Old general stores sold just about everything a family could need, including fabric. Embedded in the counter were small brass nails three feet apart, which were used to measure yards of material, which usually came in bolts of nine yards. If you needed only a few yards of material, you would "get down to brass tacks" and buy the desired amount. If, however, you needed a large quantity of fabric, then you would just say give me "the whole nine yards."

(just something I read)