Q. If thirty days is the time for repayment for borrowing money. If I lend an object such a tool or a book is the term also 30 days?

A. Shulchan Aruch (C.M. 73: 1) rules that the thirty day period for repayment applies only to money which is given to spend or invest and not to have exactly the same coins, bills or checks returned. However, when it comes to lending objects the thirty day rule does not apply. Mishna Berura (307: 42) rules accordingly. Miktzoa BaTorah (73: 3) depend the rule of thirty days only on the language used, which customarily is in Hebrew “halva’a” for currency loans, while “shailah” is wont for lending objects. According to his opinion if the expression halva’a was used for objects the thirty day rule will take effect and it will not even for currency if the term “shaila” was mentioned. However, in English where there is no grammatical distinction for these two actions, it all depends on the case and the local custom. (See also Pischei Mishpat ibid. 2)
Horav Shlomo Miller’s Shlit”a opinion is that in regards to borrowing objects, obviously some such a car, some tools or a pen are to be returned immediately after finishing their use, while on books that one reads from cover to cover, the lending period is longer.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a