What are the steps to go from pig tails to cloth bags? The wiki says the process plants/thresher skill is used to turn the pig tails into thread. I used the spin thread task, and my dwarf that has plant processor enabled has never gone and done it.
The step-by-step guide to turning pig-tails into useable cloth is as follows:
Grow pig-tails, or order your herbalists to scrounge the caverns for 'naturally grown' pig-tails.
At a Farmer's Workshop (b-w-w), order a dwarf to process plants, turning the raw plant into usable plant threads. This task requires the "Thresher" labor
At a Loom (b-w-o), order a dwarf to weave cloth (plant thread). This task requires the "Weaving" labor.
At a Clothier's Workshop (b-w-k), finally you can order a dwarf (with the clothesmaking labor) to make cloth bags. (Select cloth, rather than silk or yarn, and then select bag, which is either 'n' or 'b').