Attaching Breadboard to a tabletop

[KentAndy]

I am in the process of building a coffee table with hopefully breadboard at the two ends. My question is about how to attach the breadboard. I know that you can use m and joints but...

Is it possible to attach them using a sliding dovetail?

Many thanks,

Andy

 

[mouppe]

Yes, I suppose so but it would be much more difficult. I have used dominos in the past.

 

[RogerP]

It certainly is and well fitted but left unglued with just one central fixing expansion/contraction of the table top is provided for.

 

[custard]

Yes, a sliding dovetail will work very well, but only if the table is pretty flat or you have a way of ensuring the joint itself is cut flat. Any twist or cupping, no matter how slight, will cause the dovetail to jam as you try to fit it. The traditional way of cutting the male part of the dovetail is with a little wooden jig that you use to guide your chisel at the correct angle, the problem with this method is that you tend to make the jig fairly short and cut the joint in sections, which means you can follow any undulations in the table top. You just need to be aware of this and check as you proceed that you won't fall into this trap. The other thing to remember is that dovetails, unlike tenons, don't provide much support against leverage, and people often sit on the ends of tables so the leverage can be pretty extreme. The solution is to make the breadboard ends a bit narrower with a sliding dovetail than you would with mortice and tenons.

Everyone always talks about the need to allow the table to expand and contract across the grain, but there's another factor with breadboard ends that's almost as important, at least in my opinion. There's nothing worse than seeing a gap between the breadboard end and the table, so that you see a ***** of light or even the floor right through. And in time, as the wood moves, that's almost inevitable unless you have a small spline or haunch running the full width...or you use a sliding dovetail.

Good luck.

 

[Beau]

You could use biscuits/dominos near the middle and dovetail keys on the ends. A lot easier to get together than a full on sliding dovetail.

 

[Racers]

A sliding dovetail would be very difficult to do over a long run and very tricky to get right.
Mortice and tenon has been used for years because it works and is easy to do.
Have a look at https://www.youtube.com/user/doucetteandwolfe they have some very good videos and show breadboard ends being made.

Pete

 

[woodbrains]

Hello,

Why do you want to use a sliding dovetail in this instance? I can't see a situation where a sliding dovetail BBE would be an advantage, but the difficulties in making them are high. As custard says, they only project a short way into the BBE, so leverage on the ends is a problem. Keeping the BBE narrow to reduce leverage, somewhat defeats its function, as a reasonable width is required to keep the tabletop flat, the BBE's function. A snug enough fitting sliding dovetail will be hard to fit, the friction involved is great, make it sloppy and again, it's function of keeping the top flat is compromised. And how do you glue it? Just at the centre to keep it together but still allow seasonal movement of the table top, but how can a sliding dovetail be glued only at the centre? The glue will be smeared along half of the joint at least, during assembly. And appearance wise, once the top shrinks or expands with seasonal movement, there will be an ugly dovetail shaped protrusion of depression on the BBE. Multiple mortice and tenons, joined by a stub tenon and draw bored into elongated holes and glue on the centre M&T is beat all round IMO.

Mike.

 

[paulrockliffe]

I've no experience of keeping tops flat but was wondering whether you could achieve this by drilling through each length of timber in two or three places and inserting a piece of steel threaded rod. Obviously not going all the way through the two side pieces? You could then use nuts and washers to pull the top tight together, before attaching the outside pieces. If you didn't glue it you could tighten it as the wood shrinks too perhaps.

If that works (?) you could do whatever you wanted with the BBE as you don't need it to keep the board flat. For a sliding dovetail you could remove the middle section to make it easy to get on if you could fashion a hidden fixing in the middle to stop the BBE from cupping. A pocket-hole screw from underneath might work.

 

[Racers]

The movement of the wood has to go somewhere, it would crush the fibres around the nuts when it expands and then leave it loose when it contracts.
You can't restrain the movement you have to work with it, have a look at this thread to see what constrained wood can do how-can-a-tabletop-with-a-split-45-degree-joint-be-repaired-t91248.html

Breadboard ends have been used you centurys because they work, every thing else has been tried and they failed.

Pete

 

[whiskywill]

drilling through each length of timber in two or three places and inserting a piece of steel threaded rod.

That would be a truss rod, then. https://www.google.co.uk/search?q=truss ... 00&bih=766

 

[KentAndy]

Thanks for all of your replies.

I wanted to use dovetail because of how it looks more than anything. When I started I was going to pocket hole but was concerned about expansion.

 

[dzj]

Traditionally, sliding dovetails are sometimes used with battens under the tabletop.
I've never seen them as a method of affixing breadboard ends.

 

[RogerP]

Thanks for all of your replies.

I wanted to use dovetail because of how it looks more than anything.............

Here's the method actually used if you'd like to see the way it looks.

http://home.comcast.net/~davidyoh/toy_box.htm

 

[KentAndy]

Thanks for all of your replies.

I wanted to use dovetail because of how it looks more than anything.............

Here's the method actually used if you'd like to see the way it looks.

http://home.comcast.net/~davidyoh/toy_box.htm

Looks fantastic. Would you be able to tell me how you did it?

 

[RogerP]

Thanks for all of your replies.

I wanted to use dovetail because of how it looks more than anything.............

Here's the method actually used if you'd like to see the way it looks.

http://home.comcast.net/~davidyoh/toy_box.htm

Looks fantastic. Would you be able to tell me how you did it?

I didn't do it! Just found the site. As others have said it probably would not be the best way for your table,

 

[Racers]

Just because it has been done doesn't mean its a good idea.

Pete

 

[RogerP]

Just because it has been done doesn't mean its a good idea.

Pete

Quite.