Originally Posted by
coloradosky
... Singer 27-4 treadle ... the top thread looked beautiful however when looking on the underside the top thread just hung in huge loops...
It sounds possible that your machine has a manual upper tension release, and the upper thread is not getting set into the tension properly when being threaded at times, or the upper thread is somehow getting out of the tension disks in the upper tension during use. See if there’s a problem getting and keeping the upper thread in the tension disks.
CD in Oklahoma