When did Monkeys start making wrenches?

Why is the pipe wrench often called a monkey wrench?

From the Ferris State University Jim Crow Museum website…

Q: Did Jack Johnson invent the wrench?

A: Jack Johnson, the first Black heavyweight boxing champion, patented a wrench (U.S. patent #1,413,121) on April 18, 1922. His patent was not the first for a wrench. Solymon Merrick of Springfield, Massachusetts, patented the first wrench in 1835. Charles Moncky, a Baltimore mechanic, invented the monkey wrench around 1858. Moncky's wrench was named using a purposeful misspelling of his name.

There appear to be 2 common misconceptions based on faulty internet information.

Supposedly there is a racially based myth that the monkey wrench was named after Johnson. However, the name was in use at least 100 years before, and his name only appears tangentially to the topic.

…suggests that African-American boxer Jack Johnson invented the tool, and the racists of the time added the label “monkey” as a racial epithet. However, neither part of this story is strictly true. (1)

The other would seem to be a continuation of the “Moncky” hoax. (2)

…Another hoax suggests that a man named Charles Moncky invented the tool. Historians have found no record of a Charles Moncky living in the area at the time it is said, though researchers found multiple Charles Monks. However, none of the possible Charles Monks can be the inventor. All were children when the tool was invented or born after the term “monkey wrench” was already in circulation. (1)

And yet another inventor was credited with the invention…

The apparent inventor of the monkey wrench is Loring Coes, who invented the tool in 1840 in Worcester, Massachusetts. *That date is about 37 years after the earliest recorded use of the term “monkey wrench”, however we know that this time the name stuck to the tool Coes invented, as its design remained in production by various companies for the next 120 years. (1)

…so it appears the term was already in use to describe the “carriage wrench”.

I thought perhaps it came from the phrase “monkey around”, but I cannot find any use before 1889 on Ngrams.

And it appears that the “smooth lipped” carriage wrench was called a “monkey wrench” at least 37 years before the invention of the modern day toothed-lip pipe wrench. Even though Coes gets the credit for the name, it was in use long before.

So why was it originally called a “monkey wrench” ?

(1) Healthy Handy Man

(2) Wikipedia
(3) Images Wikipedia

Etymonline has an interesting suggestion on its possible origin::

Monkey was used in 19c. especially by sailors, as a modifier for various types of small equipment made for specific work (monkey-block, monkey-boat, monkey-spar, etc.), and the same notion probably is behind the name of the tool.

WWW has citations from early 19th century:

In 1973, E Surrey Dane published a book with the snappy title Peter Stubs and the Lancashire Hand Tool Industry, which includes a reference 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.

There’s then a gap until it turns up in Francis Whishaw’s The Railways of Great Britain and Ireland, dated 1840; , in which he quotes Orders to Enginemen and Firemen issued by the Liverpool and Manchester Railway, dated 1837; this includes a list of tools that must be kept in a locomotive cab, including “one large and one small monkey wrench”.

A wrench is called a key "Schlüssel" (viz. schließen, Schloss); French mont- appears in Montage (cp. to mount). Thus it may be a mont-key (the t is silent by the way; What's the french equivalent, mont-cleve?), and the other terms noted by etymonline following from reinterpretation as "monkey" in jest.

PS: On second thought, consider the machanism of the thing. I want to say it may use a pin hole mechanism to fix the height, thus making another connection to key, but I'd want to connect mount, as long as key is already explained to satisfaction. There are different mechanisms, a screw or, as depicted above. Looking longer at the mechanism, I could see how the head climbs up (cp cleve again, now for a mondegreen).