Woodworking: A Better DIY Joinery — The Sliding Dovetail

DIY is all the rage these days. The internet is overflowing with DIY websites, “how to” tutorials, downloadable plans. The popularity of this “genre” is that you can do amazing things with little or no previous knowledge or skill.

When it comes to woodworking, there is a lot to be said for that. There is certainly a broad field of woodworking that requires immense skill (and is often made easier by very expensive tools). Turning wood on a lathe, for example, requires not only a lathe, but a good bit of practice and training to master the technique.

That said, building a picnic table or a bookshelf is something that anyone with very limited tools and woodworking skills can do reasonably well. However, it’s often not that difficult to do things well. Why use a crude and inferior joint technique, if a far superior one can be made just as easily? And that brings me to the subject of this post.

Most of the DIY sites (the ones making money) are being sponsored by a tool company such as Kreg or Ryobi, so they are constantly telling you to join everything with pocket screws using your Kreg jig and your Ryobi drill. I get that they have to make money, but there is a place for pocket screws — I use them often — but why advocate that type of joint when another is called for?

Worse, you often see “woodworkers” demonstrating “glue and screw” joints such as the one pictured here. Yeah, I get that he/she is making this with plywood and will putty in the screw holes and paint the entire thing, and in the end the screws won’t show. But it’s an inferior joint for a shelf. The shelf should at least be set in a dado joint which can be cut in less time than it will take you to fiddle around with puttying and sanding at the end of the project — and the joint will be 100 times stronger. And a glue and dado joint for a shelf won’t require any screws — no screws on the outside to putty, no ugly pocket holes on the bottom side of the shelf that you hope no one stoops down to see.

What if you want to build a bookshelf out of cherry or oak? I hope you aren’t planning on painting five dollar a board foot hardwood. I’m here to tell you that you don’t have to settle for painted projects to cover shoddy workmanship. You can build a high-end looking project with the same tools and experience you are putting into the DIY plans you are downloading from the internet.

A dado can be cut with a table saw, radial arm saw, a router, or with a handsaw and a chisel. There is no reason to not at least be using dado joints when they are called for. Sure the dado joint will show at the front of the bookcase, but if you will be using a face frame, the face frame will hide that.

What if you aren’t using a face frame. Let me introduce you to another extremely strong and invisible joint — even stronger than the dado joint — that you can cut in minutes. This will require a router and a router table.  If you are doing ANY woodworking, a router, a table saw, and a miter saw are absolute musts anyway.

The sliding dovetail joint is a locking joint. A shelf could theoretically pull out of a dado joint.  Not so with a dovetail joint. This is a common joint in cabinetry, particularly with drawers. It looks intimidating, but let me assure you a 7th grader can make this joint.

If I’m using 3/4″ stock, I generally use a 1/2 inch dovetail bit. I set my bit depth to approximately half the thickness of the stock. It doesn’t have to be exact, because we will custom fit the tails to the slot.

The jig is simple. Make a square box with 3/4″ stock laid flat, exactly the width of your router base, so it can’t move left or right. Set the end of the box so when your router hits it (stops), the bit will stop about 1/4″ from the far edge of the board. Clamp your piece to the table and clamp your jig to your piece, and rout your slot. Make a couple slow passes so the slot is cleaned up nicely. Make all your dovetail slot cuts for your entire project without changing your router setup.

Once all the slots are cut, now it’s time to cut the tails. Always do your initial tail set up on a scrap piece of wood. Mount your router in your router table. Take one of your pieces with a slot and turn it slot down so you can see the slot. Raise your router bit until it just touches the bottom of the slot, then lower the bit back down about 1/16 of an inch. You can always tweak later. If your tail is too short, raise the bit. If the tail is too long, lower the bit. I usually don’t need to. You want the tail just slightly shorter than the slot so there will be about a 1/32″ to 1/64″ gap between the tail and the channel for glue surface. If it’s too snug it will starve the glue joint and may also leave gaps in the corner mating surfaces.

Once the bit height is set, move the fence so the bit is barely outside the fence and make a pass on each side of your scrap piece. See if it will fit in your slot. Hopefully it’s way too big. That’s what we want. Now you can move your fence back about 1/16″ of an inch and make another pass on each side. Make very small fence adjustments. Keep in mind because we are making a pass on each side of the board, a 1/16″ fence move results in a 1/8″ change to the tail-piece. Check fit again. Once it gets close, make smaller adjustments to the fence. Once the piece will start to go in, but is still too tight, you can often just make another pass or two without any fence adjustment to clean up a bit of stray material and get a fit. We want a good snug fit. If you need to tap it with your hand to get it to go in, that’s good. We don’t want to have to pound it in with a hammer though.

It shouldn’t take more than a couple of minutes for this whole process to get the perfect tail set up, then you can cut all your tail pieces with confidence.

Now that we have a perfectly fitting tail, because we are making a hidden joint, the tail-piece won’t slide all the way in.

Slide it in until it hits. Use a chisel or small saw (coping saw works well) to cut out the dovetail notch extending. I like to saw horizontally across the grain, the take a chisel and tap the piece out vertically with the grain.

Then because the end of our channel is rounded from the router bit, take a utility knife and shave the corners where we just notched out to round it off a bit and you’re done.

Tap the board back out of the groove, flip it around and slide it back in and — Presto — you have a completely invisible joint that will still be holding strong 100 years from now. A little glue in the bottom of the channel and on the end of the tail is all it takes. Of course, clamp your glue ups until they dry. Usually 30 minutes clamp time is sufficient, but don’t stress the joint for 24 hours.

So just because you are a DIY’er, don’t be intimidated by proper joinery techniques. Most of them can be done well with basic tools and just a little practice. The first time you attempt this, it may take you a half hour or longer, and several pieces of scrap wood to get the setup right. Once you’ve figured it out, the next time and the time after that, you will be knocking these out it minutes.

If you’ve never made a sliding dovetail joint, go to your garage or shop, grab a couple of pieces of scrap wood and give it a shot, then let me know how it went for you. You’ll be making stronger and better looking projects in no time.

Antique-Looking Finish on Shaker Style Entry Table

The “stain-over-paint” technique I’m going to share with you today can be used to achieve a wide variety of antique-looking or “distressed” finishes.

This is an overview photo of the Shaker-style entry table I made using this technique:

You should always practice on a few pieces of scrap wood that is from the project you are working on, to make sure you will achieve the look you want.

In this example, I painted it with one coat of “Antique White” latex paint.  I didn’t prime the wood first or use paint with primer in it.  On new unpainted, un-primed wood, will always absorb a lot of the paint on first coat, leaving an uneven coating where porous areas look almost like natural wood and other areas have good paint coverage.  This creates the effect I want.  Now when I stain over the paint, the stain will absorb in some areas more than other creating a “mottled” look as shown below:

You can see that in some areas the stain is darker than other areas, and in the light areas a bit of the white paint shows through.

I used Jacobean stain for this.  Jacobean, on its own, gives a aged-wood sort of color.  It’s a rich reddish-brown, leaning toward the yellow spectrum, as the closeup below demonstrates:

As I previously mentioned, this technique can be used to create a variety of “distressed” appearances.  If you want a distressed paint look, rather than a distressed stained look, paint you furniture whatever color you want (green, blue, red, white, etc.).  For the distressed paint look, you will probably want to prime the wood, and give it at least two coats of paint, so you have a nice even painted finish.

Once it’s painted, there are two techniques you can use:

1. Stain the piece normally with a brush or rag, let it set about 5 to 10 minutes, then wipe the excess off with a clean rag, leaving mostly natural paint color, with stain darkened areas.
2. Use a stain rag or brush that has had most of the stain removed (so that when you rub or brush a clean board, you just get dark smudges) and go over your piece with that, just adding the amount of darkening you want.

I would also suggest trying this technique with Ebony stain.  It leaves the wood with an old grayed appearance, rather than the yellowed aged look the Jacobean creates.  Both are very nice distressed looks.

Have you used this technique before?  If so, or if you try it after reading this, share your experiences and results in the comments.

An Easy-To-Make Heirloom Toy Box

Last year my daughter-in-law asked me to build her this toy chest she found on Ana White’s website.

After a few delays, I finally got around to making her my version of Ana’s chest. Here’s what mine looks like before painting or finishing:

 

Now, my title says it’s an “heirloom” toy chest — which means it can be passed down to the next generations. That promises durability. Ana’s plans are known for their simplicity. Those with no woodworking experience and very limited tools can use her plans to make things — and that has some appeal.

However, butt joints are the weakest of all joints. You can glue a butt joint together and nail it, and the next day after it has dried, you can break it apart with your bare hands. The overlapping joint I use here, I can glue it and cross nail it with 16 gauge brad nails and after it has dried I can put it on the floor and stand on it with all of my 200 plus pounds and it won’t as much as creak. You’ll have to break the board to break the joint.

If that sort of strength and durability appeals to you, then these small and fairly simple changes are well worth the effort. All you need is either a router table and a 3/4″ straight router bit, or a table saw with a dado stack and you can build this box. A brad nailer or finish nailer is nice too, but not necessary if you don’t mind hand nailing and using a nail set.

So here’s my first change:

 

In the base, I make a 3/4″ dado cut and a 3/8″ rabbet. In Ana’s plan, the bottom of the box was just butted up against the side panels and screwed or nailed to it. This is a very weak joint. If kid’s climb into the box, you risk the bottom eventually giving way as screws work loose. Secondly, Ana has the box attached to the base in the same way. Everything is just floating, suspended by screws or nails. I find this to be weak construction. If it will only hold a few teddy bears and kids will never climb in it, perhaps it doesn’t matter, but I’d rather go for durability.

By fitting the bottom into the dados in the base, it isn’t ever going anywhere and it doesn’t need to be screwed or nailed to stay put.

The rabbet allows an overlapping, cross-nailed joint, which is incredibly strong as already mentioned. This is demonstrated in the photo below.

 

If it isn’t self-explanatory, cross nailing is incredibly strong because the strength of a nail is its perpendicular holding power. If you nail something and then pull on the board parallel to the direction of the nail, you can easily pull the board off the nail. However, if you try to pull a board perpendicular to the nail’s direction — well, try it and let me know how that works. With cross-nailing, regardless of what direction you stress the joint it will always be stressing perpendicular to at least two nails. That, coupled with the strength of the increased glue surface in this joint makes it one of the strongest joints you can make short of a dovetail or mortise and tenon joint — and it’s very easy to make. If you are using 3/4″ stock, then make a 3/8″ by 3/8″ rabbet in each end, and glue it up and cross-nail it. This base is as solid as the rock of Gibraltar.

Next, I made 3/4″ dados in the top side of the box bottom. See photo below:

 

The joints don’t look flush and tight here because the haven’t been clamped, glued and nailed. They are just loosely dry fitted for demonstration. The side panels will fit into these dados, giving them added strength and stability, and eliminating any possible gaps in the joint seams.

Pre-drill into the center of the dados until you come out the bottom side. Do this all the way around the dados. The apply glue to the dados, install your side panels (they are also cross-nailed, overlapping joints). After the side panels are installed and nailed together, turn the box over and you can clearly see where the screws go. Counter sink these screw holes and then secure the side panels with 2″ self-tapping wood screws from the bottom. (I use Kreg screws, but you can use drywall screws if you want).

From this point on, you just add your top frame and molding an you’re done. I built the top frame to print (butt-joined them), but attached them with two pocket screws per joint from the bottom side. The molding hides the pocket screws, and it’s a stronger joint that nails through the end.

The moulding and decorative edges you use is a matter of personal preference.

If you make one of these, leave me a link to your photo or blog post in the comments. I’d love to see what you do with this.