How to make this angled sliding DT joint?

[atgcpaul]

I want to make this angled sliding dovetail joint. It's not to scale, but the pieces will be almost 2" wide (this view) and 3" wide (side view). Actually, from the top, it will look like a half lap, and you'll only see the DT from underneath--so a stopped sliding DT.

I've never cut a sliding DT but could figure it out if the intersecting pieces were 90deg to each other, but I'm having trouble wrapping my head around this one. I haven't determined the angle yet, but it will be close to what I've depicted.

Thanks,
Paul

[Joel H.]

That my friend is a problem.  Normal (90 deg) sliding DTs are simple with a handheld router and a straightedge.  In your case you would need a router whose base tilts.  Don't think you could it on a router table.  Maybe John's horizontal router setup would accommodate it?  Only John can answer that.

Good luck,  

Joel

[Aram]

Handsaws, chisels, angle guides and a router plane. Maybe. Looks hard.

[FS7]

I did something like this once and it came out pretty well. Here's what I did:

The middle piece (bottom for me, since I only did one side) is a straight dovetail socket. No problems there.

The pin itself is a separate piece, which is also a straight dovetail. Mill a thin piece of stock using a router table (or table saw, if it's an odd angle) to make a trapezoid shaped piece. Mine was thicker than I need and I planed it until it fit perfectly. This you can then fasten directly to the top and bottom pieces after you cut them to the angle you want. With solid stock, you can put some glue on it and either pin it or screw it on. I used screws and glue since I had enough wood area to do it and the countersunk screws wouldn't show.

I hope this makes sense.

[JGrout]

I actually see it possible on a router table  but it will take two angled fixtures 

Point one: The tapered part needs to be in the horizontal (female cut) of the set up that is the easiest one to make the taper in as the cut is flat and parallel to the faces.

Point two: the male section the "vertical" in your sketch has to be cut at the angle before you cut the dovetailed pin thereby giving you a starting reference point. By making one beveled rip cut in a piece of say 8/4 at the correct angle and about 12" long you have the two pieces required to cut the tails by affixing them to the router fence then it is just a matter of setting the joint cut depth on each side. One side will push the vertical member outward and the other inward 

Joe

[jteneyck]

You can make the female dovetails in the normal manner using your router and a straight edge or template to guide it.  The male dovetails could be easily be cut with my horizontal router mortiser, using the tiliting X-Table.  I was cutting mortises here, but the concept is the same:







To do this you would first cut of the end of your parts at the angle needed, using your tablesaw, mitersaw, etc.  Then you would mount them on the horizontal router mortiser at the angle you cut them off at, I think.  In any case, the end that you cut off needs to end up perpendicular to the router bit.  Once it's set up, you would cut those dovetails in one pass on each side.  

Without the horizontal router mortiser you could do it by making a T-type jig, with another piece screwed to the vertical leg of the T to give the same angle it would be on the router mortiser.  Your workpiece would be clamped to that piece, with the cut end up against the bottom of the horizontal leg.  The top plate would have two slots milled into it to fit a guide bushing, tuned so that the dovetail bit cuts each side of your dovetail.  Alternatively, you could just use one slot and then use a shim behind the workpiece to move it from one cut to the other.  I like that one better, actually, because then you can tune the angled fence for one side of the cut, and your shim would define the width of the dovetail end and could be easily planed/sanded to fit your female dovetail.  

John

[atgcpaul]

Yes, a horizontal router table seems like the way to go for the male DT.  When I'm cutting the DT shoulder on the "inside" face, won't the piece be trapped between the bit and table?  Maybe if I cut most of that away first on the table saw, it won't be as much of an issue?

[JGrout]

your concern is why I suggested using a standard router table 

it takes the trapped cut out of the equation

[Steve N]

Don't take this wrong, but you are not a graphic artist.


Like this? In term of case work, this is the common use of a sliding DT, angled makes it even more rare, or maybe obscure.





Male is done on a router table, Female is best hand cut, or with a tilt base table like John showed you, or a hand held router with a tilt base. I would hand saw it. Using a small block of wood with the proper angles, clamped onto the piece gives a nice guide to rest the saw blade on. All you need to do is make straight arm movements. Depth of the cut must be pre-marked. Care to make sure you don't get carried away, and saw past your line.

What you write as a half lap, and your picture appears you do want to lap the joint. To that my question is why then does it need to slide? Or be a DT? What is the intended use?

[atgcpaul]

Don't take this wrong, but you are not a graphic artist.

Ha Ha!  Understatement of the year!

What you write as a half lap, and your picture appears you do want to lap the joint. To that my question is why then does it need to slide? Or be a DT? What is the intended use?

I want to make this coffee table (You've got to scroll about half way down the page).  http://www.archiexpo.com/prod/bark/produ...02726.html

I have a rectangular piece of glass so that's why the cross pieces won't meet at a 90deg angle.  I want to be able to pack it flat for storage and transport so that's why I don't want to assemble it as half laps.  The idea is to glue one whole loop together and that would have the female DT slots.  The other loop would actually be in two pieces and have the male DTs.  Come assembly time, the two halves would slip upwards into the slots.  From above it would look like a half lap joint.  From below I'd route a recess to receive a metal plate to prevent them from sliding out.

One alternate idea I have is to join them with half laps, but leave the bottom stretcher of one loop unglued.  I plan on joining the loops with Dominoes.  The bottom stretcher could be screwed to its uprights from underneath.  The only reason why I don't want to do this is for the "feel".  I know if I were to see this in a showroom, the first thing I'd do is go check out the half lap joint.  Then I'd run my hands across the joints where the stretchers meet the uprights.  Personally, I would not want to feel any bump or divot in the transition.  If I leave the stretcher "loose", I think over time I would feel it.

Yes, I have a little OCD.

Paul