Like all crafts, it takes time to develop the skills necessary to achieve spectacular results. The more you facet, the better you get. Yes . . . In most cases. We stock parts on models dating from the early '50's.
Most part are interchangeable between various models.
It depends on the age of the machine, and how much you want to do. Start by giving us the serial number, or age of your unit, and we'll explain what can be done, and the cost of doing it. About 3 degrees. Critical angles are functions of the refractive index for a particular gem. Main angles are choosen by convention, and are selected to give maximum brilliace.