MB3 191a: Diapers, Safety Pins and Sewing on Shabbos (340:5-7)

Making a mark in a book with one's fingernail on Shabbos

Restitching an open seam is prohibited on Shabbos.

The shiur for the melacha of stitching מדאורייתא on Shabbos is 2 stitches plus a knot or 3 stitches even without a knot.

Using safety pins or staplers on Shabbos.

Using a diaper's adhesive closures on Shabbos.

Lacing shoes on Shabbos is not considered stitching.