I figured out how to craft it also and made one. 
It is a custom tinker craft.
You have to be wearing two of Uisenech's Alchemy Garb in order to use the grinder once you create one.
You can make the following with it:
- Alchemy Gold Powder -Couldn't find info on this one
- Powder of Pyrite - Changes Alchemy Garb into Leprechaun Gold. Lower end powder will give only a little gold but higher end powder can return over 50% of the Leprechaun gold invested in the gear.
- Powder of Golden Goblin - Recharges the Ring of the Goblin King
- Powder of Doolittle Protection - Can combine Doolittle Potions for longer duratio
On the wiki it does say "There is a bonus difference between a Powder Grinder and an Exceptional Powder Grinder. The exceptional tools also give crafting bonuses." There are other powders I would like to create but not listed in the crafting menu. I may try to get an exceptional tool to see if by chance it had the other powders unless someone knows for sure if those powders are no longer craftable.
I am specifically looking for Powder of Invidia - Hit Dispel. I know you can buy it from stone or find it in loot.