Juki 1541S Stitching Not Secure

[leahmarkman]

Hi Everyone! 

I just recently started my adventure learning my way around an Industrial Sewing Machine. I have a Juki 1541S. I finally thought I got my tension and timing correct, but my stitching isn't secure. When I backstitch, sometimes the top thread shows through and often my stitching can be pulled apart even after I backstitch. Or I'll pull the bobbin thread to test the stitch and a loop of top thread will appear. Any suggestions. 

Ok, last question. I sew lightweight leather mostly in layers. 3-5 oz, rarely do I sew veg tan together. The needles that came with my machine look gigantic. Groz-beckert 135x17 DPx17, 2 nm 160/23 R. Is this the correct size recommend for my material? I'm also using V69 on bottom and V92 on top. Someone mentioned that I should try lighter thread as the bobbin to help with tension. Is this right in my assumption to do this. 

Thank you! 

Leah 

Edited August 14, 2020 by leahmarkman

[Pintodeluxe]

Try a #19 or #20 needle for that 92 weight thread.  You may also have to increase bobbin tension, then re-adjust the top tension for a balanced stitch.

These two changes can help lock in your stitches better.

[leahmarkman]

Thanks I'll go to a sewing store tomorrow and try to get some! 

[chrisash]

Have a look at this chart it matches all combinations of needle size to thread size

https://www.tolindsewmach.com/thread-chart.html