Is there a difference in quality and structural strength between dovetail and pocket screw joinery for cabinet construction...If not, why is dovetail always haled as the choice for cabinet and drawer construction...Is it mainly aesthetics
There's a big difference. A dove tail is a locking style joint that requires no glue or mechanical fastener to hold, though they are usually glued. A pocket screw is a mechanical fastener that relies on the strength of the fastener and the density of the material to maintain a good joint. That is not to say that pocket screws aren't an excellent fastening system, just that they are different, not quite as strong, and depending on what you're trying to do either not aesthetic or plain and simply the wrong fastener to use.
Specifically for cabinet construction, I've never used dove tail joinery on the drawers which is the only feasible place to use them. Pocket screws I used to hold face frames together and attach the face frames to the cabinet so that there are no visible nail holes to fill and stand out. They can also be used to hold the carcass together. A well made cabinet carcass is uses dado and rabbet joints for strength, any fastener you use is merely to hold things together while the glue dries.
I have to agree with Spruce. The value added by dovetails is in perception rather than reality. The dovetail joint compensated for older less effective glues. To day with modern glues and joiner techniques that are faster and just as strong, the dovetail joint has taken on a mystic persona.
Wow...I think I actually have an opinion on this one that differs from the wise.
First off...there is a recent issue in FWW that compares different joints for strength. Although I do not totally agree with everything printed...it is a very good article and well done analysis.
I should say I have always been a fan of pockets screws...but only when they are used properly. IMHO there should be NO stress going through the screw/wood interface. As Spruce said...the screws are there just for the glue to dry.
In regards to dovetails...I used them in all of the drawers I constructed for my cabinets. Is it overkill??? Maybe. But the repeated load of pulling on a drawer does induce stress into the connection between the front and the side pieces. Depending on how hard you pull and how much mass you are accelerating would dictate how much stress is passing through the connection. A dovetail is unique in that the stress passes through the joint in compression from the pins to the tails. The glue itself is not put into tension...where it will eventually fail. If there is anything I have learned through WW, is that the lower stress levels in the materials translates into something that lasts longer and works better. Once the stress levels (in either the wood or the glue) get sufficiently high you will get systemic failures (drawers coming apart, cabinets buckling, etc.) For most applications we do not worry too much about the stress levels as they are sufficiently low. But something that gets cyclic loading (like a drawer) I think it is better to err on the side of caution and use a connection that has proven to last for a very long time.
But then again...WTH do I know? :)
All very nice comments about dovetails but I don't totally agree.
Drawer lock joints will hold up to the stress and is faster to make.
Cadillac of joints because it is promoted as such by wood working purist.
Difficult and expensive equipment to make dovetails? A dovetail saw and a sharp chisel is all that is needed. Once you learn how to do them they can be done fairly rapidly, the time is in the layout. Plus there are a lot of jigs on the market today that are not the expensive.
Just my opinion of course.
Don't forget Walt is an engineer........... I hear he still uses a pocket protector and has a slide rule.............Shrugs shoulders. :D