Why a monkey wrench?

I was pondering the other day, why is a monkey wrench called a monkey wrench in common parlance? And is that the ‘proper’ name, or slang? And are there different names for this piece of kit in other countries? My husband calls this tool a pipe wrench. I have heard someone call it an adjustable spanner. I have the niggling feeling that I have also heard it called an adjustable crescent. The Aussies seem to call it a shifter. 

After a bit of digging, there was patent as a ‘screw adjust wrench’ first registered 190-odd years ago by one Solyman Merrick of - the Simpson’s town? - Springfield Massachusetts, on 17 August, 1835 (DATAMP, 2023a). And note the interesting spelling. I wonder how well educated Mr Merrick – or his Dad – was, in order to create such an unexpected and novel hash of Solomon. Ah, well.

Six years later, a Mr Coes of Worcester Massachusetts came up some interesting modifications, registering a one-handed wrench patent on 16 April 1941, for “Loring Coes’ Screw Wrench” (DATAMP, 2023b). A quick check of Google Maps shows that Merrick and Coes lived roughly 80km apart: could one have pinched the idea from the other? There was definitely some animosity, as Solyman Merrick and Loring Coes fought it out in the courts through the later 1800s trying to sort out just whom was infringing on whose patents.

But this was to no avail for poor Solyman, as Coes' patent appears to be the originator of all later tools now known colloquially as a ‘monkey’ wrench (DATAMP, 2023b; it could be the bad spelling wot did Solyman in, mind you). OK, so this is where the adjustable spanner tool was ‘born’, but why ‘monkey’?

A quick consult of the ‘shorter’ Oxford English Dictionary (1989) provides the following:

“monkey-wrench, a wrench or spanner having a movable jaw; also Tig., esp. in colloq. phr. to throw (or hurl) a monkey-wrench into the machinery, etc.; to act as an obstruction or hindrance; to ‘throw a spanner into the works’; hence as v. trans., to turn with a monkey-wrench” (p. 1006); followed by selected examples: “1858 Simmonds Dict. Trade, *Monkey-wrench. [...] 1920 Everybody's Mag. May 36/3 Don’t throw a monkey-wrench into the machinery! 1931 Daily Express 16 Oct. 1/2 Mr. Lloyd George hurled a monkey wrench last night into the creaking and decrepit machinery of Liberalism” (p. 1007).

So by 1920, a monkey wrench was a metaphor for industrial sabotage, and by 1931, had the same connotation in politics (and 'a spanner in the works' too, no doubt). But still no idea why ‘monkey’.

I looked up the OED's earliest mention, in Simmonds’ Dictionary of Trade, to find “MONKEY WRENCH, a spanner with a moveable jaw” (1958, p. 251). There is no further explanation. The term must have been in common enough use by 1858 to have appeared in a dictionary of trade terms: the Dictionary’s preface states its aim was to “define only the ordinary and popular names – English or foreign; and consequently an [item can] be sought under its common designation” (p. vi).

Being little further ahead, I then consulted the guru on all things words, Michael Quinion, at World Wide Words. Blast it: I should have done that first. Mr Quinion (2009) says that the first VERIFIED sighting of monkey wrench turns up in an amazing inventory of the railways of the UK. Found under “Orders to Enginemen and Firemen” (Whishaw, 1940, p. 210) as part of the inventory of the “Liverpool and Manchester Railway” this 665 page work “includes [an 1837] list of tools that must be kept in a locomotive cab” (Quinion, 2009) which reads as follows:

“3. Every engineman shall have with him at all times in his tender the following tools […] A complete set of screw-keys, one large and one small monkey wrench…” (Whishaw, 1940, p. 211).

As railways were a UK invention, then it seems likely that the monkey wrench is a UK-named tool. But wait, there’s more. Mr Quinion knows of an – as yet – UNVERIFIED sighting, “dated 1807 to a firm supplying ‘Screw plates, lathes, clock engines [...] monkey wrenches, taps’. The entry in the online Oxford English Dictionary includes this but with a question mark before the date which means that their editors have yet to verify it beyond doubt” (2009, citing Dane, 1973; Miller, 2018). This refers to one Richard Fleetwood, who produced in Parr, Rainford in 1807 "Screw plates, lathes, clock engines, stocks and dies, milling tools, monkey wrenches, taps" (Dane, 1973, p. 219), but Dane's source evidence - as far as I know - has not been verified by the OED enough to be included in the dictionary. We don't know what this looked like though.  

A screw wrench engraving dating from 1809 by one William Barlow, shown in the “Repertory of Arts, Manufactures, and Agriculture, 15(2), Plate III, Figures 10-12” may be an early example (Brown, 2015). There is no sign that this was called a monkey wrench, and it is two years after the unverified 'monkey wrench' in Dane (1973), but it is possibly one, so I have illustrated this post with it.

So. The monkey wrench was in print BEFORE Loring Coes registered his patent. While Mr Coes screw wrench may be called a monkey wrench, it is a conferred existing name, not the original, because we know in 1837, engineers on the Liverpool and Manchester Railway had to carry them, and it appears that a Mr Fleetwood was making them in 1807 (Dane 1973). 

But why 'monkey'? We are still not getting closer to why this name. Some suggest that a monkey wrench is called a monkey wrench because the head looks like a monkey (Brown, 2015; Staten, 1996). Some think there was a bloke called "Moncky", "Monckey" or "Monk" in the mix (Miller, 2018; Staten, 1996). It would be interesting to know what an original monkey wrench actually looked like, but the book by Dane does not contain any plates, so we are no wiser. 

We know monkey wrenches have been about for a long time. It is probably a UK name into US usage and back into the UK. But we still don't know why it is called a monkey wrench. 

Sam

References:

Brown, P. J. (14 October 2015). Charles Monk, Monkey Wrenches and a "Monkey on a Stick" - a Gripping History and Etymology of "Monkey Wrench". https://esnpc.blogspot.com/2015/10/charles-monk-monkey-wrenches-and-monkey.html

Dane, E. S. (1973). Peter Stubs and the Lancashire Hand Tool Industry. John Sherratt & Sons Ltd.

DATAMP. (2023a). Patents for Solyman Merrick. Directory of American Tool and Machinery Parts. https://www.datamp.org/patents/search/xrefPerson.php?id=20137

DATAMP. (2023b). US Patent: 2,054: Method of Constructing Screw Wrenches Loring Coes Screw Wrench. Directory of American Tool and Machinery Parts. https://www.datamp.org/patents/search/displayPatent.php?number=2,054&type=

Miller, D. (2018). Chapter x: On Possibility; or, The Monkey Wrench. In G. Mitman, M. Armiero, & R. S. Emmett (Eds.) Future Remains: A Cabinet of Curiosities for the Anthropocene (143-148). University of Chicago Press.

Quinion, M. (24 October, 2009). Monkey wrench. https://www.worldwidewords.org/qa/qa-mon5.htm

Simmonds, P. J. (1958). A Dictionary of Trade Products, Commercial, Manufacturing, and Technical Terms. G. Routledge & Co.

Simpson, J. A., & Weiner, E. S. C. (Eds.) (1989). Oxford English Dictionary (2nd ed., Vol XI Look-Mouke). Clarendon Press.  

Staten, V. (1996). Did monkeys invent the monkey wrench?: Hardware stores and hardware stories. Simon & Schuster.

Whishaw, F. (1840). The Railways of Great Britain and Ireland: Practically described and illustrated. John Weale.

Wilton, D. (18 May 2021). monkey wrench / throw a monkey wrench into. https://www.wordorigins.org/big-list-entries/monkey-wrench