Custom garment manufacturing: what to specify, what each sample is for, and what goes wrong

A garment has to fit in every size and still fit after it is washed. What to put in writing before you pay a deposit, what each sample proves, and where first runs fail.

Filed under Cut and sew

Short answer: Custom garment manufacturing means a factory makes clothing to your pattern, fabric and size chart instead of decorating a blank. A good quote needs a tech pack, a size spec with tolerances, a named fabric and a shrinkage test method. Most failures trace back to fit approved on one size, fabric that was never wash-tested, or a pre-production sample nobody signed. Fix those three before you pay a deposit.

Custom garment manufacturing has more ways to go wrong than most sewn products, because a garment has to fit a body in every size and still fit after it is washed. A bag has neither problem. This note covers what to specify, what each sample is for, and where first runs usually fail. Our cut and sew note covers where minimums come from, so they are not repeated here.

What to specify before you ask for a quote

A factory can only price what you write down. Send these with the first request:

• Tech pack. Flat sketches, bill of materials, construction and artwork placement. Our tech pack note lists what goes in it.
• Size spec. Every point of measure, for every size, with a tolerance.
• Fabric. Fiber content, weight, construction (knit or woven, and which one), finish and color. "Heavy cotton fleece" is not a specification.
• Wash treatment. Whether the garment is garment-washed, garment-dyed or sold as sewn. It changes the pattern, the shrinkage and the price.
• Test method and limits. Which shrinkage and colorfastness tests apply, and what result passes.
• Labels and packing. Care, fiber and origin labels, hang tags, folding, polybag and carton.
• Quantity by size and color. A size curve, not a single total. The factory uses it to plan fabric.

Size specs and tolerances

The size chart is the document most first-time brands leave vague. An apparel factory's guide gives the plain definition: "Measurement tolerance is the accepted range, plus or minus, that each size point on a garment can vary from the spec." The same guide adds: "Key points like chest, waist, or inseam take stricter ranges—often +/-1cm to 2cm—since these affect overall fit and comfort the most." Treat those figures as one factory's starting point, not a standard, and agree yours point by point. It also gives the warning that matters most: "Never set a tolerance your supplier can’t hit!" A tolerance only protects you if the factory measured its own capability before accepting it.

Write down how each point is measured, too. "Chest" can mean flat across one inch below the armhole, or a full circumference. Two measuring methods can fail a garment that was sewn correctly.

What each garment sample is for

Sample names vary from factory to factory, so agree on what each one is for. The usual order, using the definitions from Techpacker's guide to garment samples:

1. Proto sample. It checks the idea, not the fit or the fabric: "The idea is to solely review the style and design aesthetics, so it doesn’t need to be constructed adhering to the full specifications."
2. Fit sample. "Measurements and construction need to be accurate and correct in order to pass the fit evaluation." It is usually made in one base size, and it often takes more than one round.
3. Size set. The approved base pattern is graded across the range and sewn in each size. One apparel shop's guide names the failure this stage catches: "A poor grade can result in an XL that is simply wider but not longer, or an XS with an improperly scaled neckline."
4. Performance test sample. Pieces go to testing before the run. "The tests can include seam strength, seam slippage, colorfastness, wash fastness, among others."
5. Pre-production (PP) sample. This is the one that binds. "It’s a test run by the factory and they can proceed with the bulk production only when the PP sample is approved by the brand."
6. Top of production (TOP) sample. Pieces pulled once the run has started, and "they are evaluated to ensure that the bulk production is of the same quality as the PP sample".

Skipping the size set saves one round of samples, and the risk is finding a grading error in cartons of finished goods instead. Sign and date the PP sample and keep a counterpart. Our note on why a golden sample does not guarantee lot three explains why the signature alone is not enough.

Fabric: shrinkage comes before cutting

A garment can pass every measurement on the cutting table and fail after the customer's first wash. Two things decide that: how the fabric is handled before cutting, and whether the pattern allows for shrinkage.

• Let it relax. An apparel shop's guide to pre-cutting warns: "Fabric that is cut immediately off the roll without a rest period will result in size and shape distortion after cutting and sewing." Knits are the usual problem. Ask the factory how long rolls rest before spreading.
• Test the actual lot. AATCC 135 and ISO 6330 are test methods for dimensional change after laundering. They tell you how to measure. The pass limit is yours to set. A knit-fabric supplier's buyer guide says: "Buyers should specify which standard to use in their purchase contract." The same guide adds that "for fitted garments or those with strict sizing requirements, 3% is the safer target", and that a relaxed fit can tolerate more.
• Put the result in the pattern. With a measured 5% length shrinkage, the pre-cutting guide's example is direct: "A shirt body pattern that needs to be 28 inches long after washing will be cut at 29.47 inches". A test run on the sample fabric does not prove the bulk lot, so test the bulk roll before the pattern is locked.

Color is the second fabric failure. Ask for lab dips or a strike-off, and approve them under an agreed light source. Fabric from a different dye lot can shade differently, so ask how the factory keeps a garment's panels from mixed lots apart when cutting.

US rules that apply to clothing

Our tech pack note covers fiber, origin and identity labels. Clothing adds more rules that a brand has to plan for, and they still apply when the factory is overseas.

• Care labels. Under the FTC's care labeling rule: "Manufacturers and importers must attach care labels so that they can be seen or easily found when the product is offered for sale to consumers." The instruction must be right for the garment, so the wash test and the label should agree.
• Flammability. CPSC's clothing standard, 16 CFR part 1610, says: "The Standard provides methods of testing the flammability of clothing and textiles intended to be used for clothing" Very sheer fabrics and brushed or raised surfaces are the ones to ask a lab about early.
• Children's clothing. It carries more. Sleepwear has its own flammability standards (parts 1615 and 1616), and federal law requires children's products to be certified from third-party testing. Talk to a testing lab before you sample, not after.

None of this is legal advice. Confirm your own product with a lab or customs counsel.

Where custom garment runs usually go wrong

• Fit approved in one size only. The base size is right, and the ends of the range are not.
• Fabric swapped after the fit sample. A similar fabric can drape, stretch and shrink differently. Refit if the fabric changes.
• No measuring method. The factory and your inspector both follow the chart and still disagree.
• Bulk fabric not tested. The sample lot passed, and the production lot was never checked.
• Inspection only at the end. A problem found at packing is usually costlier than the same problem found on the first day of the line. A pre-shipment inspection should measure garments against the spec as well as look at them, and an AQL sampling plan sets how many.

Where Jack fits

Most programs on our cut and sew page are bags, cases and tactical soft goods. Our soft goods page also covers apparel built to a tech pack at vetted partner factories. Whoever you talk to, including us, ask to see garments that factory has made in your fabric type before you pay for samples. A factory that sews great duffels is not automatically good at a fitted knit.

If you have a garment in mind, send Jack your tech pack or a reference sample and the quantity you have in mind. He will tell you what is missing, and what to settle before a factory quotes it.

Straight answers

What is custom garment manufacturing?

Custom garment manufacturing means a factory makes clothing to your own pattern, fabric and size chart, instead of printing or embroidering a finished blank. You control the fit, fabric and construction. In exchange you take on sampling, grading and fabric minimums.

What do I need to send a garment manufacturer for a quote?

Send a tech pack, a size spec with tolerances, the fabric specification, any wash treatment, the test methods and pass limits you require, labels and packing, and the quantity broken out by size and color. A quote made without these is an estimate that will change later.

What is the difference between a fit sample and a pre-production sample?

A fit sample checks measurements and how the garment sits, usually in one base size and sometimes in a similar fabric. A pre-production sample is made on the production line with the actual fabric and trims. The factory should start bulk production only after the brand approves it.

What is a size set sample?

A size set is the approved base pattern graded and sewn across the size range. It checks that the grading is right, so the largest and smallest sizes stay in proportion and fit as intended, before fabric is cut for the full run.

How much fabric shrinkage is acceptable in a garment?

There is no single legal limit. You set it in your spec according to the fabric and fit. One knit-fabric supplier's buyer guide suggests 3% as the safer target for fitted garments. Name the test method, such as AATCC 135 or ISO 6330, and test the bulk fabric lot, not only the sample fabric.

How this note was made: researched and drafted with AI assistance, checked against the sources listed below and edited at JCH Design & Manufacturing.