# ANGLED Sliding Dovetails.



## sudhana (May 24, 2007)

OK. So I am a professional woodworker and this is really the first time in several years I've had to ask for technical advice, but I really am stumped on this one. Here's the situation:

I want to build a show piece for some craft fairs this summer, its a bookshelf with shelves meeting the sides of the carcass at various angles. I know that with some fussing around I could join the shelves with biscuits, but since this is fine furniture, I'd really rather do dovetails. Does anyone have a special technique for doing sliding dovetails on an angle like this?


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## JonJ (Nov 20, 2007)

OK, I'm NOT a proffessional woodworker, and I've done very few dovetails so hopefully someone else will have something more/better to add… I had to do some on a project, (last couple photos are of dovetails) 
http://lumberjocks.com/JonJ/blog/7717 
I think the same situation you are describing. I made an acetate template of the the dovetail fingers, then marked both sides of the angled end- then kept watching both sides constantly as I was cutting to make sure I was keeping everything on track. It was a lot of "eyeballing"...probably not the best teqnique, but it was the only way I could figure out how to do it. the photos show some excess past ends, but they cleaned up OK.


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## sudhana (May 24, 2007)

Hey Jon,
I think my situation is a little different since I'm trying to make sliding dovetials rather than end to end, but so you know i think you could benefit from making a table saw jig. It will help you cut the tails evenly and if you have a dado blade it can help remove waste from between the pins.


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## rhett (May 11, 2008)

I am unsure if you are talking about a straight angle or a compound angle. I believe you are asking about a compound angle since your works speaks of the ability to figure out a straight dovetail on angle. Try to wrap your head around this worded picture of a very complex joint. The dovetail "pin" on the end of the board for a compound angle will be asymetrical. The pins angle will be laid out from a square line AWAY from the board coplaner to the mating angle In theory this line would be perpendicular to the floor the piece will be sitting on. Hope that makes sense. Probably a reason you haven't seen it anywhere.


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## JimmyNate (Mar 24, 2009)

I"m seeing somthing different than rhett…so perhaps clarify your description. I see horizontal shelves mounted on bookcase sides that are not perfectly vertical. An A frame for example.

I've never done it but I think i would build a jig for each angle to hold the shelf near vertical on the router table. Clamp the shelf to the angle jig, push it up against the fence and go. 2 jigs per angle would get tedious though…I hope you find a better way


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## JonJ (Nov 20, 2007)

err- sorry, I looked up what a sliding dovetail is. As for my situation, one of the pieces was seven ft long. It seems it would have to go through the saw on it's end? My ceilings aren't that tall…..


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## rhett (May 11, 2008)

I believe even a horizontal shelf sliding into an A-frame side would need to have an asymetrical pin. Not only for asthetics but if you can imagine an angled pin hanging from a 3/4" board, you don't have much there. Not to mention that once you come off that board with the pin angled, you will have alot of endgrain in that joint.


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## Waldschrat (Dec 29, 2008)

You are going to have a difficult time cutting the dovetail not the groove it fits in… technically if you want to execute a dovetail that is not perpendicular with the material your joining, the angle of the dovetail (or sliding dovetail) has to be chaned as well so that the grain does not break… does that make sence to you (I hope I explained this properly) More than likely you will have to make one side less steep of an angle to do this. I would draw it out on a piece of paper 1:1 so you have a better idea of what you are looking at. As to cuttin the joint… I think you might end up doing it by hand, Which is not so bad if it is only one piece. The groove is easily cut with a gents saw, or jap. saw and using guide blocks probably ripped down on a table saw to the angle that you need and clamped across the piece. Then cut to your depth and using a chisel and a groove plane get the waste out.

If you need a drawing perhaps I could provide you with one, assuming I have understood your dilema in the first place.


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## sudhana (May 24, 2007)

thanks all for the advice. Here is the sketch up drawing of the project. If anyone has some experience cutting a sliding dovetail by hand I'd appreciate your imput.

SKETCH UP DRAWING


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## grizzman (May 10, 2009)

holy cow adam…your going for a major build i think…good luck…i hope you can figure it out…


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## rhett (May 11, 2008)

You have had me thinking about this for the majority of the day. If I were going to tackle a piece like this, I would cut stopped dados and grooves for all the intersecting boards. If you leave say 3/4" you can cut your asymetrical dovetails on this face and not have the worry of sliding all these complex angles together. I do not think this would compromise the actual structural strength of your bookcase and this would give you the high end look you want without having to worry about gaps down the depth of the boards. Keep us posted. I love the Chinese cracked ice detail and have only seen it in fret work so this is a refreshing use of the idea. Cool design!


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## rcs47 (Oct 31, 2009)

Adam,

I'd seen your post earlier today, gone out to take a few pictures and write down a few things. Now, I finally log back in and see what you meant by angled sliding dovetails. It seems like a jig similar to the one I show below with wedges on the router face should work to give you the angled groove. Or, you could make the jig using angled/wedged material, allowing you to use your router without anything attached to your router plate.

To cut the angled pins, you will need to build a fence for your router table that will be 90 degrees from the angle you just cut. The hard part is getting the fit. You will make one pass, then slid the fence to the other side of the bit, then cut the other side of the pin. It will make it hard to sneak up on the fit.

==

I use a router and jig for sliding dovetails. The jig is a simple setup, using the router plate as the guide. Because I use ½" shank dovetail bits to reduce the flex during the routing of the groove, I used a ½" bit to trim the jig to fit the router.



As you can see, I attached two fences together, leaving one adjustable with carriage bolts/wing nuts. Clamp the jig to your finished shelf line (not edge of the dovetail cut), put your shelf into the jig, slide the other side tight to the shelf and tighten the wing nuts.



Now if you want a tapered sliding dovetail, you can set it at this point by moving one side in by the desired amount.

I drop the bit to the material surface, set the depth, and you're good to go. Multiple passes and your groove is cut for the specific shelf.



Note - I'm using dovetail bits that have a maximum cutter diameter of ½". This way you will not cut a groove beyond your shelf edge. With the ½" shank bits, I think this is the minimum shelf thickness this jig will allow. I've using it with 4/4 red oak without any problems.



I use the same bit in my router table with a fence extension to cut the matching tail on the shelves. I set it a hair shallower (exact measurement here) than I cut the groove. I run test pieces along with the shelves. For the tapered side, it seems that you could cut a wedge, tape it to the shelf, and cut the tapered pin.

Of course, if you want a deep groove, you will need to hog out some of the material first.

I hope this helps.

Doug


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## TopamaxSurvivor (May 2, 2008)

I'm no expert or fine furniture maker, but I have cut dovetails on compound angles a few times just of the fun of it. On that piece, I would dovetail one side of the dado in most cases. The ones that are nearly square, I would do a normal sliding dovetail. I think you will find the radical angles with dovetail cuts on both sides to be very odd looking.


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## Waldschrat (Dec 29, 2008)

Actually, if you build your shelves and cut the angles how you put them on the sketchup then I can see you have already layed them out properly and thought this through.

The jig shown above will not help you though because of the necessary assymetical layout of the dovetail. unless you have the specific angle cutter bit you need, (which I doubt exists). Although the jig shown above is how I normally do a grove to fit the dovetail when I make them.

Cutting by hand should be easy enough, just rip down a piece of stock that matches the angle you need and use a saw, with out a back to cut the groove. draw out where the groove must be with pencil aline your guide and clamp it down and cut it out, then do the other side, but this has another angle so be careful… then after the groove is cut out and waste removed, do the dovetail, same thing, use a guide, clamp it to then end of the board and cut, then to cut the shoulder you will need another guide ripped to the angle that the shelf meets the side of the cabinet.

There is something that you might have overlooked, to make a proper sliding dovetail you should leave around a 1mm of air between the dovetail bottom and the groove… I guess what I am trying to say make the groove 1mm deeper, and when you cut the dovetail leave side that you see without air and the rest you can not see with this air, this allows for movement of wood so if it fits tight, like it should, it does not push the dovetail out and make a gap where the shoulder of the dovetail meets the side of the cabinet. But if you look at from the front you can not see the air/gap.


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## North40 (Oct 17, 2007)

There's a jig for making raised panels on a tablesaw (stick with me here, this really does apply). The jig holds the workpiece at an angle, and that angle is adjustable with a curved slot and a wingnut - sort of like the adjustable angle on a circular saw base. If I was taking on your project, I think I would make a modified version of that jig for my router table.

There are also tenoning jigs which allow you to cut tenons at angles. I don't think they are big enough to hold a shelf, but you might be able to build a bigger one based on the same concept.


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