"Making Perfect Dovetails in Less Than Perfect Wood"

	Making great dovetails in plywood takes more work...but not that much more. In fact, if you follow the same steps in all woods, perfection will be more assured.    The wood I am using here is birch ply from a home center — admittedly not as good quality as from a cabinet lumber supplier. Where the poorer quality shows up most is in the layers in between the faces and in the gluing. Delamination is very probable when routing this ply. The following are steps that  I used to get the perfect joint, shown here.
The first step in dovetailing is to rabbet the insides of the tail boards. This is where the most tearout can occur. It is easy to eliminate, or at least, minimize tearout. All you have to do is score the inside where the top of the bit will cut. Since I have the router bit height set at 1/2" exactly, I score at that height.    In the photo, on the left, I am using a tenon marker/cutter to score the mark — all it takes is one or two passes. At the right, I have simply measured the 1/2" and am using a utility knife to make the score. Both methods work well.
	The rabbet cuts are as clean as can be. So, on to the next step.
Here, I have clamped a piece of 1/2" MDF in front and behind the two rabbeted tail pieces. MDF machines very well and will keep the plywood from chipping. Other stock could be used.
	The sandwich is clamped securely, and I can make the tail cuts. I purposely make the cuts very slowly. I do not want to rush the cutters. By the way, when you flip to do the other end or place other pieces in the sandwich, you can use the same MDF pieces. Carefully keep the same alignment, and these pieces do not need re-cutting.
Here are the elements of the sandwich after cutting. You can see how clean each of the tails are in both the MDF and the ply.    Routing the pins in the end pieces is done exactly as before. If you take the cuts slowly, there should be minimum tearout.
	This is the final results. Both the outside and the inside of the corner show a tight and crisp dovetail that will glue up well — and look great.
Routing MDF and plywood calls for extra sharp and clean router bits. This was a new bit when I started these drawers. Now it looks "burned." It isn't. The MDF and glue of the plywood leaves residue that needs to be removed.
	A quick scrub with bit/blade cleaner and a 3M scotch brite pad brings the orange bit  back to "like new" condition.
I use a fine diamond file to gently remove any burnt residue from the carbide edges. I try not to touch the actual cutting edge. The bit should look as good as new before returning to its storage place.    Next week, I will finish this cabinet and start the first real project — a Stickley style writing desk that I will adapt to hold a laptop.