The LH-3500A, with a large hook for jeans, is provided with a "large hook" which is 1.7-fold larger than the standard hook provided for the model launched this last January. With the large hook, this machine helps reduce the frequency of bobbin thread changing when sewing jeans or the like with thick thread. In addition, the curvature of the thread path has been minimized to improve the feed locus. This promises a strong and smooth feed of the material even when sewing heavy-weight materials for jeans.The machine can make the most of the advantageous features of the large hook. The organized split needle bars which enable either the left or right needle to stop independently of the other can be changed over by simply operating the lever, thereby saving labor in corner stitching.