To insure a tighter fit at the swinging edge this edge should be slightly beveled inwards.
In attaching a butt-hinge, the essential thing is to sink the hinge into the wood, exactly the thickness of the knuckle.

The gains may be cut in one or both of the pieces to be hinged together.
With these matters determined proceed as follows: In the case of a box cover, the hinges should be set about as far from the ends of the box as the hinge is long.
In the case of an upright door, locate the hinges respectively above and below the lower and upper rails of the door.

Mark with the knife on the edge of the door the length of the hinge, and square across approximately the width of the gain to receive it.

Do this for both hinges.

Between these lines gage the proper width of the gains.