Etymologies and relationship between the characters 錘, 槌, 鎚, and 椎
From my answer to this question If you can use Chinese nouns as verbs, or vice versa

Typically, a word was either coined for a noun or verb first, and then its meaning extended to other word type for convenience's sake.
For example, It is possible that when people invented drill, they called it '鑽' (n); later when they needed a word to describe the action of 'to drill' , it is very convenience to add the meaning to the existing noun and make '鑽' both noun and verb.
Or it is the other way around, people called the action of 'to burrow' as '鑽'(v); when 'drill' was invented, they just use the verb '鑽' to name it, because a drill 'burrow' into things.
So, when a noun is closely associated with an unique action (verb), it would be used as a verb eventually; similarly when a verb is closely associated with an object (noun), it would be used as a noun eventually


Either 椎 was coined as a verb for &quot;to strike&quot; and gained the meaning of the noun for &quot;hammer&quot; later; or 椎 was coined as a noun for &quot;hammer&quot; and was given the meaning of the verb &quot;strike&quot; later.  Because the main function of a hammer is 'to strike things'

It is most likely that 錘 original meant something else, and later became a variant of 椎 because they sounded alike

槌 is defined as hammer; mallet; gavel; pestle. It should be the original form of the character for 'hammer'  when hammer was made of wood

鎚 is not listed in the dictionary, it seems to be a modern variant of 槌 when metal hammer appeared