For the longest time since (mid-1980s) I have wondered what ‘oversew’ meant when hiding tails at the end of a tatting project. I came across it in my Anchor and Coats books. Tried my own methods (including overcast stitch as in embroidery) but none worked out – knotting was the only way I knew and continued with it despite the 'ugliness'.
Two decades later, on the net, I asked around,
to no avail, but I switched to whip stitch some years ago. Until a few months back when Jean Inglis used
the term in her FB post! At my request, she explained and also uploaded a WIP
pic. It got me thinking and I obviously had to try it out to compare and
contrast with other sewing methods of hiding ends/tails as compiled here -. https://tipsaroundthehome.blogspot.com/2016/11/beginning-or-ending.html
In my current study, I found two main methods that are commonly used to sew in the ends. Please excuse my shoddy samplers below (the sewing thread/tail should not be visible once it is pulled tight). I have used a contrasting blue thread as tails or ends for the purpose of clarity.
The first is what I will now refer to as OVERSEW.
Here, we sew the tail Under the cap or waist band of the double stitch, and weave between the legs of the ds - under and over the half-stitches. Hence a 10 ds count segment will give you 10 stitches front and behind. This method is diagrammed clearly by Jennifer Williams - https://www.cariad-tatting.com/techniques.Jean Inglis' Mom taught her to tat in 1980 and to sew in her ends as above. She used the term 'oversew'. She unravels the tail and uses the thinner thread to sew and hide, thus leaving a tinier footprint. But look closely, and you realise it is actually the whip stitch! Yet, this unraveling of thread can be used for the oversew methods described above, too.
In conclusion, I'd say traditionally 'oversew' would simply have meant to sew in the tails whether you wove the tail under or over the caps; between double or half-stitches. However, if we wish to fine tune it, we can differentiate oversew from whip stitch as explained above.
Feel free to share your own thoughts and experience; no need to hide them!
Many thanks to all mentioned above, and those not mentioned, who constantly help us improve our knowledge, understanding, and skills.