The real way to fix this is to readjust the jig to your shaft. The screws in the front and rear of the jig allow you to adjust the offset of the shaft in relation to the clamp. Put and arrow in and set a clamped flething on it then adjust the jig back and forth until you get 100% contact between the fletching and shaft. If you're having to shim things and monkey around with not setting the fletch all the way into the clamp, something is out of adjustment. I have to readjust mine every time I switch to a different shaft diameter but I've never had issues fletching anyhting from a 2512 aluminum all the way down to a Superslim A/C or uncut flu-flu's down to Blazers. Play with it a bit and you'll get her figured out.