The thing that irks me most is that I got the word "frizzen" from
"The History of English in it Own Words" by Craig M. Carver, p 187,
in a discussion of "skinflint". Too bad he didn't research the word
before he used it.
The correct terms seem to be part of the problem. The "cock"
holds the flint, and strikes the "hammer". This is hardly the ordinary
sense of "hammer" which is usually in motion striking something else.

A case of "hitting der hammer mit der nail".