I have had these pins for a long time, like over twenty years, and have lost quite a few over time, so I have been keeping an eye out for suitable replacements. The finest pins I can find at local sewing/crafts stores are about 0.7 mm in diameter. They feel like tree trunks next to the finer pins! Fortunately, my quest for really fine pins ended with the recent discovery of “Clover’s Patchwork Pins, #2507“.
They’re 0.4mm in diameter and 36mm long. They’re $8.25 for 100, plus shipping of course. I used them in making my denim pants. I like ’em! Since the shaft is so fine, they glide through multiple layers of denim with ease. Of course, since they’re quite fine, they’re a bit more delicate than the stouter pins and can bend more easily. All the same, the pins’ steel is springy, so they stand up to a bit of bending without being permanently deformed.
As a bonus, the pin head is glass, so they can withstand heat from an iron, if necessary.