OCTOBER 2008
General Seaming
Stitch Density
A minimum of 12-14 stitches per 2.5cm should be used on all lock stitch seams and chain stitch seams
Overlocking operations should provide good cover for the fabric type in use without causing thick edges – Three thread overlocking is to be the norm but two thread overlocking may be used where exceptional circumstances occur. Stitches should be 10 - 12 stitches per 2.5cm
Buttonholes require a minimum of 16-18 stitches per 2.5cm to provide good coverage of the cut edges, unless fabric or otherwise require more or less stitches to be agreed with the technologist during sealing.
Felling stitches should be 8 to 10mm pitch with a level of pick up to prevent breakdown while avoiding any show through onto the outer surface of the garment
- unless the fabric or style requires some modification to these guideline.
Thread Type
Sewing threads should be appropriate for the fabric in use and its performance.
The thread count and sewing needle sizes used should also be correct for the relevant type of seaming in use.
Core spun polyester threads should be used were possible.
Spun polyester threads are not recommended due to their lower thread strength.
Other threads used for such as embroidery, embellishments or other decorative stitching should be compatible with the fabric and the garment after care recommendations.
Seams
All main seams on tailored garments should be 1.5cm wide and be pressed open.
Pressed open back rise seams on trousers must be double stitched or two thread chainstitched as this seam can be put under a large amount of stress.
Safety stitched back rise seams should be of the 5 thread overlock type to provide movement and security.
Where 5 thread or 4 thread overlocked seams are used they should be pressed over cleanly in the appropriate direction for the panel or part of the garment where used.
Where garments parts are overlocked together, specifically along seams that are to be put under any stress or stretching, it is required that you ensure a consistent amount of fabric is taken in to these seams to avoid seam breakdown or seam slippage occurring during wear.
Single needle lockstitch seams should not be used for any jersey or high stretch fabrics as the seams will bust if stretched. Single needle chain stitch seams or linking seams are required for their flexibility.
Single needle, twin needle chain, overlock or cover stitch seams should be used on jersey fabrics for stitching cuffs and hems
Embroidery and Embellishments
Where embroidery is used:
All embroidery should be double knotted, leaving only a minimum thread tail of less than 1cm, which then needs to be neatened.
Where embroidery is used across a garment body then the grading of the garment should be considered with the repeat of the embroidery in mind.
When using viscose or shiny threads the thread should be secured with extra knots to ensure that the stitches are secure. Furthermore a 1cm tail should be left to ensure that the thread or stitching does not run back through the knot.
If washed garments contain embroidery, they will need to have been assessed for colour marking. The thread tail length may need to be longer, between 1.5cm to 2cm before wash and the freyed ends trimmed neatly after wash. This situation needs to be assessed during wash testing.
Where beading is used on a garment for decoration, the following should be taken in to consideration:
The Toxicity of every bead should have been tested to meet international safety guidelines.
Checks should also be made to test all beads for their colour fastness to avoid fading during wear or during aftercare, particularly strong colours and reds.
Viscose sewing threads should not be used.
Threads should be doubled when hand sewing beads and embelishments.
All beads should be secured after every 3rd bead by a knot or a back tack stitch to prevent beads falling off.
Do not use glass beads which have rough edges as they will sever the sewing thread and fall off. All glass beads should have smoothed edges.
If beads are attached to the waist of a garment, then the stitching should have sufficient stretch to be compatible with the waist stretch of the garment.
Spare beads are required to be supplied with each garment, to be specified by the buying team and supplied attached to the garment in a small poly bead bag.
Fastenings
Button Attachment
ALL buttons should be securely attached using the appropriate method for the type of button in use. This will include lock stitch, chain stitch and hand sewing methods.
Buttons should have equi-distant attachment holes as specified during sampling. Any inconsistency with this can cause needle deflection and slip stitching
All buttons should be attached using a neck or shank length of suitable length to suit the thickness of the garment parts they are closing to avoid a tightly sewn button distorting the buttonhole area.
All buttons with a neck or shank should have the neck neatly whipped to secure the button and avoid its drooping when unfastened. The whipping can be by machine or by hand but should be neat and without loose thread ends.
The only exception to these guidelines are for two holed shirt and blouse buttons that go through a straight buttonhole on thin fabric. These buttons should have a small neck of about 1.5mm to prevent the button splaying the button hole.
The two hole button attachment thread should be sewn in the direction of the button hole, not across it.
Where buttons made from shells are being considered, care should be taken to ensure their durability from cracking and snapping. These are more likely to be attached using hand sewing when a quality check can be made on each button before its use.
Spare Buttons
Spare buttons should ideally be place in a small re-sealable poly spare button bag.
They may be attached onto the care label in some cases wuith the agreement of the buying team, making sure that no information on the care label or any care symbol is covered.
The specification for the supply of spare buttons is as follows:
1 spare button wherever 1 button or more have been used.
1 spare button of each size if different sized buttons are used.
2 spare buttons in each size where cloth covered buttons are used.
BUTTON ATTACHMENT
In addition to basic stitching faults the following causes also contribute significantly to the failure of button attachments and should be noted when selecting the type of button and the sewing method:
Thread unraveling from buttons sewn using a chain stitch machine.
Fabric tearing where the button is attached on finer and some washed fabrics.
Whipping threads coming undone on buttons subjected to frequent fastening and unfastening.
Buttons breaking away from the thread due to poorly selected buttons or incorrectly set machinery allowing the needle to weaken the attaching holes.
Threads breaking during wear caused by sharp button edges or from chaffed threads due to incorrectly set machinery or poor thread selection.
Other Fastening Types
Pressed Metal buttons with sharp holes must be avoided as this can break the thread.
Hooks & Eyes of various sizes may be used to either support a zip closure, to fasten a waistband of in larger sizes, fasten fronts of outerwear. Whatever method is used to attach these fastenings they must be secure and neatly stitched without loose thread ends. Where the attaching parts are sunken into a seam then the internal attaching system must be strong and durable.
Hooks and Bars used to fasten trouser waist bands, which are applied using a stapling system, must be applied using the correct equipment from the supplier of the component parts. The staple barbs must all be well stamped over into the recesses of their backing plates.
All metal fastenings and attachments must be nickel free.
Buttonholes
To be lockstitch format.
To be either, and agreed with technologist at pre-production meeting:
Cut before eyelet type with gimp and bartacked at end, for stud button & 4-hole button
Cut after fishtail with gimp, for stud button & 4-hole button
Straight cut without eye, for 2 hole buttons
All buttonholes to have sufficient stitch cover to avoid fraying
Waistband buttonhole to be positioned horizontally and central on the band 1.0 CMS in from the band edge, unless agreed otherwise