diff --git a/mods/ITEMS/mcl_smithing_table/init.lua b/mods/ITEMS/mcl_smithing_table/init.lua
index 1794f8791..996dcf8a9 100755
--- a/mods/ITEMS/mcl_smithing_table/init.lua
+++ b/mods/ITEMS/mcl_smithing_table/init.lua
@@ -167,16 +167,19 @@ minetest.register_node("mcl_smithing_table:table", {
 	end,
 
 	allow_metadata_inventory_put = function(pos, listname, index, stack, player)
+		local stackname = stack:get_name()
+		local def = stack:get_definition()
 		if 			
 					listname == "upgrade_item"  
-			and	 	string.find(stack:get_name(),"mcl_armor:") -- allow any armor piece to go in (in case the player wants to trim them)
-			and not mcl_armor.trims.blacklisted[stack:get_name()]
+			and	 	def._mcl_armor_element -- allow any armor piece to go in (in case the player wants to trim them)
+			and not mcl_armor.trims.blacklisted[stackname]
+			or 		def._mcl_upgradable -- for diamond tools
 
 			or		listname == "mineral" 
-			and		mcl_smithing_table.is_smithing_mineral(stack:get_name())
+			and		mcl_smithing_table.is_smithing_mineral(stackname)
 
 			or 		listname == "template"
-			and		string.find(stack:get_name(),"mcl_armor") 
+			and		string.find(stackname, "mcl_armor") 
 		then
 			return stack:get_count()
 		end