Originally Posted by
your_comforting_company
Ted, my hand spindle is mullein and hearth is black willow. I like the softer spindle for hand drilling and ember. Bow drill I use yucca for the spindle and it is only marginally softer than mullein.
One tip is that you should be able to dent the wood with your fingernail. dents easily is good for spindle, and dents a little less good for hearth.
At least that's what works for me, I've read about folks using lots of different things so experimenting will tell you best what works, but the fingernail trick will help you determine suitable materials.