Hi. I'm very new to knife making and thought I'd start with a knife blank to get my foot in the door. I purchased a Helle Utvaer blank and it seems that the holes in the tang are an odd size. In between 17/64" and 9/32". I'm guessing they're 7mm. I wanted to use tubes in the handle cause that's how it comes from factory and to also attach a wrist loop but I'm having trouble finding any tubes that size. Perhaps I'm to ignorant and just don't no enough about the process. Can anyone steer me in the right direction?