Underside of stitch moving around?

[Rylando]

I'm using #69 thread on a Highlead GC0618-1sc and while the topside of my stitches look awesome, the underside moves around at random, one stitch will be perfectly in line, and the next will be a smidge above it, and it's driving me nuts! Attached is a picture of the wonky backside of stitching on this wallet I've made for myself, 4 layers of 3/4oz veg tan, while the topside looks just fine to me the bottom side like I said keeps "moving around".

Any idea what is causing this? I can't seem to find any similar issues when searching the forum.

 

 

Edited August 31, 2020 by Rylando
Attached better photos

[Hildebrand]

No expert but best guess is the leather is tipping into the hole in the sewing machine as the needle pushes down, and it is doing this in varying amounts.  I have to be very careful when I sew holsters that are double thickness plus a welt down the seam or the back doesn't match up with the front and it will vary like yours does.

Todd

[JJN]

Just a guess. It looks like the underside stitches that are 'off' have the knot very close to the surface and the thread is pushed to one side as it comes out of the knot. I cannot see the knot on the straight stitches. Maybe tighten the upper tension a little to bring the knot up higher in the leather more consistently. Check the bobbin winding and the upper and lower thread path to see if something is causing the tension to fluctuate.

Also, maybe your needle is deflecting as you sew. Make sure the leather is feeding straight without any side pressure on the needle.

[Rylando]

Thanks for the replies guys, after I made this last item I switched it over to #138 thread and didn't have any issues like shown. Gonna switch it back to #69 thread this week and play with it some more.

[CowboyBob]

What type of needle are you using?