Reply To: Belt Type and Size needed for Graves MKIV machine? › Forums › Faceting Machines › Belt Type and Size needed for Graves MKIV machine? › Reply To: Belt Type and Size needed for Graves MKIV machine? August 17, 2017 at 1:03 am #3429 Alan BalmerKeymaster @alanbalmer After 1980, Graves used a 1/8″ round belt. As Mark said, an O-ring of the right size will work. To find the size, just use a string around the pulleys and measure it.