MeganMills

I cannot find it now but I know a couple of times I've seen something online to say that in addition to the stitches "meeting in the middle" and the stitches "locking" to create a strong seam (without puckering) another sign of good tension is that when you turn a corner the stitches look the same top and bottom.

A fair proportion of the time mine do - and a fair proportion of the time (on the same line of sample stitching) they don't and there is a little "loop" of the top thread pulled under. (Or - if I adjust tensions the other way dramatically - a loop appears on top.) This pulls the corner/angle stitches "out of square" (or whatever angle it is you're aiming for) on that side and is unattractive when both sides can be seen. And it irks me.

I've been experimenting on my circa 1902-1903 Singer 28K to try to find just exactly when in the stroke of the needle being "down but rising" is the right time to lift the presser foot, turn and pivot as I have a suspicion that if the tension is otherwise lovely in every respect this might be the variable factor that makes some corners great top-and-bottom and others less so.

The green is the top thread. The stitch length is set at the longest setting and I'm using 50wt Aurifil cotton thread. There is puckering in the fabric because the first tests were too loose top and bottom so looked lovely but pulled right out - no better than basting. So I tightened up in the other direction so it locked like crazy but puckered. Then I incrementally notched it down bit-by-bit. (This has meant playing with both top and bottom tensions. The shorter seams closest to the outside corner is the most recent testing. I started on the longest seams.)

No matter what I do a tiny dot of the other colour shows on each side and I'm fairly sure this is simply because if the fabric isn't particularly thick there isn't sufficient "between the fabric" space for the threads to twist around each other between the two. So long as the dots are the same on each side, the seam is strong, and neither thread pulls out more easily than the other I'm assuming the tensions are reasonably well balanced.

So - any advice on the ideal point in the stroke to stop and pivot please - and is it different for different straight stitch vintage machines that don't have a "needle down" option which decides for you?

And does anyone else remember that online source that speaks about corners the same top-and-bottom being another indicator of good tension?

Thanks heaps... Megan