sliding dovetail options

[DavidF]

I have a design/construction decision to make and would like some input.

On the front lower base of the bedside cabinet I need a sliding DT on the lower shelf/bottom of cab to hold the sides in firmly. For aesthetic reasons I want the DT to show on the front face. Now I have a couple of options. One is a full length sliding DT, going straight front to back and cut a matching tail on the shelf (cherry veneered Ply). Now we all know that getting a long SDT to fit all the way through can be a problem and you end up bashing the **** out of it to get it though, this wouldn't be a problem if the side of the case was perfectly flat, but if the joint is tight it would only take a slight change in thickness or flatness to bind the joint. Now an option is to cut a shallow, 1/8 deep dado in the case side the thickness of the shelf (1/2). Then cut a full length DT on the edge of the shelf, but then cut most of it away leaving a short (1") sliding DT on the front end of the shelf. The shelf is inserted from the front into the dado up until the DT "ear" makes contact with the front and then this is scribed and a DT socket cut into the face of the case side. This gives me the pulling power of the DT but the ease of fit of a dado. Is that clear? Question, should I do this? has anybody else done it? BTW, sides are solid cherry, with 2 joins to make up the width and is 13" wide. The chances of them being perfectly flat are slight. What do you all think - worth the effort of the mixed dado/DT joint?

 

[DavidF]

Could you taper the DT on the shelf enough to slide in easily without compromising the hold? IOW keep the DT in the sides and on the bottom of the shelf straight but taper the DT on top of the shelf.

I had considered that Mike and that still may be an option - You really need to taper both parts of the join by about 1 in 250 for a good fit. I have a lot of experience with taper SDT:lol: if you get it wrong it looks terrible DAMHIKT. I am only going to glue the front 2" so at least I don't have the additional problem of the joint swelling due to glue. The standard full SDT is the easy way if it goes well

 

[Travis Porter]

Mixed dado/DT is my vote. If the panel is going to be plywood, can't you make the front piece of the plywood say 2" wide and let that be the dt part? Then make the rest just a dado to allow the side to expand and contract?

 

[DavidF]

Mixed dado/DT is my vote. If the panel is going to be plywood, can't you make the front piece of the plywood say 2" wide and let that be the dt part? Then make the rest just a dado to allow the side to expand and contract?

That is a good alternative and doesn't involve making a tricky cut in the ply.

 

[SSuther]

I just did this on a small chest in solid walnut, and it seems to have worked out pretty well other than the wood is quite brittle, and I had a bit of damage to the dt socket edges where the angel is acute and the cut was cross-grain. Mechanically, it works well. I made the dovetailed rail out of a strip about an inch deep, the glued it to the frame behind it. You could do the same by just making the shelf separate from the dt rail, then gluing then at assembly.

 

[DavidF]

I just did this on a small chest in solid walnut, and it seems to have worked out pretty well other than the wood is quite brittle, and I had a bit of damage to the dt socket edges where the angel is acute and the cut was cross-grain. Mechanically, it works well. I made the dovetailed rail out of a strip about an inch deep, the glued it to the frame behind it. You could do the same by just making the shelf separate from the dt rail, then gluing then at assembly.

I just laid this out on the cad drawing and it looks good to me. If I wanted to go mad I could tongue and groove the front piece to the plywood base.

Do you have pics of the walnut cab, I would be interested in seeing it.

 

[Alan in Little Washington]

I think the best way is to go with what you described- a 1" dovetail on the front and dado the rest of the way to the back of the cabinet. You need to make sure the centerline of both dovetail and dado are the same. Unless you use two routers with a DT bit in one and straight bit in the other you'll have to switch bits so you can use the same router guide bushing and jig. It might also be a good idea to make the bottom in two pieces like the CAD drawing.

Another option that looks nice and reduces the problem SSuther had is a "captured dovetail" (dovetail within a dado) at the front. One of the recent issues of FWW or another mag had an article on how to cut those. If you are interested I can dig through my mags.

What kind of back will the cabinet have? Ply set and stapled/glued in a rabbet? I ask because you could also dovetail the back piece of the shelf to help hold the cabinet together, though it might be hard to get perfect alignment with the front part of the shelf/bottom.

To limit tearout use a front backer board or make your sides a little wider so you can trim them after you cut the dovetail slots.

 

[DavidF]

I think think the best way is to go with what you described- a 1" dovetail on the front and dado the rest of the way to the back of the cabinet. You need to make sure the centerline of both dovetail and dado are the same. Unless you use two routers with a DT bit in one and straight bit in the other you'll have to switch bits so you can use the same router guide bushing and jig. It might also be a good idea to make the bottom in two pieces like the CAD drawing.

Another option that looks nice and reduces the problem SSuther had is a "captured dovetail" (dovetail within a dado) at the front. One of the recent issues of FWW or another mag had an article on how to cut those. If you are interested I can dig through my mags.

What kind of back will the cabinet have? Ply set and stapled/glued in a rabbet? I ask because you could also dovetail the back piece of the shelf to help hold the cabinet together, though it might be hard to get perfect alignment with the front part of the shelf/bottom.

To limit tearout use a front backer board or make your sides a little wider so you can trim them after you cut the dovetail slots.

Thanks Alan, the back is glued into a rabbet at the back so that will not need a DT.

I think I will use a separate front piece of cherry that will be approx. 2" wide DT'd into the case side and then a Dado running through to the back panel rebate.

 

[Joe Scharle]

David I did this on chest of drawers. Not shown are the dados in the panels.
BTW long sliding DTs can be managed by segmenting the male piece. I typically cut it flush every 2 inches for 2 inches.
Joe

 

[DavidF]

While we are on the subject; I deliberated over making the base a frame and panel like BladeBurners or going with the lipped ply. I couldn't come up with convincing arguments for prefering one over the other in my design. I guess if I had drawers running on it I would go with the solid frame with a panel.

 

[Travis Porter]

I would say since it is not a drawer assembly go with the ply. I do the frame with panel using 1/4" ply to reduce the overall weight more so than anything.

Cheers

 

[SSuther]

My arrangement is basically like you've shown here. Regarding the captured dovetail, I've got that issue of FWW and that approach does look nice, but you still have acute angles across the grain. I think I had breakout problems because my wood is very old air dried walnut and some of it is quite brittle.