Note: It looks like the screws were cut off. So, when the anchor is hammered in, the ridges dig in and get compressed, which holds the anchor in place. The hole for the anchor is 3/4', but the top ridges are slightly larger. To keep the hole saw steady without wobbling, you can first drill a hole in a piece of wood and then put that hole over the anchor then drill through the hole. If you use a 3/4' hole saw to drill the top part of the anchor, that will remove the ridges around the top of the anchor, which will reduce the risk of surface damage. Scoring around the anchor a little bit and having the copper coupling sit in the scored area should reduce the risk of surface damage, but pulling an anchor always risks damaging the deck. Then, hold the bolt and tighten the coupling nut to pull the anchor.
The bolt will need to be about 6 to 8 inches long to accommodate the anchor, coupling and coupling nut.
Then, screw in a long 5/16-18 bolt with 2 big washers and a coupling nut above the washers. A 3/4' copper coupling should fit the scored area around the anchor. Then, drill and tap the center hole with a 5/16-18 tap. To remove an anchor, first lightly score around the anchor to reduce contact with the deck.
