How many times have you read/said that?
Intuitively I thought that a biscuit had to add strength... However, I think because I've seen the statement I don't know how many times... I've actually started to believe it myself. In fact I may have even said it before.
So...sitting here eating my lunch... I did a search which pointed to a web page that compares the "biscuit" joint to mortise and tenon. Here's a quote... the "Authors compare the two kinds of joints in force-versus-deformation response, tested to failure. Data from a limited number of experiments indicates that biscuit reinforced joints nearly equal the strength of the mortise and tenon."
So I'm thinking...have you ever heard anyone say "Adding a mortise and tenon joint doesn't add to the strength of a joint" ? I think that my intuitive feelings have been vindicated...but I'm not structual guy. I wonder if I'm way off track? Is there anyone out there that can explain why I would be wrong?
See " TESTING OF PLATE (BISCUIT) JOINERY AND ADHESIVES FOR APPLICABILITY IN CONSTRUCTING ARCHITECTURAL PRODUCTS"
http://www.woodworking.org/WC/GArchi...abstract1.html