Hey, I've had this problem ever since 1.8 my swords look really glitchy and weird, I am actually making a texture pack and I created this sword for my friend. I don't know whats wrong or how to fix it, its happened with almost every 1.8 sword/tool I've tried! Please help

Screenshot example: http://gyazo.com/7990c2c8d4eedf03e6f0f444ba4b53c6