I have a Tacsew T111-155 machine i am trying to sew about 8oz leather i am useing a # 23 needle it gos through the leather with no problem but i keep breaking thread # 92 seems to break less then # 138 MY thread is marked T90 and T135 high speed bonded nylon.the slower i go the less it breaks may be some one can tell me what to do thanks Charlie K