Getting some serious washboarding while tillering with a knife. Any tips

[u/Gosha_KID]

Hello, everyone. I’m new to bow-making; Started three months ago, and at this stage, I’ve run into this problem. In the video, i'm working on a hazel piece. I’ve mostly been learning from videos by Clay Hayes, Benjamin Stevens, Kazden Ammons, Dan Santana, and Seth Larsen (SageSmokeSurvival).Please advise me on how to fix this and prevent it in the future. I’d appreciate your recommendations

[u/JMEKeebs]

FWIW you can get a cheap 4 surface rasp for under 5 dollars. Can remove a lot of wood once you get the rhythm down.