Not Leather but it is a sewing machine question!

[5teve]

Hi All

As every google search about my issue seems to point me toward this site - I figured registering and asking may be the way to go. I dont work with leather just sunbrella etc for personal boat canopy use.

I have a Jiahe sewing machine which is a servo (built in) digital clone of the typical GC0303 - I am using PTFE thread on my latest project (and polycarbonate) and have 2 issues. 

Issue 1, I cannot get the upper thread tight enough. I cant pull it by hand and its still not able to pull the bottom thread back through. The bobbin has its tension set so it drops down gently under its own weight. I end up with an almost flat bottom thread and the upper thread lopped totally round this thread. (certainly not buried half way into the material as it should be ideally)

Issue 2, top thread is shredding. I have read a number of topics on this, it could be the way i am rotating the thread around the upper plates (flat ones with 3 holes in) could be the hook catching the needle, burrs on the hook or a million other things. It certainly seems to be worse on the higher upper tensions.

Can anyone point me to a guide / videos about setting this type of machine up.. I would take it into a shop to get it set up, but i'm stuggling to get any kind of answer of availabilty from anyone local here in perth australia.. I'm normally fairly handy and have a go at most things and have what appears to be a mostly accurate typical GC0303 manual - unfortunately the machine i have seems to be missing some of the markings on various parts that the typical has!

 

Any help would be greatly appreciated!

Steve

[kgg]

27 minutes ago, 5teve said:

I am using PTFE thread on my latest project (and polycarbonate) and have 2 issues. 

What size of thread with what size of needle are you using?

Also a few photo's of how you have your machine threaded maybe of some help.

kgg

Edited November 22, 2023 by kgg

[Wizcrafts]

Whenever you have top thread not pulling up on the bottom, despite increasing the top tension and reducing the bobbin tension, move up one or two needle sizes. The bigger hole may reduce the friction enough to pull up the knots.

Since you are sewing synthetics, you should use round point needles. Both Schmetz and Gross Beckert make special needles to make it easier to sew difficult materials and threads. The Schmetz Serv 7 needles have a bigger eye space. GB makes a higher end needle type they call Gebedur which are coated with titanium. See if you local dealers in Australia carry these needles in the system used in your machine.