If you have a complete feather, simply strip the feather away from the quill. It naturally provides a thin even base, much thinner and consistant than can be achieved by grinding. After discovering this trick, and learning tips on here from others, I amm never going back to grinding...too much work. That said, I have several dozen full length true flight feathers that are right wing, and all my jigs are left wing, so I use these for spiral wrapping flu-flus until I run out of them.