I am making a case for a cabinet which is joined at the corners by through dovetails. The dividers between an upper and lower section and the dividers between drawers are held by sliding dovetails into the sides of the case. The panels are 21 inches wide by 48 inches long, maple, with poplar as a secondary wood for some of the dividers. My problem is that once I rout the mortise with a dovetail bit, (3/8 in deep in this case, in 3/4 in thick panels), I can’t seem to get the dovetail key on the divider to fit well. It either binds or is too loose. There is no good way I know of, of planing this to fit, since even a rabbet plane can’t reach into the corner of the doveltail key.
The way I routed the ends of the dividers was to clamp a 2×4 to the panel, flush with the end of the panel to support the base of the router, with a guide. It was too tall a panel to attempt on the router table. Now I’m having to try to shim it with veneer. Any advice appreciated. Thanks a lot.
Jay
Replies
A 21-inch non-tapered sliding dovetail is very difficult. If you make it tight enough to not rattle, it is nearly impossible to slide in to place. My first suggestion is to not use a sliding dovetail that's more than 6-8 inches long. Instead, I use dowels (read Krenov before you laugh at me). I use a drilling jig intended for shelf pins to put a 1/4" dowel every inch along the joint, so it is darn strong. The other suggestion is to make the dovetail taper, so it is wider at one end. This means that the joint gets tight in only in the last few inches of insertion.
There's also an elaborate scheme that I would call an interrupted sliding dovetail. To describe it, let me start from your long non-tapered sliding dovetail. On the male part of the dovetail, cut off about half, in say two inch segments. That is, there is a dovetail, then nothing, then the dovetail, then nothing, all along the length of the joint. On the female side of the joint, cut short little dados along the the joint in that same 2" on/off pattern. Those dados are a little wider than the dovetail, but narrower than the board is thick. To assemble this joint, the male dovetails insert into the female dados, and then the whole board needs to slide only two inches to fully engage all the male dovetails into the female dovetails.
Edited 4/3/2003 10:29:34 PM ET by JAMIE_BUXTON
I built a bookcase a few years back and the shelves and top had sliding dovetails. It was only 12" deep and I had to taper them. I made a jig I wouldn't start to describe, I probably couldn't. It can be done,devise a way to taper them a little.
Good Luck and God Bless
les
Does the dovetail socket (slot) have to be tapered to exactly correspond to the taper on the dovetail key or can you taper only the part to be inserted, and keep the slot parallel sided? If the taper is slight this might allow easier insertion, but the joint would be tight at only one end. Could you clarify for me? Thanks.
Jay
I have made many of these over the years (sliding, tapered dovetails) by hand. I have never had much luck using a router except to waste some of the wood in the slot with a straight bit. I only do this occasionally based on what kind of wood I am using or how I feel at the moment. You will need a saw that you can buy (I think at Highland Hardware) or you can make your own as I did using a piece of an old tenon saw and a piece of straight grained, dense hardwood. This little saw, which cuts on the pull stroke and a sharp chisel are all you need for the slot. There are a bunch of ways to make the tongue. I find the most critical part of the joint to be the shoulder of the tongue. It is important that it be 90 degrees and flat for the length of the tongue. This is sometimes more difficult than it might seem. I have never made this joint in 24 inch stock and would probably not attempt to do so (this said not knowing the details of the piece you are constructing). As others have noted I would probably make a dovetail and corresponding slot for the last couple of inches toward the front of the piece with a dado for the remainder and figure a way to secure the sides of the carcase from the back when you close it in. With a piece this deep differential wood movement can be a real problem, even using the same species. It seems to me there are many other ways that might be employed that would be simpler and just as effective depending on how the piece is to be constructed and how it will be used.
Wayne
Jay
Just taper your key slightly, I had to take a couple of try's at it before I got it right. I run my taper towards the end that wasn't going to show.
Good Luck and God Bless
les
Jay,
I like to use sliding dovetails as much as possible on wide carcass, but they can be infuriating. My wife bought me the 24" Leigh dovetail jig, and it GREATLY improved the consistency of my sliders. Highly recommend it. Its not as fun as building your own jigs, but I was never able to build one that was as consistent as it is. Just an idea, I know some people shy away from dovetail jigs because they are "cheating", but it works.
Steve
One way to do this is described by Bird in the first of the 3 part secretary article in FWW. It is how he installed the writing surface of the desk in the lower carcase. Basically, it is a dado, 3/16" deep, except for the last 2-3", which is the dovetail socket. The dado is the full width of the divider thickness. To get the divider to have a dovetail on the rear as well as on the front, make it up a bit wide, then rip off the rear, install the divider in the front 90%, and then slide in the rear strip, and edge glue. Hand plane to fit after the glue dries. Taking it apart will be impossible, of course. When I use sliding dovetails, which I like much, I only do 2-3" of the slider. That seems to be plenty of strength.
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