Bone masks can be crafted at the orcish tribal gearcrafter.

This is really just a flavour change, since I presume that
bone masks can be crafted at other workshops as well. However
it feels right for orcs to turn the bones of their enemies into
terrifying masks they can wear.

Dwarf Fortress/raw/objects/entity_orcfort_taigaorc.txt

@@ -860,6 +860,7 @@ REACTION:SPORE_TREE_GLUE => if you want glue from cavern trees, you ned to add i
 [PERMITTED_REACTION:LAMELLAR_MASK_ORC]
 [PERMITTED_REACTION:LAMELLAR_CLOAK_ORC]
 [PERMITTED_REACTION:LAMELLAR_ROBE_ORC]
+[PERMITTED_REACTION:BONE_MASK_ORC]
 [PERMITTED_REACTION:TRIBAL_CLAWS_ORC]
 [PERMITTED_REACTION:TRIBAL_CLAWS2_ORC]
 [PERMITTED_REACTION:TRIBAL_CLAWS3_ORC]

Dwarf Fortress/raw/objects/reaction_orcfort.txt

@@ -277,6 +277,13 @@ YESSTORAGE[PRODUCT:100:10:BAR:NONE:CREATURE_MAT:ENGINEER_CRATE:SOAP]YESSTORAGE[P
    [PRODUCT:100:1:ARMOR:ITEM_ARMOR_ROBE:GET_MATERIAL_FROM_REAGENT:A:NONE]
    [SKILL:LEATHERWORK]
 
+[REACTION:BONE_MASK_ORC]
+[NAME:craft bone mask]
+[BUILDING:ORC_TRIBALGEAR:NONE]
+   [REAGENT:A:1:NONE:NONE:NONE:NONE][USE_BODY_COMPONENT][ANY_BONE_MATERIAL]
+   [PRODUCT:100:1:HELM:ITEM_HELM_MASK_ORC:GET_MATERIAL_FROM_REAGENT:A:NONE]
+   [SKILL:BONECARVE]
+
 [REACTION:TRIBAL_CLAWS_ORC]
 [NAME:handcrafted tribal ironbone claws]
 [BUILDING:ORC_TRIBALGEAR:CUSTOM_SHIFT_C]
@@ -6926,4 +6933,4 @@ YESSIMPLEWOOD[REAGENT:A:5:WOOD:NONE:PLANT_MAT:ROUGH:WOOD]
 	[PRODUCT:100:1:TOOL:ITEM_TOOL_WARMRAYSMOJO:INORGANIC:SILVER]
 	[PRODUCT:75:1:TOOL:ITEM_TOOL_HIBERNATEMOJO:INORGANIC:SILVER] 
 	[PRODUCT:25:1:SHIELD:ITEM_SHIELD_DREAMCATCHER:INORGANIC:REGENERATION_ENCHANT]
-	[AUTOMATIC]	
+	[AUTOMATIC]