Recently when i frame on slate coasters it frames perfectly around the edges as it is meant to however when it finishes engraving the finished job is not straight on the slate and always slanted?
I have tighted the eccentric nuts and my belts are also tight
There are two or three other things that can create lost motion.
The only other ‘usual suspect’ is that the set screws or grub screws on the motor drive pulleys can come loose after a while. Check all of them with a small Allen key.
Are you willing to share some images? Occasionally the speed change between traverse speed and engraving speed can be jarring and cause lost motion. It can often be seen in an image.