Laying out joints for consistent reveal

[decibel]

OK this is probably a very newbie question but I'm building a nightstand. The sides are frame and panels and I'm about to join the sides together. I've seen the top rail (I guess that's the best term) will be dovetailed into the side leg. The sliding dovetail videos / articles show them matching the male piece to a female slot already cut out. I would think I'd have to go the opposite to ensure I get the slot placed in the correct spot unless there is some better way to lay it out.


I'd also have to do the same from a couple other mortise and tenon joints that I want to keep 1/4 reval around as well. I'd think I'd cut the tenon out and then the mortise to match it based on the where the tennon will lie with the 1/4 reveal.

Not sure if a picture helps I've having a hard time explaining it.

 

[willarda]

Its a lot harder to cut the slot than the dovetail. Just the same with mortise and tenon joinery. You fit the tenon to the pre-existing mortise. In general, you want to cut the part of a joint first that is referenced to other design elements in the piece. This keeps everything square, etc. You can trim the dovetail to fit to the slot mcuh easier than trying to trim the slot.

It loooks like from the pic that your are using carcase type dovetails (half lap, set in on the top of the leg or the side member)? the most critical feature of these is that the shoulder to shoulder length of all of the rails be exactly the same so that the assembly is square. this is excepting of course the situation where the legs are not perpendicular to the structure.

 

[Ray Martin]

Patrick,

When it comes to dovetail joints, woodworkers will argue which to cut first... till the cows come home. The only thing I can suggest is cut one, put the pieces together, clamp them to hold them in place, then use an X-acto knife to mark the matching piece.

For mortise and tenon joints, I generally cut the mortise first and then cut the tenon to match it. I'd cut a tenon that's a wee bit to large and sneak up on a nice snug fit with a shoulder plane or some fine sandpaper. I think it's easier to adjust a tenon that it is to adjust a mortise. I would also suggest that a tenon does not have to be tight on all four sides. Only the cheeks have to be snug. In other words, if a mortise is 2 inches from top to bottom, the tenon could be 1 3/4 inches from top to bottom, so long as the cheeks (sides) are snug against the sides of the mortise.

You can eliminate a load of squeeze out by applying glue to the insides of a mortise only. The tenon will push the glue down into the mortise. If you apply glue to the sides of the tenon, the edges of the mortise will scrape the glue off and leave it at the surface / shoulder, where it will squeeze out onto the exposed parts of your work.

Hope this helps a bit.

 

[Joe Scharle]

Actually, by making the tail first you have a template for the socket. Lay the tail on the leg end and mark the socket. For the reveal you can lay the apron on a pair of, 1/4" (pick a size) pulley keys, bring the 2 leg ends under the tails and mark. Saw inside your lines and chop out the waste. You'll probably finish fit the tails by splitting the mortise lines. It's just easier to sneak up on your final fit.

I make mortise & tenon joints this way. Tenon sized (a little at a time) to fit the mortise. So much can go wrong in cutting / chopping a mortise, and since it's usually in a major part, I make the tenon FIT the OUTCOME of the mortise slot! I can cut 7 mortises exactly 1 1/4" long, but I'll lay even money one will Ooops to 1 5/16" before I'm through.

 

[decibel]

Good info guys. I was struggling with how to layout the the dovetail slot if I say wanted the final board that was joined in it to be 1/4 from the edge. Simply measuring 1/4 from the front and sticking the dovetail there wouldn't work since the dovetail is centered in the rail stock.


Mortise and tenon is a little easer to do or if I had all mortise and tenon / joinery for the front rails then I'd just put all the mortises in the same place and call it a day. I just fear having the dovetailed top rail not in the same plane as the the mortised rail below it that makes up the bottom of the drawer.

I have a tendacy to overcomplicate things which is why I had to ask before I go figuring out where to put the joints. I've been lucky so far to be able to use sketchup drawing to determine where to place some items I know there other ways to do things besides measuring and having to rely on CAD I'm a techy at heart :XXcompute