Machine tension questions
 

I am using my DSM to sew some covers for tools and gears for an airplane that my son is helping to restore. The material is duck and I am having a real problem getting the tension correct. There are three layers of fabric and the upper thread is looping through to the back and the bobbin thread is laying flat on the fabric. I have adjusted the upper thread tension all the way from 3 to 9 but the problem still exists. Do I need a commercial upholstery machine to make these? I am using a #69 weight nylon thread with a jeans needle in the machine. Need help before I throw the whole project out the window! LOL
This picture shows the top of stitching on wrong side of fabric
[ATTACH=CONFIG]512663[/ATTACH]
This picture shows the wrong side (bobbin side of fabric) which will be the upper side when project finished. Hope this makes sense.
[ATTACH=CONFIG]512664[/ATTACH]
Thanks for your suggestions.

I always check my manual. I have nothing else to suggest.

Usually you need more of a industrial machine to sew fabric for an airplane instead of a DSM. The thickness may just be too much for your machine.

ManiacQuilter2, I think you might be right. I have tried different threads, tension, etc etc. Nothing works. Now I am wondering if an upholstery place might rent me time on one of their machines.

I'm not sure what your machine is, but an older (mechanical/metal) machine should sew this. I have a 401J and it would handle it. I can't say re the newer electronic ones because I haven't tried to sew very heavy materials.
It might be cheaper to buy an older machine vs renting on upholstery machine if you could audition your fabrics on the machine.
(Guessing that this isn't the first or last project you may be helping with???)

My ugly old Singer 15-75 beater machine would handle that just fine. I would put in a size 18 needle - test through a few layers of fabric, adjust and she would sew it like it is nothing.

Have you tried using your walking foot and treating it as thick sandwich?

Might need heavier thread, if using a jeans needle, try jeans thread and as dottymo suggests try a walking foot. I quite often sew this kind of fabric and multi layers, the other foot that might work better is the roller foot as your fabric may be slipping as its too much for the feed dogs alone.

My mother used to recover airplane seats and used her Singer 201 portable. It would sew through anything. It's a 1950 model and heavy as lead.

That is a thought. I will pull out my Featherweight and see if it will handle it. My Pfaff has an IDT that I used with it but did not seem to make much difference. Thanks for all the suggestions. Love this forum!