Abstract
The factors influencing the tensile strength along the lock stitch type seam sewn in bias direction of woven fabrics were studied in order to find the methods to increase the seam strength. Two test pieces of cotton broad and calico fabrics, 10 cm long by 1.5 cm wide, were sewn together in bias direction using the cotton sewing threads # 50 and # 80 and their tensile strength along the seam line was measured by Schopper tensile tester varying the pitch of stitches and the sewing threads tension.
The results obtained are as follows :
1) The seam strength is affected by the conditions of the tension of top and bottom sewing threads.
2) If the thread tension is well-balanced, the stronger the thread is, the weaker the tension is, the shorter the pitch of the stitches is, the stronger the seam becomes. The less flexible the fabric is, the less weak the seam is.
3) Adding several pieces of papers on the seem line, doubling seam lines or widening the fabric increase the seam strength.
4) If the tension of top and bottom threads is extremely violated, the thickness of the added paper and pitch of stitches have no effects on the seam strength.
