Trimmer ONLY cuts bobbin thread

On one of our single head machines, the under trimmer only cuts the bobbin, and not the top thread. The puller hook fires and grabs the top thread, but it is still attached. This is a Tajima TMEX C1201. I does have all four required parts, the knife, the bottom thread clamp and the two clamp/knife pieces on top of the knife. If I put a piece of thread into the knife set and fire an ATH, the thread will cut. The fork that clamps the thread to the bobbin works and is in proper position. This is a new clamp set. It worked OK for an hour or so after installation, then quit working. Anybody have a clue? I'm stumped.

As a quick BTW, I have left ARTCRAFT and am now over at AMPRO (American Process Lettering).

Thanks,

Jamie Malerman

Location: 
United States

hey Jamie, not sure if you got sorted on this problem, it may be the rotary hook, if it has a burr on it , it will distort the triangle at trim timing and miss the leg, if you have a new hook throw it in the machine.
you have taken the needle plate off and pulled the moving knife to the left ? then put the thread into the front side of the knife then closed them to see if it trims? and you say the picker is set correctly, travelling all the way until it makes slight contact with bobbin without any resistance?

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onet wrote:
hey Jamie, not sure if you got sorted on this problem, it may be the rotary hook, if it has a burr on it , it will distort the triangle at trim timing and miss the leg, if you have a new hook throw it in the machine.
you have taken the needle plate off and pulled the moving knife to the left ? then put the thread into the front side of the knife then closed them to see if it trims? and you say the picker is set correctly, travelling all the way until it makes slight contact with bobbin without any resistance?

also did you mean you replaced the complete picker assembly? I had a customer do the same then I spent 2 hours trying to figure it out, then compared the old and new and they were different...call me if your stuck
brian 253 8332157

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