Number of pins(and spacing) for breadboard ends?

[Ken Platt]

Folks -

I'm breadboarding the ends of a 45 inch wide table, maple. This wood has been kind of flaky so far in terms of movement, so I'm wanting the breadboards to be nice and sturdy. Most plans I see use just three pins for breadboards, but I'm wondering if a tabletop of this width should have more. I'm undecided on the aesthetics except that 4 didn't look right, so if I went more than 3 I'd use 5, and space them such that the outer pairs were closer to each other than to the middle pin, like this:

X___X___________________X __________________X____X

Thoughts, suggestions, experiences? Anyone every had a pin fail on a breadboard and allow the breadboard to come off? Thanks -

Ken

[Mike Barney Sr]

I have never liked the idea of breadboarding. On a 45" width, depending on the wood of course, you will experience a change in dimension of up to 1/4", possibly more, between summer and winter months. It's just the nature of wood. When needing a large panel I start from rough, cutting the straight board out of the crooked one. Taking a few weeks to dimension my lumber little by little, letting the freshly exposed wood acclimate to my shop, I glue up the panel taking care to orient the grain correctly. With care the panel will stay very flat. Breadboarding has always appeared to me to be a way of forcing wood to do what you want. I don't like to do that. I feel it is best to: (read my signature)

[Lee Schierer]

If I were going to breadboard the end of a wide glue up I would make the joint a sliding dovetail and pin it in the center in one or two places a few inches apart. The wood in the table field could then do what ever it wanted to do without destroying the table.

[Pat Barry]

I like Lee's suggestion but it sounds like it might be very tough to accomplish - not only making the good fitting sliding dovetail that long, but also getting it to fit together. If it worked it would be very good solution but if it binds up then it will restrict the wood movement too much and likely causing cracking in the summer to winter transistion. I just saw the Woodwrights Shop episode this weekend where he was making a breadboard end for a small piece and he used a breadboard design (borrowed from Thomas Jefferson) that had a few thru tenons built into it. I thought this was a cool idea and might help on a very wide breadboard edge nicely. It would provide additional material to do the pinning process. Obvious, but the tight fitting pins must be in the middle, not on the ends.

[George Bregar]

First, breadboard ends are designed to keep panels flat, but they are also design elements. They hide end grain. For my slant top desk top I put them in...glued the breadboard in the middle, pinned the wide tenon at the ends. Now it's only about half as wide as the OP's top but it has stayed flat and no issues with the top over ten years of dramatic humidity changes that we have here in WI. The holes in the tenon that the pins go through are slotted to accommodate movement of the top...and the mortise cut into the breadboard is also wider for the same purpose. You are not "fighting the wood" as has been suggested. This is working with wood movement and is much easier than a sliding dovetail. Here is a pic...not the best but you can see the pins...I also duplicated the breadboard ends on the filing cabinet drawer fronts. They too are flat and no issues...and I really like the look

[Jeff Bartley]

Ken,
If it were my table build I'd use 5 tenons: one in the center, one close to each edge, and one between the center and each edge.
---X------X------X------X------X---
The most important thing to keep in mind is that the wood will move; like mike said, "up to 1/4". So only use glue in the center mortise and widen the outer four mortises to allow for movement. As well you'll want to ovalize the peg-holes in the tenons on the outer four so that those can also move with the seasons. Another technique that can be applied here is the 'spring' the joint between the breadboard end and the table top. You basically put a bow (like 1/32 to 1/16) into the breadboard end so that when the center tenon is pegged it holds the ends tight against the table top.
I also like to leave a 3/8 to 1/2 rib between the tenons to everything in alignment.
Hope this helps.

[NICK BARBOZA]

I think George nailed it here.
I recently completed this piece for a friend and did a 'different' layout for the pins in the breadboards. As long as you glue only in the center, slot holes in the tenon and elongate mortises for movement, pin layout should not matter.
Good luck,
NWB

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[Kent A Bathurst]

Anyone drawbore the pins?

[George Bregar]

Anyone drawbore the pins? Mine were. Been a while so I can't remember what the offset was.

[keith micinski]

I went a different way. I used a floating tenon and I glued the tenon into the breadboard end. Then I glued the tenon in the middle of the piece and let the end's float free. My piece is 26 inches wide and it has already shrunk in enough to feel the tenons protruding a little. The fact that this is happening tells me I allowed for enough wood shrinkage movement. Now we just have to wait for the summer to see if I allowed for enough expansion.