Rick:
The Graves doesn't have a 1/10 splitter. It is a Mark I, and I believe it is an original one.
A friend lent me his old Prismatic, which has a great protractor and a splitter, too. But the cheater housing is cracked and using it yields entirely unpredictable results. I emailed the Polymetric guy last week and he hasn't responded. So yesterday, I finally got the quill and mast assembly apart and tried repairing it. I epoxied it back together and reinforced it with a metal plate but it recracked as soon as it was tightened. I am going to have to mill a new one; I'm debating about using nylon or aluminum. It needs to be strong and flexible, and either of those are a bear to thread. I don't know if the nylon would strip out when you tighten the screws. I could cast it out of bronze, but I think that would be too much weight.
The last stone has one or two "bent" facets due to the cheater; it either moves not at all or a whole lot. I finally resorted to Marks-a-lotting every facet to see how far the cheater was going. The Graves cheater was much easier to work with.
Other than the cheater, I'm impressed with the Prismatic. It's nice and level, has a variable speed motor, the protractor and fine adjuster are great, and it has the dial height adjustment like a Facetron. But the cheater is a mess and it has to be dealt with.
Debbie K