New to sewing on a machine (Cobra 26) - 1st try and corners and botton were a disaster / Any advice ? - see pics

[JJCE]

Bottom - Disaster ( Straight lines were very different from the stitching on top - much more clean on top ) 

Corners - Complete disaster  

Any advice on how to turn around on wide round corners ? or Why the bottom stitch was not as clean as the top ? 

[kgg]

7 hours ago, JJCE said:

Why the bottom stitch was not as clean as the top ? 

A couple of questions and suggestions.

1. What size of thread are you using??

2. What size of needle are you using??

There is a good needle to thread chart:  https://www.tolindsewmach.com/thread-chart.html

Going around a tight corner you may want to hand-wheel through and after each stitch raise the presser foot ever so slightly. Just enough to turn the leather a touch. I do this with the needle just on it's way up from the bottom dead centre position. That allows the needle to hook the bottom thread otherwise you will skip a stitch.

The tension on your top thread is not high enough to pull the bobbin thread into the leather so you get a seam like your last photo.

Suggestions:

1. Check you are using the correct needle for the size of thread you are using.

2. Check your top thread path from the thread spool to the eye of the needle is correct. 

3.  Suggest you first check the bobbin thread tension, do a drop test.

4. Increase top thread tension as needed. Use scrap leather in the same thickness as your project and do a few four to six inch seams.

5. At the start of your stitching hold both threads for the first three stitches and while still holding the threads reverse back to lock the threads then do your seam otherwise there is no back tension on the top and bobbin threads. You need a thread anchor point otherwise you can get some funky stitching as the thread tensions will vary.

6. Back stitch the end of your seam to lock the stitching.

kgg

 

[friquant]

When I was learning to drive an industrial sewing machine, my favorite thing to practice on was actually corrugated cardboard. Ubiquitous, cheap, thick, stiff. You can cut two pieces and stitch them together. Or you can just stitch on one and make a pattern. At one point I was drawing curvy lines (with some tight corners and some loose corners) on the cardboard first, then seeing how well I could follow the line of ink.

For practice, I enjoy having a different color top thread than bobbin thread. That makes it easy to see tension discrepancies.