Can you craft watches in Terraria mobile?
Watches on the Terraria wiki
As noted on this page, watches are only available in desktop and console versions of Terraria. In addition, the update history lists the fact that watches in the mobile version cannot be crafted.
Since the only legitimate way to obtain watches is via crafting, you cannot currently obtain watches in the mobile version of Terraria.
Watches are not craftable on Terraria Mobile.