@@ -1,13 +1,26 @@
 -- the math basically needs to be rewritten from scratch by someone who isn't
 -- dyscalculic but 
+local L = sorcery.lib
+local M = function(i) return sorcery.itemclass.get(i, 'material') end
 sorcery.lathe = {
 	techs = {
 		cut = {dmg = true};
-		intaglio = {consume = true};
+		intaglio = {
+			consume = true;
+			toolpred = function(tool)
+				if minetest.get_item_group(tool, 'sorcery_powder') == 0 then return false end
+				local cl = sorcery.itemclass.get(tool, 'metal')
+				return cl.data.hardness >= 3
+			end;
+			validate = function(tool, wkpc)
+				return M(tool).data.hardness >= M(wkpc).data.hardness
+			end;
+		};
 	};
 	tools = {
-		sword = 'cut', knife = 'cut', blade = 'cut';
+		['group:sword'] = 'cut', ['group:knife'] = 'cut', ['group:blade'] = 'cut';
+		['group:sorcery_intaglio_powder'] = 'intaglio';
 	};
 	recipes = {};
 	register = function(def)
 		local recipes = sorcery.lathe.recipes
@@ -21,9 +34,9 @@
 	register_metal = function(def)
 		local parts = sorcery.data.metals[def.metal].parts
 		local out = ItemStack(def.output)
 		for _, ty in pairs {'ingot', 'block', 'fragment'} do
-			local pt = parts[ty] 
+			local pt = parts[ty]
 			local ptc = sorcery.itemclass.get(pt, 'metal')
 			if ptc and ptc.value then
 				if def.mass <= ptc.value then
 					local mass
@@ -58,13 +71,25 @@
 		end
 	end;
 	tooltech = function(tool)
 		if type(tool) ~= 'string' then tool = tool:get_name() end
-		for g,t in pairs(sorcery.lathe.tools) do
-			if minetest.get_item_group(tool, g) ~= 0 then
+		local ts = sorcery.lathe.tools
+		if ts[tool] then return ts[tool] end
+
+		for id,t in pairs(ts) do
+			local q, g = L.str.beginswith(id, 'group:')
+			if q and minetest.get_item_group(tool, g) ~= 0 then
 				return t
 			end
 		end
+
+		for tech, t in pairs(sorcery.lathe.techs) do
+			if t.toolpred then
+				if t.toolpred(tool) then return tech end
+			end
+		end
+
+		return nil
 	end;
 }
 
 local R = sorcery.lathe.recipes
@@ -219,27 +244,38 @@
 		local inv = minetest.get_meta(pos):get_inventory()
 		if list == 'tool' then
 			local s_wkpc = inv:get_stack('workpiece', 1)
 			local tech = sorcery.lathe.tooltech(stack)
+			if not tech then return 0 end
+			local vdtr = sorcery.lathe.techs[tech].validate
 			if tech and (s_wkpc:is_empty()
-			or (R[s_wkpc:get_name()]       ~= nil and
-				R[s_wkpc:get_name()][tech] ~= nil))
+						or (R[s_wkpc:get_name()]       ~= nil and
+							R[s_wkpc:get_name()][tech] ~= nil and
+							(vdtr == nil or vdtr(stack,s_wkpc) )))
 					then return stack:get_count() end
 			for g,v in pairs(s_wkpc:get_definition().groups) do
 				local gs = R['group:'..g..'='..tostring(v)] 
 				local gg = R['group:'..g] 
 
 				if (gs and gs[tech])
 				or (gg and gg[tech]) then
-					return stack:get_count()
+					if vdtr == nil or vdtr(stack, s_wkpc) then
+						return stack:get_count()
+					end
 				end
 			end
 		elseif list == 'workpiece' then
 			local s_tool = inv:get_stack('tool', 1)
 			if R[stack:get_name()] then
-				if s_tool:is_empty()
-				or R[stack:get_name()][sorcery.lathe.tooltech(s_tool)]
-					then return stack:get_count() end
+				if s_tool:is_empty() then return stack:get_count() end
+
+				local tech = sorcery.lathe.tooltech(s_tool)
+				if tech and R[stack:get_name()][tech] then
+					local vdtr = sorcery.lathe.techs[tech].validate
+					if vdtr == nil or vdtr(s_tool, stack) then
+						return stack:get_count()
+					end
+				end
 			end
 		end
 
 		return 0