Hi all, not sure if this is the right spot for this as I am new to this site. I have a Cowboy 4500 that sews great and I noticed a while back the thread freying slightly as its pulled up from the shuttle area and up through the needle. I have checked all parts for burrs and have buffed certain areas so burrs are rulled out. My problem is ive notice the needle binding on the upstroke much like it is struggling to pull thread up through the leather. It makes a crunching/pinching groan on the upstroke and when run at very slow speed it will bind up and Slip at the belt on the motor I think. Has anyone ever experienced this problem or is it normal on this machine?