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#1 ·
Milling the parts.

A1Jim suggested I post a blog to describe how I did the double dovetail Joint I used on my Spalted Mango Box so here it goes. I hope people find this helpful and if you have questions please post them and I'll do my best to answer them. I also greatly appreciate feedback on anything.

I was going to show how to make the joint using some scrap wood but since it's just as much work as using good wood so I decided I may as well use good wood and build a whole box. I'll be pretty much making up the design for this box as I go like I often do so any suggestions will be most welcome. The wood of choice for this project is Canary Wood and Jarrah.

Step 1: Mill the front, back, and sides of the box as usual using whatever dimensions you want. For a normal dovetailed box the lengths of the pieces would be exactly the same as the finished box. For this box, subtract twice the thickness of the pieces from the lengths to allow for the corners.



Step 2: Mill a couple a couple other scrap pieces the same thickness and width as the box parts. Length doesn't matter as long they're long enough to clamp into your dovetail jig. I would normaly use some cheap poplar but I didn't have any and I already had a bunch of the canary wood pre-milled so I used that.

Step 3. Mill the 4 corner pieces. The final size should be the same thickness as the side pieces square and as long as the sides are wide. For example: if your sides are 3/4×3 x 8 then make your corner pices 3/4×3/4×3. For now, make them a little wide, say 3/4×1 x 3".

Step 4: Glue the corner pieces onto the ends of the scrap pieces. I used my bench and a couple of blocks to keep them flat and flush. Make sure you've got a good joint and Let the glue set overnight.





Next up, cutting the dovetails.
 
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#9 ·
Cutting the first set of dovetails

I'm not planning on going into all the gory details about how to cut the dovetails, that would be a lengthy blog by itself and it's highly dependant on your choice of jigs or hand tools. I use a Porter Cable Omnijig but I'm sure any jig capable of making a half blind dovetail will suffice. If there's enough requests then I may do another blog on that or could go into more detail on this one.

Step 1: Clean up the glue from the boards that you glued the corner pieces to. Make sure the ends are square, trimming a little off the end if you have to. This is one of the reasons for making the corner pieces oversized.

Step 2: Cut the mortises on each of the corner pieces.

Step 3: Cut the tails on one end of each of the front, back, and side pieces. If you want to keep things simple you can do the same joint on all sides, if so cut tails on both ends of every piece.



This box is much smaller than the Spalted Mango box so I can't do the joints exactly the same way. Instead I'm going to reverse them end for end. That requires a second setup to cut so I'll cut them later after the next step. This should give you an idea what the final joint is going to look like:



I didn't get as far as I wanted to today due to technical difficulties with a router that was auto adjusting. I made several cuts before I realized that the joint I was trying to make looser was actually getting tighter. Once I got that corrected it took a few more adjustments to get the joints fitting right. I also wasted some time due to not setting things up correctly in the first place. The Omnijig is a very cool jig but there are a lot of things that can be set wrong. Just for kicks here's what happens when you use the D5 bit when your supposed to use the D4 bit:





Next up, cutting the remaining dovetails. I'll be travelling out of town next weekend though so the next blog may be a couple of weeks from now.
 
#12 ·
Attaching the Corners

Well I'm back from California. I enjoyed the trip but it was raining more there than it does in Seattle this time of year so I'm really glad to be back home where I can work in my shop on rainy weekends.

Next step is to cut the corner pieces off of the scraps that they were glued to. Since they are small pieces I used a miter sled on my table saw and let them fall off. These is the other reason I made them a little wide when I cut them, so that there is room to cut them off with out leaving traces of glue on them.



Then glue each of the 4 corners onto the dovetailed ends. If the joints are cut perfectly then no clamp will be needed:



Make sure to let the glue set completely before cutting the remaining dovetail joints because you will be cutting into the first joint. I glued these up yesterday and will be cutting the remaining joints this afternoon. If all goes well I may get the box assembled today also.
 
#14 ·
Cutting The Remaining Dovetails

I didn't quite get the box assembled on Sunday but I was close.

Next step after gluing the corners is to cut the remaining half blind dovetail joints. I thought I was going to have to do a second setup on my jig to cut these like I had to on my Spalted Mango Box but I didn't. On this box I'm reversing the joints end for end rather than doing a mirror image. Half blind dovetails are actually always reversed end for end like this when cut on an Omnijig and probobly on most other jigs too. It's just not usually apparant becuase they are usually cut symmetrical.

After cutting the dovetails I cut a groove on the inside of all 4 pieces to hold the bottom. For the bottom I resawed a piece of solid Canary wood to match the rest of the box. Plywood would have worked fine also but I much prefer solid woods.

Anyways, here's the pieces all ready to sand and assemble plus a shot of the corner of the box dry fitted together:





After dry fitting the complete box to make sure everything fit correctly, I sanded all the interioir sides and finished with a couple coats of shellac to seal it and prevent glue spots on the interior of the box. Next weekend I'll be assembling the box and beginning work on the feet and top.
 
#15 ·
I wish I could get my dovetails to come out that good. I hacve tried a couple of times to use my Porter cable Jig and to no luck or the lack of my skill to follow directions they came out horible and to loose. Guess I just need to take more time and not get fristrated. Yours look great however and this is a really nice tutorial. Thanks for everything.
 
#19 ·
Assembling the box and Starting the top

Everything about the double dovetail joint is complete. I hope it was cear enough for folks to make their own. Feel free to bug me with questions if you didn't follow. In summary, it's just a bunch of half blind joints using a corner piece with the grain perpendicular to the sides. From here on out it's just another box but I'll continue to post shots as I go.

Yesterday I lightly sanded the shellac that I previously applied to the inside surfaces of all pieces. Then glued the parts together. After letting that dry overnight I rough sanded the outsides of the box with a belt sander to get all the joints flush. Here's the box ready for a top and maybe feet:



Next up is building the top. It's kind of hard to describe what I'm doing so here's a couple of photos of the pieces that will comprise the top and should provide a rough idea of what it will look like:





And here's the top glued up. I hope I got enough clamps on it:

 
#24 ·
The End

The box is almost done. First thing I did today was cut the top to fit. I inititially cut it the same size as the box but decided to cut it a bit smaller so that the corners would show through which I thought gave it a nicer look. I also rabbited the under side of the top a bit to hold it in place. I generallly like lift off lids better than hinged lids for a couple of reasons: I think the metal of a hinge can distract from the beauty of the wood, and I'm too lazy to go buy the hinges.

Second thing I did was to get the box rough sanded to 100 grit. I need to go a couple more levels finer before it will be ready to finish. I almost got that done today but my dinner was getting cold…

Tommorrow I'll complete the sanding and start applying the finish. I'll be finishing it with just several coats of shellac and wax. I used to always finish with oil and a top coat of lacquer. When I set up my own shop I quickly decided that spraying lacquer in my garage next to my furnace was asking for trouble so I switched to water based polyurethanes. I like that for table tops becasue of its' durability but it's slow to dry making it difficult to work with in a small shop since I don't have a dust free finish room. And for small projects like this box it's a real pain to have to clean the spray gun. I tried using sheallac for the first time last year and it's become my favorite finish for most projects, espeically small ones. It's not as durable as a lot of finishes but it drys fast so there is little problem with dust setteling on it and I can apply alot of coats in a short time. There is also no risk of oily rags burning my shop down. It's a natural and even edible product (after it dries), and it's really easy to repair since every coat partially disolves the previous one.

Anyways, here's a couple of photos of the box. The next photos will be of the finished box and posted as a project which I'll try to get done tommorrow. I hope people have found this usefull and I'm looking forward to seeing someone use my technique for double dovetails in a project of their own.



 
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