Patcher problem bending My bobbins

[winniepops]

I bought an SL-781 patcher to start doing some leather sewing but now I have a serious issue with the bobbins getting ruined.

The machine came on a terrible old table so I swapped it out for a good industrial one and replaced the original clutch motor with an adjustable servo motor for better speed control. It actually ran fine with the small motor and even with the faster clutch motor, although it was too fast to use much. Now, with the new servo motor set to run nice and slow, it starts okay and the needle grabs the bobbin thread just right. But then I hear a loud noise and the machine gets stiff and when I check the bobbin area, the metal top of the bobbin is bent completely down. I’ve looked at the needle path and it seems to go where it should and the manual doesn't mention anything about this problem.

Since it worked before, I assume the timing is correct but I'm stuck now. Has anyone ever dealt with a bent bobbin on an SL-781 or maybe a Singer 29K machine and is there simple fix for it?

 

[WindWhisperer50]

hi @winniepops are you using the correct large needle size for that heavy machine?
If you're using a needle that's too thin for the thread, the thread loop isn't forming correctly, and the needle is likely deflecting and hitting the bobbin case as it enters the shuttle area

 

[skull panda]

That's a hook assembly being severely out of sync. While the needle still manages to catch the thread initially, the timing difference is likely causing the revolving shuttle hook to hit the metal edge of the stationary bobbin case as it spins. That can completely crush the bobbin's top edge, especially at lower speeds where the impact force is more noticeable.

What you can do is to retime the hook assembly to the needle bar. Do you know how to do it?

 

[winniepops]

The needle is fine. Can you teach me how to retime the hook assembly to the needle bar? If you can share a tutorial it would be great.