The most grinding of them all. Designed for attaching together parts that are already felted a bit such as repairing dismounted joints.
Always dry your design first then card the parts you´re about to join together to get loose fibers to show, add fine layers of Lumi in between and punch together – then continue with felting. Use a cat brush instead of a carding tool.
Rough needle also works well when building big sculptures and you really need to get the fibers penetrate.