D&D Crafting Mechanics

PLAYER CRAFTING

1. Artisan Tools must be available and characters must be proficient. The DM may rule a workshop or laboratory is also needed. Tools are abstracted as "smithing tools," etc. A laboratory or workshop are likewise abstracted as "smithing workshop," etc.

2. Materials are required to craft. Assume that the cost of materials needed is equal to half the cost of the item being crafted. Materials are abstracted as "smithing materials," etc. The DM and the setting determine availability of materials.

3. Time. Crafting time is abstracted and simplified. For simplicity, crafting time is based on item rarity, not artisan skill or material cost. Rarity may vary based on the setting. The table for Crafting Time is:
Common Items    1 Workday
Uncommon Items    2 Workdays
Rare Items    1 Workweek
Very Rare Items    2 Workweeks
Legendary Items    4 Workweeks

The DM may rule a particular item is atypically simple or complex, in which case the crafting time is either halved or doubled. A workday is 8 hours. Characters must complete each workday or the day is not counted and a workday worth of materials is wasted. Crafting time is divided by the number of skilled artisans working together on an item if it's reasonable for multiple artisans to work on the same thing, and they must be in the same place at the same time. DMs determine if it is possible to improve or refine an existing item and they may halve crafting time and / or material cost. Unique items should be based on similar items.

4. Knowledge. Characters must know how to craft the item. The DMs may assume characters proficient with tools know how to craft common items. Before attempting to craft, players roll an intelligence check and add their tool proficiency bonus to determine if their character knows how to create it. The DCs are:
10    Common Items
15    Uncommon Items
20    Rare Items
25    Very Rare Items
30    Legendary Items

If players succeed, the DM may assume all attempts to craft that item are successful. If player fails the check, it means the character does not know how to create the item. Characters may seek instruction from a teacher or a manual. A teacher automatically teaches a character in one day. Characters can study a manual for one day and repeat the Intelligence check. If characters do not have access to instruction, they may attempt to create the item and work it out by trial and error. To do this, they must spend all required time and materials, the roll the intelligence check with disadvantage to determine success of failure of item creation. If the character succeeds, they also learn how to craft the item. If they fail, the materials are wasted. In the case of failure, the DM determines whether the character has made a useless item or an inferior quality item, whichever is more reasonable.