Overlock Machines
Thread used to overcast edges of fabric should "blend" with fabric (light
threads on light colors - darks on dark fabric).
Due to the number of spools of thread needed on an overlock machine - all do not need to
match exactly. The thread which stitches the seam (if used) should match the fabric
as in regular machine sewing.
SECURING CHAIN ENDS
* Unweave tail chain - tie ends into knots.
* Thread chain tail through a large eyed needle and bring tails back through the seam stitches.
* Use "Fray-check" or similar product.
* Or secure when sewing over the end with another line of stitching.
* Stitch width should be appropriate for fabric - with balanced tension. Upper and lower looper threads should lie flat on their respective sides and lock with each other on the edge of fabric.
With overlock machine - you can do a seam finish on the edge of each seam. The cutter blade will make the seam less then 5/8", but this is acceptable.
In some cases - seam and edge finish is done in one step leaving seam allowance about 1/4" wide - this is also acceptable if appropriate for the style of garment.