Reverse Stitch Issue

[baileyuph]

A question: 

Machine:  Pfaff 545 w/backup stitch

Thread:  In this case - using #69 (thread unique?  doubtfull)

Forward sewing stitch and tension appears to be a go.

Been experiencing thread knotting when changing direction. 

Have noticed take up tension issues but could be body english  with the knee lift - working
in a hurry?

Just don't know, for sure what is causing the problem.

Any ideas or experience similar?

Doyle

[Darren Henry]

I use a 226 Consew that can do the same thing. It wants to come to a dead stop (even for a fraction of a second) before shifting into reverse.

The most common cause of this problem is my not fully depressing the reverse lever. Some times that is due to "stuff" sitting on the machine under the lever----some times I just get distracted and only give it a half hearted swat.

[baileyuph]

Hmmm, good point Darren.  Body english or whatever I need to run more test to determine what I can.  Also, you have me wondering if possibly I was not using the reverse lever (knee lift and slide material technique) on the 545 because my 225 doesn't have reverse and "knee lift and slide" is used t here instead. 

More testing is needed indeed - it will help to analyze the tension take up spring and does the thread get hung up or?

Perhaps extending the testing to include my 1245 might give clues??

Workload lately has driven - pay the bills.

Thanks for the caution of being careless, very possible.

Doyle

[sofadoc]

Are there any recent changes to the bobbins that you're using? Do you wind your own, or use paper shell pre-wounds?

Just a theory, but if the bobbin is slightly undersized, it might cause a backlash when switching quickly from forward to reverse.

[baileyuph]

Bobbins?  I wind for both Pfaffs, I think the bobbins are the same size, but have kept them wih their respective machines.

Soon as I get through this wave of work and have a few minutes, the plan is to do more testing.

Doyle

[Mojo]

I just experienced this headache on my long arm machine. What everyone says can be the culprit.
I did find that if I started reversing with the needle in the fabric everything was OK. If I started with the needle out of the fabric it would cut the thread.

I replaced the take up assembly and it still did it. Changed tension settings and it still did it. Then I realized it only did it when I was using a welt foot. I changed the foot to my binding foot and the problem went away. I believe the hole in the needle foot is too small and casing the thread to frazzle and cut.

Chris

[sofadoc]

Then I realized it only did it when I was using a welt foot. I changed the foot to my binding foot and the problem went away. I believe the hole in the needle foot is too small and casing the thread to frazzle and cut.

I have 2 different styles of double welt feet. When used by themselves, either set  works fine. But when used in conjunction with my DW folding attachment, one of the sets will cut the thread every time. The other set sews (with the attachment) perfectly.

I stopped trying to figure it out. I just go with what works.

[Darren Henry]

Good call Chris. I had forgotten that the welt foot for the 226 had a micro-bur on the inside foot. It sewed fine, but when you pulled the project out from under the foot it cut the thread. If Doyle had one of those micro burs in the right spot on his foot it could be the culprit. I polished mine out with some valve grinding compound on a coarse cloth.