[Regarding a piece of] tamei iron that one mixed with [a piece of] tahor iron, if the majority is from the tamei [source, the newly formed utensil] is tamei. And if the majority is from the tahor [source, the utensil] is tahor. [If it is] half and half, it is tamei. And the same applies [to a utensil made] from chalama and cattle dung. [A door bolt with] a knob is tamei. But [if it is] plated, it is tahor. A pin tumbler and a bolt are tamei. And [regarding] a [door bolt with a] knob, R’ Yehoshua says: [One may only] drag it from this door and hang it on another one on the Sabbath. R’ Tarfon says: It is like all [other] utensils, and may be carried within a courtyard.

The bit of a bridle is tamei. But the cheek-pieces [are] tahor. R’ Eliezer rules the cheek-pieces tamei. And the Sages say: Nothing is tamei except the bit. But when they are joined, everything is tamei.

A whorl [made] of metal, R’ Akiva rules it tamei, but the Sages rule it tahor. And a plated [whorl] is tahor. A spindle, a distaff, a rod, a symponia, and a flute, [if they are made] of metal, they are tamei. But [if they are] plated, they are tahor. [However,] if a symponia has a receptacle for [valves resembling] wings, it is tamei in either case.

A horn that is curved is tamei. But a straight [horn] is tahor. If its mouthpiece was of metal, it is tamei. [Regarding] its bell, R’ Tarfon rules it tamei, but the Sages rule it tahor. And when they are joined together, everything is tamei. Similarly, the branches of a candelabra are tahor. But the perach and the base [of the candelabra] are tamei. And when they are joined together, everything is tamei.