Blood Craft (3.5e Feat)
From D&D Wiki
Blood Craft [General]
You learn to infuse items with your blood.
Prerequisite: blood component ability, any two item creation feats
Benefit: When crafting magic items, you may choose to sacrifice a number of hit points equal to your Constitution modifier, you now gain blood crafting points equal to twice that amount. Blood crafting points can be used instead of experience points when crafting magical items or casting spells with an experience point component.
Special: A character may only use this feat once per item crafted or spell cast, left over points don't carry over to other items or spells. For every 5 hit points sacrificed, the character takes 1 point of Constitution damage.