A related myth—that the Holy Lord hinges were intended to protect the house from witches—regularly makes the rounds as well, even in hardware stores!
HL hinges are a stronger version of simple symmetrical H hinges. They are useful for supporting the weight of a heavy wooden door. The key is the extra supporting arm that fastens to the door. This piece can be on top, in which case it would look like an HΓ, or on the bottom, where it resembles at L, or it can be mounted on the other side as the mirror image of these two. Leaving aside the hard fact that many colonists had little or no interest in religion, no documentation exists for the belief that their hardware had any symbolic value.