Pfaff 5642 Puller Usage

[Dave9111]

 

I bought a Pfaff 5642 two thread chainstitch machine.    Yes, I know its a 401 chain stitch machine (like the hem on jean pant legs) but I have wanted to try one out after seeing so much commercial canvas sewn with one.  

I think its a late 80's machine.  

Not having a bobbin is a big advantage when doing larger canvas projects.   This machine is built like a tank.  I've seen engine blocks with thinner cast iron.

This machine has a built in fabric puller.   The bottom roller is knurled steel and the top roller is soft rubber.   When running the machine by hand, its obvious that the puller lags the feed dog.  Material begins to bunch up in front of the puller.

I pulled the center cover off the machine, and the shaft that drives the feed dog is geared to the bottom puller drive roller.   So it appears that the puller "pull" is a fixed amount for every stitch.  

Does that mean that the puller dictates the stitch length?   I'm new to "pullers".   If I make the puller drive roller larger in diameter, more material will be moved for each stitch.  I could make a bigger drive roll or temporarily wrap friction tape around it to make it bigger.  

What do you think?   

Per the manual, the stitch length is adjustable per a handwheel at the right side of the machine but that doesn't seem to be doing much.  Perhaps I need to tear into that to see if something has fallen out, disconnected itself etc.  

Every machine I have purchased has had something wrong with it.  This is likely not an exception.  

But at least it sews, nothing is worn loose, and internally it is very clean.  

Thanks! 

 

  

 

 

[Dave9111]

Answering my own question:  I pulled apart the stitch length control mechanism behind the knob.  There is a cam in there that accepts a pin.  The pin moves the stitch length mechanism which changes the looper tensioner and the feed stitch length.  The pin was off the cam apparently.  Putting it back together after cleaning and oiling and I can now change the stitch length and get rid of the fabric bunching in front of the puller.  The puller and feed dogs now work together.  Time to put the machine on a stand with a servo motor.