[KevinJ]

Replicate (C) [1+]: This spell creates an exact copy of the subject. Given enough ST the caster could make a duplicate of any object. Unlike Image or Illusion, this is a lasting physical, though completely inanimate, duplicate of the original object.
Replicated objects have the same size, shape, weight, and appearance of the original. A Mage need not know the intricacies of smithing to make a duplicate sword of fine steel.
Compound objects like clocks will look like the original on the outside and the inside, but will not function unless each part is Replicated separately and then assembled. Intricate objects suffer the fame fate.
The ST cost is 1 ST per pound of the object. Normal Replicated objects only last for 1 hour. By spending twice the ST an object will last for 24 hours. By spending 10 times the ST the object will last for 1 year. By spending 100 times the ST the object will be permanent.

Yes, making a functioning clock would require A LOT of ST, as each individual piece of 1lb or less weight would require 1 ST to create.