Saves me a lot of time when I'm boring holes in inactive french doors. I cant use a jig because the astragal is in the way, so I drill an 1/8 hole through the door with a 6" bit and this block before going to the hole saw. Perfect holes every time and i only have to mark one side of the door, very worth the $8.
T Perk If you look at the placement of the block he was off there which caused the hold to be off a bit. He was just showing the concept not trying to get a perfect hole.
