Any stance on Ivory or Bone to add to the cue hit? All hogwash?
Not all hogwash, but not as much difference as you may be hoping for. IMO, a bigger factor would be the manner in which the joint is installed. Is it a sleeve? If so, what is the tenon diameter? A 1/2" tenon will allow the joint material to be more of a factor than a 5/8" tenon. To parallel this, the length of the collar will play a role. Longer collars will be more of a factor than short collars. For instance, a 1" long PVC collar on a 1/2" diameter tenon will compress when flexed quite a bit more than a 1/4" long PVC collar on a 5/8" tenon, thus giving a softer hit. Simply put, the more of the material you use, the more difference it will make.
As for natural materials, you'll be hard pressed to find anything harder than fossil walrus jawbone. It's in all likeliness harder than many types of steel. Hippo ivory is pretty dang hard, too.
IMO, what really matters isn't necessarily the material you use, but how you use it. A builder must recognize & understand the purpose of the component. In this instance it's a joint collar. The purpose of a joint collar is to reinforce the wood around the joint pin, to prevent it from splitting. It also gives a solid base for the shaft to rest, and is usually made of something that doesn't fluctuate in dimension with climatic changes. The fluctuation causes the joint face to tweak this way or that, making the cue appear warped. Therefore, a solid, strong, stable material best suits the purpose. A joint collar never was intended to influence playability. It's purpose was to solve the problem of cues cracking & splitting at the joint.
