JOINTS

A number of types of wood joints. 
Some lend themselves to theatre use, some do not.

Boards have:

Strength depends on surface area of the joint.

• Face Joints:
• Edge Joints:
• End joints:
• Combination joints.

By far most common in theatre:

BUTT JOINTS AND LAP JOINTS.

In theatre, the gussets are corner blocks and keystones.

Gussetted  butt joints:
Cornerblocks and Keystones
Fastened with 11-nail or 10-nail nailing pattern.

LAP JOINTS:
When two boards overlap.
The strength of lap joints depends on how much of joint actually overlaps.

Face to face by definition

Cross lap         End lap         Middle lap

Half laps are when half of each board is cut away before lapping.


SCARF JOINTS are complimentary tapered;
When jointed it creates a board similar to a whole board.
• Face scarf
• Edge Scarf
Require specialized machinery or great care to make. 
Usually only found on stage in commercially obtained stock, e.g. molding.

DADO AND RABBET JOINTS are similar.
• A groove is cut through a board face to form a dado.
• A groove cut on the edge forms a rabbet. Strong, but rather putzy to make.

MORTISE AND TENON JOINTS:
Strongest of all shop made joints.
Tedious and time consuming to construct, but very strong and stable. 
Used for toggle rail shoes, mostly replaced by cornerblocks and keystones.
Now found in mostly in furniture.

DOWEL JOINTS: simpler replacement for mortise and tenon.
Not as strong but much easier to make.
Commonly used for building furniture.
Edge to Face				Edge to edge:

Variation is the SPLINE JOINT:
 Uses a strip of wood glued into grooves cut in both boards

Splines are a good way to reinforce miter joints

Variation:the BUSCUIT JOINT:

DOVETAIL JOINT:  this joint is usually found only in very fine cabinetry or furniture.
Rarely worth the bother of making in theatre; useful where high strength is needed.
The prime example for this is building drawers in a permanent prop.


There are also  joints meant for joining the long edges of boards.

Tongue and Groove
Ship lap
Spline