I am wondering where I can get a 4" long 5/16" - 18 piloted tap? And i was wondering if anybody has used 5/16-18 A-joint pins before? or are the threads not big enough to give it strenghth there? I am wanting a tap to do the joint pin just to let u know. just wondered about using it for the A-joint for now tell i get a 3/8 - 16 piloted?