To get Holt blossom for the Purity Potion I have to make a Refined Sickle, to craft that I need to build a Refined workbench, to build that I need Shaft and Wire. But I can only make ingots in the Simple Smelter and to build a Refined Smelter I also need Shaft and Wire. So I'm stuck.
The simple smelter can make glass, ingot, shaft, and wire. If the recipe does not show in the simple smelter you must go to the Refinement tab of the Progression menu and unlock these recipes using tier 1 essence.