stadard rotary treadle tension
 

the bobbin tension is too tight and adjusting the top doesn't help. I only have 1 bobbin case the machine has a coffin top and is very early I believe. the bobbin case has no lever to hold on to it is just 1 piece of metal with a spring with a screw. .the top stitching looks nice but underside is jumbled.

bobbin tension sets the top stitches. Leave it alone. Does your tension for the bottom stitch look like this?

https://www.quiltingboard.com/member...38-606501.html

.that doesn't look familiar. the bobbin case has a screw to adjust tension. the top tension adjustment is on side of the left arm of machine. when turning it, it doesn't seem to do anything yet the top stitch is nice looking.

I have a standard rotary treadle, there is a screw on the bobbin case you can turn to adjust the tension. I set mine so that when i dangled it from the thread, a sharp tug will get me between an inch and two inches of fresh thread. That usually gives me a good starting point to make minute adjustments...but the tension on that machine has always been decent for me.

According to the manual for a Standard Rotary, the top tension is to be regulated only when the presser foot is down. It also says that the bobbin tension rarely needs adjusting as is "self-adjusting." Have you tried sewing with two different colors of thread? Is the top thread looping on the bottom? Is the bobbin thread flat? Maybe the tension assembly needs cleaning? Is the thread going between the tension discs (while presser foot is up)? I like the video about upper tension at https://www.youtube.com/watch?v=WxtQO2XSB4s

Maybe a picture would help diagnose. We like pictures. In order to post pictures on Quilting Board, you will probably need to reduce or compress the picture to a file size that is smaller than 2MB. How to post images can be found at https://www.quiltingboard.com/attach...020-01-17-.pdf
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I have found that only the big red "reply" button works to give me the paper clip icon to work for adding pictures.

Janey - Neat people never make the exciting discoveries I do.
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