Player's Handbook lists some rules about downtime activities, including crafting (p. 187), as does Dungeon Master's Guide (p. 127). In both resources, downtime activities are defined as activities characters can participate in between adventures. What about during adventures?
Say my character is proficient in carpenter's tools. In 10 days, he can craft a longbow for 25 gp (market price 50 gp). According to the rules (please no "Ask your DM" answers), can he work on crafting a longbow while traveling during an adventure?
Considerations
- Can certain crafting activities be performed while traveling? This obviously depends on what kind of crafting is being performed—I don't see how a blacksmith could bring his forge and anvil with him on an adventure. However, I don't know why it would be so difficult for a painter, a leatherworker, or a jeweler to craft an item while traveling. Even a carpenter or weaver could conceivably craft while traveling if their project and the tools needed to craft it are portable enough. (Maybe not a chair, but why not a wooden bowl or a shortbow?)
- If the party is on the road and camping but not resting (not engaging in combat), could some of this extra time be spent crafting? The rules regarding traveling "assumes that characters travel for 8 hours in day" (PHB, p. 181). If a long rest takes 8 hours, that leaves 8 more hours in the day for other activities.
- Could crafting be performed during part of a long rest? As previously mentioned, a long rest takes 8 hours; two of those hours can be used to perform "light activities" (PHB, p. 186). While some crafting activities may not be considered light work (pounding heated metal on an anvil into a sword), one could argue that other crafting activities (painting, whittling a length of wood, weaving a shirt or blanket, etc.) is light work. Furthermore, since [an elf's long rest is over after 4 hours], one could further argue that an elven crafter could craft for 4 hours while his or her traveling companions finish their long rests.
Again, I'm looking for RAW answers—I consider that "ask your DM" is always the given answer in the absence of RAW rules. Thanks!