You can buy the dogs from the beveling machine manufacturer- they get spendy- Mathey's 8" button tabs cost me about $75 a set but that was years ago. H & M hypoid dogs are a more complicated machined unit and I don't know how much they go for. If a guy was going to make his own, the Mathey rep I spoke with told me the length of the dog could be derived from this formula: ID of saddle on machine - [minus] OD of pipe to be cut divided by 2. I guess a guy could try that out with some long bolts or allthread and double nuts to see if that formula was correct and then get something machined up.