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I'm in the planning stages of building a simple workbench, and I'm a bit stuck on the bench top itself.

One of my goals for this bench is to be able to disassemble it as much as possible, to make it easier to get into and out of places where having a bench would be handy. Most of the plans I've seen involve laminating boards together to create the bench surface, which I'd like to avoid as it becomes a rather large block that can't further disassembled.

Would it be feasible to use breadboard ends to hold together a bench top made of 2x4s set on end?

It would look something like this (the picture shows it at 1 ft wide, this may end up being wider): Breadboad Ends

The weight of the bench top itself would be resting on another couple of 2x4s sitting inside what's basically a large dado cut in the bottom, anchored with through mortise: Benchtop support cutaway

This should trap all but the outer two 2x4s, which would be captured by the breadboard ends.

Is this a viable way to hold together a workbench top?

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  • I have a response to your question below. Additionally, in my opinion your bench is overly complicated with those leg dados and through tenons - and what looks like 8 legs? You can do it for fun, but if you are aiming for a simple bench, this is not it. Sure a Roubo has those through tenons, but it's usually a thick hardwood top with no stretchers or apron... but you have both a thick top and stretchers set into dados. I'm not saying it wouldn't work, but it's just a lot of work for no real advantage. – aaron Oct 18 '18 at 12:33
  • Also, a laminated top would not be my choice for a simple/knockdown bench. I would suggest looking at English/Nicholson designs. – aaron Oct 18 '18 at 12:33
  • If you're stuck on this general design, you could make it work by splitting the laminated top. You'd still need to fasted the members composing the two laminated halves, but everything else could stay the same, with the benefit of not needing the breadboard ends at all. – aaron Oct 18 '18 at 12:36
  • @aaron WRT the leg design, I'll probably be asking another question about that soon as it's a bit out of scope for this :) – Morgen Oct 18 '18 at 14:45
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The answer is sort of yes, but there's a lot more to it than that as there's not enough allowance for wood movement. In short, the breadboard ends can't stretch or compress and they'd really need to in order for this to work properly.

Hidden within normal/conventional breadboard ends (when done correctly) is extra room to allow the main field of the top to expand and contract as needed — as you can see from the link above, seasonal variations in humidity result in changes to the wood's moisture content, leading to changes in width. The wetter the wood the wider the top, the drier the wood the narrower the top.

You can minimise this seasonal variation in certain ways, by selecting boards with quarter-sawn or rift-sawn grain* and by working in woods that move less than others. But unfortunately 2x material is not generally wood that moves relatively little.

So I think you need to ditch the idea of the breadboard ends.

What to do instead
Essentially all you're looking to do here is hold the two outermost boards down so they can't fall off or be lifted out of place when the table is in use, and there are other ways of doing this, all simpler in fact. And even better news, the simplest involves no extra work.

All you need to do is fix four flat expansion plates, or figure-eight fasteners, to the underside of two of the 2x4s which are then screwed to the outside two boards. This will securely hold them down while allowing them to move in or out as needed.

*This doesn't mean only how the wood was cut, it can just mean that the grain (seen from the ends) is vertical or nearly so. To put it another way, you orient the tangential grain vertically.

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  • If you're trying the keep the front edge of the top coplanar with the legs (a useful feature on a workbench), then you should affix the front edge with something rigid and use the flexible fastener (figure 8s, etc) on the back side. My suggestion above to use a split top would keep both front and back edges coplanar on both sides, leaving the flexible space in the center of the bench. – aaron Oct 18 '18 at 14:32
  • Also, very important here, is that if you don't fasten the individual boards in the laminated top together, when they expand and contract, the contraction will leave gaps between the boards. – aaron Oct 18 '18 at 14:33
  • I'd like to avoid metal hardware, as it has an unfortunate tendency to get lost in a move. Would replacing the two outer 2x4s with a single 4x4 and ditching the breadboard ends work instead? – Morgen Oct 18 '18 at 15:00
  • @aaron unless the gaps are large (more than 1/16"), I'm not particularly concerned about it. Pretty would be nice, but it's not a driving motivation – Morgen Oct 18 '18 at 15:03
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    @Morgen I understand not wanting to lose metal hardware but they can stay screwed to the cross-wise 2x4s. But even if you did uninstall completely and lose one they can be something like 25c a piece, plus due to minimum pack sizes you'd probably have spares already. Re. gaps, they shouldn't be a big deal — individually about 1/16" sounds about right and they'd be easily closed up anyway with a hip check or a couple of smacks from a mallet (esp. if you wax the channels and 2x4 surfaces). – Graphus Oct 19 '18 at 14:27
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A breadboard end is meant to keep a panel flat, not prevent seasonal contraction/expansion. A breadboard is typically joined with a fixed (ie, glued) mortise and tenon ("M&T") in the middle, and maybe another two M&Ts on either side. These two tenons are pinned, not glued, and the pins go into elongated holes. The elongated holes allow for the seasonal movement. Note that the M&Ts could be replaced by a single long, but deep, tongue and groove. google "breadboard end pinned" for some quick examples.

In your case I hesitate to even call it a breadboard - the M&Ts fastening your breadboard to the "panel" (workbench top) are not joined int he conventional way. I would expect the center of your panel to bulge out in the expansion season. You're looking at a problem, whatever happens. You still need something to keep the laminated top together, and that is going to be either glue or mechanical fasteners (eg, screws). You can use a breadboard or other means (eg, cleats) to keep it flat.

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  • The intent is not to prevent seasonal contraction/expansion, but rather to keep the bench top flat and the two outer 2x4s from falling off and hitting my foot :) It's not really visible the pictures, but the inner construction is pretty standard breadboard - with the exception that the outer M&Ts go all the way through rather than just protruding more than the rest of the tongue, and that it's not pinned. The bulk of the top is kept together by the tenon coming up from the legs, not by the breadboard – Morgen Oct 18 '18 at 14:51
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    Ok I see. In that case I would really just go with cleats along the bottom. You'd use a similar approach with screwing those in - the clearance holes in the cleat should be elongated as you move away from the center line of the benchtop. – aaron Oct 18 '18 at 16:44

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