Varnias Tybalt said:
Micro-etched incantations and purity seals seem to be enough to make most weapons holy. I don't see why it couldn't be done to Lathe blades during the forging process. Just get a Cleric to assist the Techpriests and let them go to town with it.
I can't imagine the Techpriests allowing a Cleric into the Lathes for that purpose.