When building all the Refining Stations in V Rising, it seems that you need Whetstones to craft them. To build the Grinder, you need four Whetstones, but the recipe to craft them in the Furnace is locked.
V Rising Whetstone Complete Guide
Getting Whetstones to build the Grinder isn’t hard. What’s more challenging, however, is crafting them. There’s an easy way to find Whetstones while exploring the map to craft the Grinder, and craft the Whetstones themselves later.
The quickest way to get Whetstones in V Rising is to look for Bandit Encampments and Armories on the map that have Whetstones. As you walk around the world, you will see areas highlighted in yellow. Hover over the area and the Important Resources will tell you if you can find Whetstones in that area.
That way, you don't have to travel all the way to a random Bandit Camp if it doesn't drop exactly what you're looking for. The camp doesn't have to be discovered to reveal that information; you just have to walk close to it.
