Abstract: The present invention permits the testing of the sewing characteristics of various types of sewing threads under conditions which simulate the normal conditions encountered when performing various fabric seaming operations in the conventional manner. The testing of the sewing characteristics of the sewing threads is carried out in an economical manner by using narrow test strip fabric so that the test results can be ascertained in a short period of time. The method and apparatus of the present invention permits various types of sewing threads to be subjected to the identical and repeatable conditions so that an accurate comparison of the sewing characteristics can be made. The sewing thread test can be carried out on relatively inexpensive narrow test fabric strips which are fed to and past the stitching needle of the sewing machine in various angular paths of travel relative to the needle and at preselected variable speed rates.

Abstract: A fiberoptic bundle has one end disposed in the bed of a sewing machine in opposition to the stitch formation region below the throatplate. A strobe light for periodically illuminating the region and a camera for recording visual images of the region are coupled to the opposite end of the fiberoptic bundle. The end of the fiberoptic bundle within the sewing machine bed may be provided in guidepaths for viewing the stitch formation region from different viewing directions, preferably 90.degree. apart. A load cell is disposed on the side of the sewing machine for recording tension transients in the thread en route to the needle.