In order to secure rough door openings to the walls, I first used my builder's level to set concrete pavers in cement at the height of the finished floor. The rough 2"x6" door bucks were then set on top of the pavers, leveled and plumbed into position. The rough door openings were fabricated to the outside dimensions of doors already purchased for this project. Rough openings are made at minimum 1/2-inch bigger on all sides to allow for the finished door to fit the rough opening and for shims necessary to level the door in place.
In order to secure the rough door buck into the stone, I drilled a hole in the wood - the diameter of the bolt - and inserted the 8"anchor bolt (see above photo). Also notice in the top-left photo of the collage, that I counter-drilled a larger diameter hole that does not go all the way through. This allows for a large washer, nut and leaves room for a 3/4" socket to be inserted to secure the nut. The nut is secured once the entension part of the anchor bolt is cemented into the stone wall against the door frame.
The bottom-right photo in the collage shows the finished wall build around the the rough door buck. Two additional anchor bolts will be placed vertically, on each side of the frame of the rough buck, as the cob is applied to the wall on top of the stone stem wall.