Mishnayos Shabbos Perek 17 Mishnah 4

מסר גדול - a large saw that we saw boards.

ויתד של מחרישה – a large utensil made like a knife with which they make a incision of a turn of the plough/furrow’s length and they are strict with him and designated for them a place that is not worthy for any other labor.

כל הכלים ניטלים לצורך ושלא לצורך – this is how it should be understood: All the utensils whose labor is for permitted things such as plates and cups which are removed [on the Sabbath] for the necessity of its own body as well as for the necessity of the place of the utensil, as well as that which is not necessary, even if he doesn’t need the implement nor the place of the utensil, other than to carry it on account of the shade or that thieves should not steal it, it is permitted with a utensil that whose labor is something permitted. But a utensil that is used for some kind of prohibited labor, such as mortars and millstone and similar things for its own necessity and for the needs of its place, it is permitted, but from the sun to the shade or because of thieves, it is prohibited.

רבי נחמיה אומר אין ניטלין אלא לצורך – It is explained in the Talmud (Talmud Shabbat 124b) for the needs of its unique use alone but not for the needs of something else, even for its own needs, such as a knife to cut with alone, it is permitted, and not to support with it the bowl. But the Halakha is not according to Rabbi Nehemiah.