The tech pack hardware specification, usually the trim sheet, is the part of a tech pack that brands give the least attention, and it is behind many of the most common production errors: buttons in the wrong colour, snaps that do not fit the press die, nickel eyelets on a babygrow. The cause is almost always an incomplete spec. "Metal button, gold, 20" is not enough. This article gives you a ready-made template and explains why each field matters.
Why metal trims need their own specification
Fabric and thread are described with a handful of parameters. Metal hardware has many more variables: size in mm or ligne, shape, body material, tack or prong material, plating, logo and technique, attachment method, compatible machine and safety requirements. Each can be interpreted differently by a supplier. On top of that, custom hardware needs a mould and an approved sample before production, and an error found after the mould is cut costs both time and money.
Metal buttons with a pink finish 6104047 Col 255 – 22 mm handmade
Snap fasteners 0006 – mini, with a flat cap
Classic sew-on snap buttons SP517 – 15 and 23 mm Nickel FreeTrim sheet template
| Field | What to record | Example |
|---|---|---|
| Trim code | Internal code repeated in the style's BOM | TR-03 |
| Description | Exact part type | Cast shank button |
| Supplier code | Article number if it is a stock design | From catalogue |
| Size | Diameter in mm and/or ligne, height, inside width for rings | 20 mm (32L) |
| Material | Body and back part separately | Zinc alloy; brass shank |
| Finish | Name plus reference sample or code | Antique brass, per sample R-12 |
| Logo / artwork | Vector file, technique, logo size | Debossed, 12 mm, file logo-btn.ai |
| Placement | Location and distance from edge/seam in mm | Front, 15 mm from edge |
| Attachment method | Sewn, pressed, die | Sewn, 4-wrap thread shank |
| Quantity per garment | Count per size | 2 x 20 mm + 6 x 15 mm |
| Compliance | Nickel, lead, other requirements | Nickel-free; REACH |
| Approved sample | Date and reference of the golden sample | GS-03, approved |
| Tolerance | Permitted variation in size and colour | ±0.2 mm |
The fields most often left out
Finish: a name is not enough
Finish names are not standardised. "Gunmetal", "antique brass" and "black nickel" from one supplier can look quite different from the same names at another. The only reliable method is a physical reference sample, such as a button, eyelet or plate in the approved colour, which you keep and send with every order. In the trim sheet, record the sample code, not just the name.
Size: mm or ligne, but clearly
One ligne is 0.635 mm. If you write in ligne, add millimetres too. For snaps, eyelets and jeans buttons, the size must match the press die, so state the system or model your factory uses.
The back part
On jeans buttons, rivets and snaps, the back part (tack, socket, burr) is a separate component. Tack length must match the fabric thickness at the attachment point; a 14 oz denim waistband with interfacing needs a longer tack than an 8 oz shirt.
Compliance
EU REACH (Annex XVII, entry 27) limits nickel release from articles in direct and prolonged skin contact to 0.5 µg/cm² per week. That covers jeans buttons, snaps, belt buckles and any hardware touching the skin. Entry 63 limits lead in accessible parts of articles that children may put in their mouths to 0.05% by weight. If you sell childrenswear, also specify a pull-strength requirement for snaps; many retailers work to internal standards, often around 90 N. The full REACH text is available on EUR-Lex.
Placement and attachment: draw it, do not describe it
"Buttons on the cuff" leaves too much to interpretation. Add a flat sketch with arrows and measurements: distance from the cuff edge to the first button, spacing between buttons, overlap. For eyelets and rivets, give the centre point relative to the seam. For snaps, state which part goes on top (cap and stud) and which below (socket and post), so the factory does not swap them.
Example: the metal trims on a denim jacket
To see what a completed trim sheet looks like, take a classic denim jacket. It carries six kinds of metal parts, each on its own line: 17 mm jeans buttons on the front (6 pcs), 14 mm buttons on the pockets (2 pcs) and cuffs (2 pcs), 9 mm rivets at the pocket corners (4 pcs), adjuster buttons on the back (2 pcs) and an optional metal label. Each line states cap and tack material, a finish matched to the same reference sample, logo per drawing, distance from the edge in mm, and tack length according to the number of fabric layers in that zone. The factory then knows the cuff button passes through two layers and the waistband button through four, and prepares the right tacks.
Checklist before sending
- Every metal part has its own line and code, repeated in the style's BOM.
- Sizes are in mm (and in ligne if that is your supplier's convention).
- The finish is defined by a reference sample.
- The logo is attached as a vector file, with size and technique.
- Attachment method and machine or die are stated.
- Nickel and lead requirements are written explicitly.
- Quantity is calculated per garment and for the whole order, with 3–5% extra for attaching rejects.
- There is a field for the sample approval date.
Tip: at the end of each season, review the trim sheet with your factory. Every attaching problem, from bent tacks to misplaced eyelets, signals a field that needs tightening for the next order.
Common mistakes
- A photo from the internet instead of a reference sample.
- No back-part size for jeans buttons and eyelets.
- Different codes for the same part across styles in one collection.
- A nickel-free requirement added after the sample was approved, forcing a new sample.
Working with Bul-tex
Bul-tex manufactures and supplies garment trims and works with brands that send a trim sheet; the more complete it is, the faster we can prepare a quote and a sample. You can browse stock designs in buttons, snap fasteners, eyelets and buckles. For custom hardware, send us your specification, and read more about the process in our manufacturing articles.
