brass tacks, n. — Green’s Dictionary of Slang

brass tacks n.

(orig. US) the facts, as in the central issues or heart of a matter, and as such almost SE; also attrib.

[1922		S. Lewis Babbitt (1974) 152: His lecture on ‘Brass Tacks Facts on Real Estate’].
1924		Philadelphia Inquirer (PA) Sun. Morn. 27 June 6/8: [advert] For brass tact fact address Dept. 65.
1949		Western Dly Press 12 Jan. 2/3: It is simply Cockney rhyming slang — brass tacks — facts.
1960		J. Franklyn Dict. of Rhy. Sl.
1969		S.T. Kendall Up the Frog.
2002		B. Kirkpatrick Wicked Cockney Rhy. Sl.

In phrases

get down to brass tacks (v.) (also come (down) to brass tacks, get/come down to tacks, get to brass tacks)

to approach the facts, to deal with the real heart of the matter.

1866		Brighton Gaz. 9 Aug. 8/1: ‘Come down with the brass tacks’ closed the entertainment.
1867		Sunbury American (PA) 12 Jan. 2/4: The Galveston Bulletin says that Texas must ‘come down to brass tacks’ and accept the constitutional amendment.
1868		Wyandot Pioneer (Upper Sandusky, OH) 14 May 4/3: Bring things right down to brass tacks in all the affairs of this life and the millenium is not far away.
1898		Wells Jrnl 16 June 3/3: When it comes right down to brass tacks we can whip the whole the rest of the world combined at the drop of a hat.
1903		A.H. Lewis Boss 119: Let’s cut out th’ polite prelim’naries [...] an’ come down to tacks. How much stuff do you feel like blowin’ in?
1907		Goodwin’s Wkly (Slat Lake City, UT) 1 June 5/1: When it gets down to brass tacks the Herald is just as subservient to the church.
1911		Centralia (Wash.) Chronicle 25 Jan. 4/3: They will be ‘getting down to brass tacks’ (if one will pardon a slang phrase in discussing so serious a question.).
1911		H. Quick Yellowstone Nights xi 288: When you come down to brass nails [DA].
1914		S. Lewis Our Mr Wrenn (1936) 52: I don’t much believe in all them highbrow sermons that don’t come down to brass tacks.
1915		S. Ford Shorty McCabe on the Job 139: Well, cut out the frills and let’s get down to brass tacks.
1922		S. Lewis Babbitt (1974) 18: They don’t [...] ’tend to business and get down to brass tacks.
1932		V.F. Nelson Prison Days and Nights 36: That’s about all anybody can do for a guy when he’s in the can, anyhow, when you come right down to brass tacks.
1936		R. Chandler ‘Guns At Cyrano’s’ in Red Wind (1946) 235: Take a look at that. Then we can get down to tacks.
1937		A. Christie Murder in the Mews (1954) 181: When it comes to brass tacks the dressed-up trollops win hands down!
1941		G. Kersh They Die with Their Boots Clean 142: War always was war, and when it came down to brass tacks, it was the same as it is now.
1943		‘Henry Green’ Caught (2001) 165: Yet when it comes down to brass tacks, when somebody takes a fancy to drill him, he’s not even on the premises.
1949		H. Miller Sexus (1969) 327: Come on, let’s get down to brass tacks.
1951		Cusack & James Come in Spinner (1960) 26: If you come down to brass tacks, Molesworth practically runs the pub.
1955		P. Rabe Benny Muscles In (2004) 185: Sit down, Pendleton, and let’s get down to brass tacks.
1960		Wodehouse Jeeves in the Offing 152: I am as intrepid as a lion and only too anxious to get down to brass tacks.
1965		Kerouac letter 23 Dec. in Charters II (1999) 415: This time we’ll get to brass tacks.
1970		‘Troy Conway’ Cunning Linguist (1973) 14: So I got dressed in a hurry and got down to brass tacks.
1971		Wodehouse Much Obliged, Jeeves 67: You didn’t make a speech of any sort before getting down to brass tacks?
1978		F. Norman Dead Butler Caper 51: I ordered more whisky and got down to brass tacks.
1989		Philadelphia Inquirer (PA) 6 Dec. 18-NE/1: No mincing words here, we’ll get down to brass tacks.
1993		Tarantino & Avery Pulp Fiction [film script] 127: Let’s get down to brass tacks.
2001		Irish Indep. 17 July 8/3: The Cabinet has yet to get down to brass tacks on the question.
2017		Houston Herald (MO) 2 Nov. A007/1: Down to brass tacks [...] meaning getting down to basics or essentials.