Unknown.[1] Earliest attestation in 1863 US, specifically Texas.[1] One theory is that it comes from the brasstacks in the counter of a hardware store or draper’s shop used to measure cloth in precise units (rather than holding one end to the nose and stretching out the arm to approximately one yard). Another possibility is the 19th-century American practice of using brass tacks to spell out the initials of the deceased on the top of their coffin. Yet another theory is that the phrase arose from the practice of adorning one’s gunstock with brass tacks, as was common in the early American West. Brass was frequently used because it could be easily polished and didn’t rust. According to author Stanley Vestal, “Brass tacks hammered into the stock of the rifle marked the tally of the mountain man’s victims. Brass tacks.”[2]
You must be Jules, which would make you Vincent. Let's get down to brass tacks, gentlemen. If I was informed correctly, the clock is ticking. Is that right, Jimmie?