stone splitting machine vs stone splitter

stone splitting machine and stone splitter both are nouns.

Word	Noun	Adjective	Verb	Adverb
stone splitting machine	Yes	No	No	No
stone splitter	Yes	No	No	No

As nouns, stone splitting machine and stone splitter are synonyms defined as:

stone splitting machine and stone splitter: a machine for splitting natural stone including granite, marble, and sandstone.

stone splitting machine (noun)	stone splitter (noun)
a machine for splitting natural stone including granite, marble, and sandstone.	a machine for splitting natural stone including granite, marble, and sandstone.