In this video I explain the math behind kerf bending so you can get perfect bends every single time.
If you already know the Math but want to see how a hand tool can help you calculate the kerfs, I made a video about that:
https://www.youtube.com/watch?v=CIBRmBxTPCA
You can get the STL here:
https://www.etsy.com/listing/980748373/kerf-bending-tool-5012115?ref=listings_manager_grid