Quotation על שבת 96:7

If a stick was used as a handle for a hatchet, it is regarded as connected for uncleanness at the time of use. A yarn winder is regarded as connected for uncleanness at the time of its use. If it was fixed to a pole it is susceptible to uncleanness, but it is not considered connected to it. If the pole itself was converted into a yarn winder, only that part which is needed for use is susceptible to uncleanness. A seat that was fixed to the pole is susceptible to uncleanness, but the latter is not regarded as connected to it. If the pole itself was turned into a seat, only the place of the seat is susceptible to uncleanness. A seat that was fixed to the beam of an olive-press is susceptible to uncleanness, but it is not connected to it. If the end of a beam was turned into a seat it remains clean, because people would tell him, "Get up and let us do our work."