Pfaff 345 upper thread shred

[paukenman]

Hi All,

I have a pfaff 345. With 138  thread on top and bottom the upper thread shreds with anything other than one layer of 5oz Leather. It doesn’t always break but it ends up unravelling and binding on the channel side of the needle. 
 

looking at the hook it seems it is grabbing the thread right in the middle. Not sure how much closer I can move the hook to the scarf!

any ideas? Thanks in advance!

[Pintodeluxe]

Is the check spring tension and position correct?

Do you have a needle bar thread guide on your machine? 

These are the things I check if I experience upper thread shredding.  

[Constabulary]

Have you tried a new needle? Check the thread path for burrs and rough spots.

[paukenman]

I do have a thread guide and it is a new needle. It only shreds in thicker stock and especially in  reverse.  
 

the reverse stitch length is also much shorter than forward length. Trying to figure out that adjustment.

 

it seems the hook might not be close enough to the needle. 
 

thanks for the input! 
 

if anyone knows how to adjust the reverse stitch length please let me know!

Edited September 24, 2020 by paukenman

[Pintodeluxe]

Hook spacing issues can definitely cause your problem.  Instead of consistently catching the loop, the hook will sometimes split the thread.