A Language Log post by Mark Liberman introduces me to a very interesting word which he spells “dykes,” meaning ‘diagonal cutting pliers’ (“as a tool term, dykes is always plural, like scissors“). Now, googling “diagonal cutting pliers, dykes” (without the quotes) gets me 367 hits, while changing “dykes” to “dikes” almost doubles the number, to 706, so there may be a slight preference for the latter spelling, but both the totals and the difference between them are small enough that it’s impossible to tell. One wants, therefore, to consult a dictionary—but as Mark says, the word “isn’t in the AHD, M-W Unabridged, the OED, or Encarta.”
I think this is really strange. As far as I know, dykes is the standard American term for this ubiquitous and useful tool. In my experience as a child working on bicycles and later cars with my friends, as a mechanic in the army, and hanging around electronics technicians at Bell Labs, “dykes” was as common as a term as hacksaw or chisel. I mean, what else would you call them?
It is indeed strange; I don’t recall previously seeing a normal word of long standing, even one of limited circulation, that was not in any dictionary; that snub is usually reserved for recent slang terms. For what it’s worth, this site says “The diagonal cutting pliers, commonly called ‘diagonals’ or ‘dikes’…”, which suggests a shortening of diagonal and would seem to support the spelling with i. But one JAX in this discussion says “Dykes was the surname of the guy who invented the best of its time wire cutters. ‘side Dykes’ was the name of the later diagonal model.” Until the lexicographers take note of this neglected lexical item and settle on an etymology, you can pick whichever spelling looks right to you and no one can prove you wrong.