Like I said earlier, these have the signs of being home made. They are made of steel. IF they were South Bend made, they would be made of cast iron. Plus, the SBL one's are a little different. They are not as hing as these are, plus they made theirs so two short blocks were used on the headstock and one long block for the tailstock. For the cross slide, there was a offset riser block that went between the compound slide and cross slide, that would give you extended reach for the larger turning radius.
Ken