permanent when set. Buyer check: white-sole programs catch it fastest (the white-sole logic).
8. Weight off-spec. The pair weighing outside the spec sheet's tolerance — the spec sheet carries the number. From yarn count drift or knitting density. Major: weight is the cross-check on everything (the locking triplet).
9. Boarding fault / size out of tolerance. The sock pressed or steamed off-dimension — length or width outside the grading table. Finishing step. Buyer check: flat-measure against the size chart. Major when fit is the product.
10. Cuff relaxation. The cuff failing to recover — bagging after one wear or one wash. Elastic quality or structure (recovery as a spec). The honest test is wear plus wash, not a fitting; majors show up in returns, so catch them at the PP sample.
11. Grip peel. Silicone grip detaching at edges or lifting in dots. Application-process durability (the grip guide's wash standard). Buyer check: flex the sole and look for lifting edges; test wash per the spec. Major — the failure grows with every wash.
12. Mixed size / mixed color in carton. A packing fault: wrong size or color in a labeled carton or inner bag. From packing-line segregation discipline. Severity depends on your customer — retail chargebacks treat it as critical because their system ships what the carton says. The packaging spec and single-SKU carton rules exist to prevent it.
Turning the Glossary Into Leverage
Three habits convert vocabulary into program quality. Agree on severity before production — the critical/major/minor split, in writing, so inspection day grades against a standard both sides signed. Map defects to processes — a report full of seam skips is a toe-closing conversation; lot shading is a dye-house conversation; mixed cartons is a packing-line conversation. Knowing which step owns each defect tells you whether you have a quality problem or a management problem. Feed findings back into the sampling cycle — recurring defects become explicit checkpoints on the next PP sample approval (the sampling ritual), which is how programs get better instead of just grading their failures.
FAQ
What is the most common defect in sock production? Weight and shading drift — both are process-control readings rather than single-piece faults, which is why the spec sheet carries tolerances and the inspection weighs and compares rather than only looking.
How do inspectors grade severity? The standard split: critical (unsafe or unsellable), major (visible or functional failure), minor (cosmetic). Agree on the split in writing before production so grading day has a signed standard.
What does lot-to-lot shading mean and how do I catch it? Two dye lots of the same color that do not match — compare across cartons under the same light. The prevention is the retained color standard and lot management in the color program.
Are oil stains ever acceptable? Fresh marks can wash out; set stains cannot — and the question itself is a maintenance-discipline signal from the knitting floor. White-sole programs catch them fastest; treat recurrence as a factory-housekeeping finding.
Why do mixed-size cartons matter so much to retailers? Their systems ship what the carton label says — a wrong inner bag becomes a wrong customer order and often a chargeback, which is why packing segregation rules are worth specifying in the PO.
Can defects be repaired? Holes can be darned and some finishes reworked, but repair economics rarely beat culling at sock prices — the leverage is in preventing the defect at its process step, which is what the defect-to-process map is for.