How do I non-permanently attach the top of a workbench to legs?

[Minh Tran]

I would like the ability to remove the benchtop (comes in handy if I ever move to another apartment). The bench is a work in progress, though I don't have complete plans for it (I'm undecided on what the base should look like). It's made from 2x4's stacked side by side with the 4-inch faces against each other. Traditionally, I've seen it assembled using mortise/tenon with glue for permanent assembly. I'm ok with using lag bolts but is there any way to install them so they won't protude from the benchtop?

[Mike Cherry]

On my bench, also made with construction grade lumber, I have a bearer that sits on top of the front and rear legs. This bearer is screwed into the stretcher that connects the legs together and the top pf the legs. Think of it like a spacer between the leg assembly and the benchtop. I then screwed through this bearer into the bottom of the benchtop. Totally reversible should I want to disassemble it. I can take a picture if you need it.

[Minh Tran]

A picture would be terrific! Thanks.

[Conrad Fiore]

If you build your base with top rails, simply drill through and counterbore to accept hex head bolts with the CB large enough to accept a socket to tighten. Lay the top of the bench upside down and place the base in the correct alignment. Mark the centers of the drilled hole in the top.
Purchase brass threaded inserts to be installed in the underside of the bench top. Install the inserts according to the instructions and thru bolt the base to the top.

[Phil Stone]

I worried about this a great deal when designing and building my bench. But it turned out the mass of the top, combined with the very large mortise and tenons for the legs (this is a design similar to Schwarz's Roubo, but with blind, rather than through tenons) make any kind of fastener completely unnecessary. It doesn't budge under work load, but can still be lifted off to move the bench.

[Phil Mueller]

I did the same as Phil above. The weight of the top just holds it in place...no need for fasteners at all. As Phil may have done as well, I chamfered the tenon ends which makes placement into the mortises easy.

[Phil Stone]

I did the same as Phil above. The weight of the top just holds it in place...no need for fasteners at all. As Phil may have done as well, I chamfered the tenon ends which makes placement into the mortises easy.

Yup. Keeps them from chipping, too. I'll add that the rear mortises are slightly oversized to allow movement of the top, and the front mortises are tight (but not too tight). Those front mortises keep the top from budging.

[glenn bradley]

I have large dowel about 5" long with one end rounded off like a bullet. They are driven up from underneath through holes in the legs into a receiving hole on the underside of the bench.

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They extend about 1-1/2" into the bottom of the bench slab.

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There is enough hanging out to grab and pull on if I need to remove the top.

[Minh Tran]

Brilliant! I'll take the M&T route for this one (since I need some practice cutting/chiseling). I love your solution though - definitely something to consider in the future.

[Phil Mueller]

Minh, for what it's worth, here are a few photos of what I did.

Assembled the base, and cut the tenons on the legs. Put the base upside down on the bench top, aligned it, and marked for the mortises.

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I then chopped the mortises (truth be told, drilled out most first and then finished with a chisel). The base is right side up...you can see the tenons are chamfered.

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Dry fit. The block sitting on the bench top next to the leg is a duplicate of the tenons with depth indicated. That way I could accuratly cut the mortises without constantly moving the heavy base to test the fit.

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Good luck!

Sorry for the sideways photos...these were iphone taken...never could get these right side up.