On Tue, 11 Aug 2015 21:29:13 +0100, no_spam wrote:

OK chaps and honourary chaps, here's a question about DIY sewing. SWMBO
is trying to sew buttonholes using a buttonhole attachment on a Singer
Talent sewing maching. The thing goes through the process of zigzag
stitching down one side and back up the other but the zigs (or zags?)
are more widely spaced on one side than t'other. I can't find a user
adjustment anywhere so am wondering whether it's an internal set-up
issue or a technique issue. Are there any sewing machin experts out
there?

The fabric is thicker on one side (near the edge?) and feeding at a
different speed?

Also check bobbin tension and feed tension are the same (although I can't
quite see why that would affect it).