Diana Hanks walks through how to sharpen Nordic skate blades, using several different styles of sharpening jig. She has an older video on sharpening as well.
Dan’s YouTube channel is full of invaluable advice, safety tips, and beautiful videos of skating, primarily in New York and the Lake Champlain area. Highly recommended.
Fantastic video and article from National Geographic about Henryk Trygg and Mårten Ajne, their pursuit of very thin black ice (kids, don’t try this at home), and the amazing sounds the ice makes.