It has been covered seversl times. Rather than searching I will repeat the gist here. Stroj is the default neutral word. Mašina is a colloquial word that is also (even more colloquially) used to denote a train locomotive (train engine) or some road vehicles (esp. motorcycles).
I need help clarifying the difference between "Ten, Ta, To" and "Ty, Ti, Ta" because even my wife (who is Czech) is not able to describe the difference... For instance, for this phrase I wrote "These machines..." But I got corrected that it should be "Those machines..." But my wife says that "Ty" can be used to say "these" also (as for things that are close to the person who is speaking)
"Ten" (and its variants, "ta", "to", etc.) is a demonstrative pronoun with an unspecified distance. It usually corresponds to English "that", sometimes to English "the" (when we want to stress the definiteness), occasionally even to English "this".
When we want to specify the distance, we use two other sets of demostrative pronouns:
If the object is far from the speaker, we use "tamten" ("tamta", "tamto" etc.), which corresponds to "that", but more accurately to "that ... over there".
If we want to stress that the object is close to the speaker, we use "tento" ("tato", "toto"...), which corresponds well to "this". The more colloquial version is "tenhle" ("tahle" ...).
So "Ten, ta, to..." normally doesn't say anything about the distance (this x that). When your wife said that "ty" could be used for "things that are close to the speaker" - yes, but in that case it would translate as "the" in English rather than "these". I hope this makes it more clear.
They are homonyms like the words "lie" (to recline / to tell falsehood).
1) personal pronoun "ty" - informal/singular "you" (thou)
2) demonstrative pronoun "ten" (that) - its plural feminine form happens to be "ty" without any connection to the personal pronoun
(neither is an adjective)