*1.5 is a factor based on the average loop strength ratio of most sewingthreads. =10 SPI X 4.0 lbs. X 1.5 = 60 lb. strength 401 Chain stitch Estimated Seam Strength =SPI X Thread Strength (lbs.) X 1.7 ...
Some results have been hidden because they may be inaccessible to you
Show inaccessible results