A method of joining two pieces of lumber end to end, without increasing the thickness of the finished piece . One usually uses a Tapering jig on a Table Saw to accomplish this cut as Scarf joints tend to be on the order 15 - 20 degrees. Below is an image of a simple scarf joint. http://lh4.ggpht.com/_9Ixo4VM1xMQ/Sh...scarfjoint.jpg Scarf joints can also be extremely complex, involving; cogs, multi-step cuts, and even tenons depending on their application. Below is an example of a complex scarf joint with a Key or Cog.