If you use regular thread, doubling the thread is standard procedure, AFAIK. For big coat buttons, I actually quadruple the thread, that is, double it and then stick the doubled end through the eye of the needle, then tie it off, leaving me with a four-thread strand to work with. If you want to avoid this, you can get thicker waxed thread to do it properly, but I'm not sure what kind exactly.
The thread you are referring to is called Cotton GlacÃ©. Usually #24. Rabbi Mark
Of course, Mr. Kabbaz is shuddering and seriously considering tracking me down to thrash me with a single thread
Unless using silk as on a suit, glacÃ© button thread should always be doubled. You can come out of hiding now, Rabbi. bengal-stripe
That's how I know a "crow's foot on buttons: Button has 4 holes: 1 2 3 4 stitch from hole 1 to 4, then from hole 3 to 4 and hole 2 to4. So you have three rows of stitching, all ending up in hole 4, which will form the shape of a petal (or a crow's foot).
You're quacked. That's a duck. Tiger's foot is a crow's foot. Now how, you may ask, can a Tiger's foot be a crow's foot ... losing it ... losing it. Moving rapidly on (before Bengal decides to come after me
), I tried to take photos today of Monika sewing a button. If they come out clearly, I'll post them.