A range of doors are supplied with solid wood lippings that have leading edges on both sides (certainly the ones we have at SWD do). Leading edges are common from most European door manufacturers especially on the higher quality pre-finished doors. The purpose of a leading edge is to obtain smaller gaps around the door when it is hung. The below explanation by the British Woodworking Federation sums this up nicely:
“The reason why it is common practice to apply a leading edge to a door stile is that, in the action of opening the door, the corner of the door stile furthest from the hinge knuckle swings closer to the rebate platform of the jamb and could lead to the door “sticking”.To maintain a clearance between the locking stile and the jamb either the clearance between the stile and jamb would need to be increased overall, which to some is unsightly, or a leading edge or slight chamfer can be applied to the stile to slightly increase the clearance at the corner that moves closest to the jamb. Applying a leading edge to the locking stile allows a closer fit of the door in the frame than would be possible if the stile was kept square.”The fact the leading edge will be on both lips of the door needs to be kept in mind when installing the doors so the leading edge is on the correct side of the door when it is hung. The widest part of the door should be seen meeting the frame when the door is closed (see diagram below). Also important to note is fitting double doors with leading edges. We do not rebate our double doors, so the leading edges need to be positioned correctly and then a brush strip will need to be routed into the slave door which hides the gap. If, for example at SWD we are informed of the handing/master door on doubles we can supply one door with leading edges and one door without if the carpenter prefers this when fitting.