Pfaff 1445 different length on reverse and forward stitches

[Swedish]

Hi

I recently bought a Pfaff 1445 with EFKA V720. I'm having some problems with the sync between reverse stitch and forward. When I set stitch length to 4mm the forward stitch is correct but the reverse stitch is 5,2mm long. The same ratio for the whole range from 1mm up to 6mm. 

I have adjusted the feed, feeddog and everything I can think of but still the same problem. 

Does anyone know what the problem can be?

Grateful for all help 

 

[Constabulary]

I can´t help but just today I read in a Pfaff mechanics instruction manual (for Pfaff 332) that ex factory there is a 10% difference between F and R stitch length in order to not pierce (damage) the thread of the forward stitch. This has nothing to do with your machine but from my observations there very often is a difference between F and R stitches on different machines - maybe for a purpose?

Not sure how different the machines are internally but externally the Pfaffs often have the same stitch length lever so maybe this is an idea for you:

https://www.youtube.com/watch?v=wtT7QejY2eQ

Edited May 26, 2023 by Constabulary

[Swedish]

Ok, that could be the case. Seems a bit strange on a machine that is made for heavy duty and leather where the stitches are visible and often a part of the visual effect. On a machine for fabric where the stitches aren't as visible I can understand the part of not damage the thread.