If, for some reason, being able to still combine tools without the grindstone is not considered a bug (or at least one that will be fixed), I would obviously like to figure out how to myself.

I have discovered that by replacing certain recipe files with a blank one, only that recipe fails to load and is uncraftable ingame, while the rest of the pack continues to work fine; The exact behavior that I want.

I have added a blank file called "crafting_special_repairitem" into the recipes folder of my pack, yet tools can still be combined as normal ingame. In the debug log, it even says failed to load recipe, but again, tools can still be combined.