I took some scions from an old apple tree planted in my grandparents country home in Blairstown, NJ and would like to graft these scions onto root-stock. However, I have no root-stock at the moment. Can I purchase a small apple tree from Lowes and graft my scions on it's branches or do I need a particular variety of root-stock for the scions to take?

Also, can I use root hormone on these scions and grow new apples trees without grafting them onto root-stock?

Background: I'm not sure what variety of apple are growing on my grandparents' property but it's most similar to a Granny Smith. I also believe these trees are VERY old, as the house was build in the mid 1800's and most of the fruit trees surrounding the property were planted by the original owners.