Dovetails in long pieces

[Paddy Roxburgh]

Due to a terrible oil spill in the river Lea the navigation is closed for the next couple of weeks so my dry dock is standing empty, so rather than worrying about how much money this is costing me I've decided to spend the week making some bits of furniture for my house and for my sister's 50th birthday. I'm currently drawing up a large bookshelf for my house, it will be about 8ft tall and will hopefully clear my spare room of all the piles of books that make it unusable. I initially did dovetails on my drawing, but I am at a loss as to how to cut them on such long boards. I am usually comfortable hand cutting them, but I also have a woodrat router jig. I have considered putting the jig 8 ft up a wall in the workshop and standing on scaffold planks, but TBH I reckon it's a recipe for a f c k up. I have also thought about sawing them by hand with the boards horizontal, but I'm not sure how well I could do this. I will probably do some other joinery solution, perhaps rebates and dowels/dominos, but I am curious as to how others have approached this problem. So if you've ever cut dovetails in long boards, how did you do it?

 

[deema]

On a pair of Saw horses with the end hanging over the edge.

 

[Paddy Roxburgh]

On a pair of Saw horses with the end hanging over the edge.

I suppose if I cut the tails in the long boards horizontally then I could cut the pins in the vice, I'm just unsure if I can saw accurately enough with the boards horizontal, suppose I will find out tomorrow.
Paddy

 

[custard]

I am curious as to how others have approached this problem. So if you've ever cut dovetails in long boards, how did you do it?

I've made benches that had solid ends/legs, hand dovetailed to the top. Instead of tails first I did them pins first, which meant the much longer top could be laid flat on the bench for the transfer. You're right, I did find it uncomfortable hand sawing the tails with the board horizontal rather than vertical, and if I'm honest there was a bit of paring involved rather than doing the job "straight off the saw", but it all worked out okay in the end.

Good luck!

 

[MikeG.]

Set a temporary bench up on a footbridge. :lol:

 

[Bm101]

Paddy. I had no idea about the oil spill despite being just up the river from you. Thanks for the heads up. Not sure how I haven't heard of it tbh.
It's probably a mad unworkable idea in reality but could you drop the bottoms of the boards into the dock and strap/clamp them madmax style to the railings/parapet if you have enough drop for 8 foot boards. Maybe.... :? Sometimes the daftest ideas and all that...
Hope all is well generally and things get better soon on the work front fella.
All the best
Chris

 

[Mr T]

Could be a silly idea, but how about a jig to cut them on the band saw supporting the end on a roller stand. Or are you after a hand sawn solution?

 

[Paddy Roxburgh]

Chris (BM101), the oils spill is at Tottenham, according to the CRT operations manager they estimate 30,000 litres!!! Main suspects are Redcorn car breakers and the bus garage, but nobody knows for sure. None of it has come this far North but they have shut the locks at Tottenham and Stonebridge so people don't bring the oil upstream through the locks. The river by us is open but the customers we had booked are all from south of Tottenham lock. Setting the boards so they hang into the dock is not a bad idea, I'll think about that tomorrow.
Other Chris (Mr T), I'm not adverse to using machines. I've never actually cut joints on the bandsaw but I've seen it done on youtube and often wanted to give it a go. I've got a pretty reliable 30" Wadkin bandsaw but only tend to use it for deep rips and cutting curves, maybe this is a good excuse to branch out in my working practices.
Mike, as BM101 pointed out, I kind of have my own bridge at the dock.
Custard, before trying any of the other options I'm going to try an over length board (so I can cut it off) horizontally.
Paddy

 

[MikeG.]

I did a very serious tutorial on this some years ago. This may help:

......

........

 

[MikeG.]

......Mike, as BM101 pointed out, I kind of have my own bridge at the dock.....

Problem solved then. Set up a bench there, with the board hanging vertically down over the edge (or through it, if it is slatted). Cut your tails in the usual way.

 

[MusicMan]

I was puzzled by this thread, thinking what's the issue? Then I realised that that was why I kept my ancient Arcoy Dovetailer. 50th anniversary this year, wedding present from my mates. The long board goes horizontally and you cut downwards.

 

[Just4Fun]

Oddly enough I am currently facing the same problem and have been putting off cutting those joints until I decide the best way to go about it. On my project I have decided to modify the joint to simplify the problem. First I asked myself why I had to go for dovetails at all and came up with 2 reasons: One is that I want to stop the vertical sides of the piece splaying apart, and the second is that I like cutting dovetails. Now the back of my piece will hold the back of the sides together so I only really have to concern myself with the front of the side pieces splaying apart. So really I only need a single dovetail, near the front of the piece. This reduces the work and the scope for a screw-up compared to having dovetails across the full width of the boards. The rest of the width can be a simple rebate in the sides with the top just sitting on (in?) the rebate. Also I may use a half-blind dovetail. This will mean any errors will be hidden on the top of the piece where nobody can see them.

 

[AndyT]

Interesting question. As far as I know, there is no YouTube demo to help - they all assume that you want to join 10" long offcuts.

Frustratingly, I know I have solved the problem. About 35 years ago I made a big mahogany bookcase, with lap dovetails at the top and sliding dovetails at the bottom.

I know I would have cut the tails first. I think I must have laid the boards on the bench, sat on them and sawn down from above. Transferring the marks was probably done with the boards on edge, maybe clamped onto something to hold them square.

Sawing and chiselling the sockets would also have been with the board flat on the bench and me sitting on it.

Whatever I did in those pre-internet days, it worked, though I no longer have the bookcase.

Please post some wip pics for the benefit of the next person contemplating such a build!

 

[Mr T]

Other Chris (Mr T), I'm not adverse to using machines. I've never actually cut joints on the bandsaw but I've seen it done on youtube and often wanted to give it a go. I've got a pretty reliable 30" Wadkin bandsaw but only tend to use it for deep rips and cutting curves, maybe this is a good excuse to branch out in my working practices.

If you make up a simple jig to hold the pieces at the dovetail angle bandsawn dovetails are pretty straight forward. By flipping the board you can get good symmetry.

Chris

 

[MikeG.]

I really don't see the problem in cutting dovetails horizontally on saw horses. What possible difficulty does this throw up?

 

[Knot Competent]

About ten years ago I had to cut some mortice and tenons using a Trend M & T jig, with 6' long rails needing to be put in the jig vertically. I was fortunate, my then workshop had a car inspection pit....

 

[Droogs]

Don't you have a fret saw? If worried about angle etc just make some wood guides for the blade, hot glue them on and saw while the boards are either flat or on edge and horizontal on the bench. Then pare to your line

hth