Constructing workbench base - join legs to stretchers or dry fit to top first

[Jessica Pierce-LaRose]

I'm getting to the point where I'll need to start working on the base of my planned bench soon - It's a four inch thick 5'x20" top and the plan is to surface some 8/4 stock, and laminated two of those for each leg. (Perhaps I should go with three?) Given that the legs are a little smaller, I'll probably be going with a drawbored tenon joint from the legs to the top rather than a "roubo" style sliding joint.

My query is, would you proceed by dryfitting the mortise/tenon joint from the legs to the top, and then marking the stretchers off the leg assembly, remove the legs and make the stretchers, or by making the whole base assembly and then making all four mortises at once? I see Chris Schwarz used the first method with his "18th Century" Roubo, (the giant cherry slab one) and the second method with his Holtzapffel bench in the "Workbench Design Book".

The big issue I can see with the first method is removing the dry fit legs from the their mortises - this is obviously easier with the Roubo style joint, as you can pound it back out from the through-joinery. I suppose I could do through tenons on this joint, and then wedge them in addition/instead of the drawbores.

The advantage seems to be that I'd only have to fit each leg to it's own mortise, and then by marking the stretchers to fit, I could compensate for any for any misalignment, as opposed to trying to get four mortises to fit perfectly - at least, that's the theory and what I've done with success in similar situations (on a much smaller scale)

Or perhaps the best solution is to combine the two methods, and make two-leg assemblies via the small stretchers and and fit two mortises at a time, and then mark the long stretchers off the work. This would make removing the dry fit leg assemblies easier, at least.

Or perhaps I'm overthinking this and should just get back to surfacing lumber.

[Jim Koepke]

Though the joinery looks nice with this type of arrangement, there is a possible problem that was recently pointed out by Chris Schwarz on his blog at PWW.

He did say the wood was a little soft in the area.

My thought is to build a pair of support beams under the bench instead of cutting into any of the bench top. This would allow for easier changes in the future.

I have also thought of having stub tenons on the legs that fit into morices on underside of the top.

jtk

[Jim Matthews]

If you're building trestle style, the top surface is turned face down, and the base is used to mark the connections.

If you're building a Roubo or variant each leg is bulky and difficult to manipulate on it's own. With all four together, it would be unmanageable.
FYI - This is an overly robust mounting method for all but the most passionate chopping and planing duty - two dowel pegs and a couple screws are plenty.

If you make this thing too pretty, will you be able to use it as a tool?

[Federico Mena Quintero]

When I was making my Roubo, I used a story stick to mark the distances between legs. Then I used that stick to size the stretchers, to mark the sliding dovetails on the top, etc.

I had the bright idea of doing a dry fit of parirs of legs to the top, before adding the long stretchers. Removing the legs later to put in the stretchers was a total, complete, and absolute pain in the ass. I guess the leg-to-top joints were tight enough :)

The legs of my bench were done in pine, so either:

- they had enough flexibility that any errors in accuracy were masked by that,

- there was enough play in my joints to let everything fit well in the end

- the story stick really works like magic and everything was accurate enough.

[Rob Fisher]

Though the joinery looks nice with this type of arrangement, there is a possible problem that was recently pointed out by Chris Schwarz on his blog at PWW.He did say the wood was a little soft in the area.If you are referring to the cherry topped bench that Roy Underhill had his way with, then I would say that it was entirely the punky wood and not at all the joinery. That type of joinery is fundamentally sound and fairly simple, although not necessarily simple to make. Chris has another slightly larger Roubo type bench that has a laminated SYP top and he has had no complaints that I have heard. All of that said (or wrote) I agree that a stretcher under the top has its merits. That is how I intend to build my bench because I feel it will be easier for me and my less than developed skills.

[Steve Branam]

I followed Schwarz's instructions when I built my Roubo. It was a bit of a wrestling match to get the completed leg assembly up onto upside-down benchtop to fit things, but I won.

[Michael Peet]

Hey Joshua,

I assembled the base first and then marked the mortise locations on the underside of the top. Like you, I too considered both approaches.

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While bulky to work with, it seemed like less opportunity for error this way. Just make sure everything is square and true, and that it doesn't move while you are marking the locations.

Mike

[Salem Ganzhorn]

I pretty much followed the directions from BenchCrafted. I really like the split-top design. I assembled the base first, marked the top(s) straight off the tenon's and had no problem accurately fitting the mortices. Plus the split is really useful. I use it as a vertical tool tray for chisels awls and other things that may attempt to roll off the bench. Plus having the top split in half makes it a manageable process by one person. But even then those slabs are heavy!!!

Good luck!
Salem

[Carl Beckett]

+1 on the split top. But not sure that is the questionI would assemble the base first and make sure it's square, especially the shoulder where the top will pull down on. Make these level to each other, perfectly. Let the mortise tenon be loose if there is error. Draw bore the top down on the shoulder. Otherwise if the legs aren't square the top will never seat against the tenon shoulder properly

[Joe Fabbri]

I'm consdering some design decisions for my bench right now, and I'm wondering is there any problem with expansion, when running the leg tenons into the top? I mentioned in another posting about an idea I had for making a trestle bench, with a trestle on the top and bottom of the legs, and continuing the leg tenons through the top trestle and into a shallow mortise in the bench top. This way you have a trestle supporting each side on top of the legs, and a way of securing the top to the base. I was told, though, that there might be some issues with expansion of the top.

Also, is there any reason you guys seemed to want to put the base on top of the upside down top in order to mark the mortise locations? Rather than the other way around, putting the base on the ground (provided it's level) and putting the top upright on the base, then marking it from underneath. I'd think that would be easier, wouldn't it, especially if the base is very heavy? Then you could just flip the top over on the base and work from there. I guess it would depend on how heavy the base is.

[Carl Beckett]

These tops are crazy heavy. The base of mine weighs less than the top so easier to do it upside down. But either way would work

[Mike Zilis]

While the base is upside down laying on the underside of the top, it's a good opportunity to lay out, cut and mount some or all of the vice hardware.

[Salem Ganzhorn]

I actually put the tops on the completed legs to mark the mortises. Both top and legs were crazy heavy but the top is in two pieces. This is not how benchcrafted recommends doing it but it is what made sense to me. Just had to make some shims the same height ad the tenons to hold the tops level.
Salem

[Steve Branam]

The top is the heavier of the two, and being a flat piece is a little trickier to manage. The base, as a large rectangular frame, can be rotated by one person. It's worth getting a helper. Once I had completed the mortises, I was able to stand the base up, flip the top, and slide it over to drop on the tenons by myself.

After that, it was too heavy to handle safely by myself. How do I know that? When laying it on its back to finish the planing stop, I couldn't hold onto it, and it fell on my foot. Fortunately, I had put boards on the floor as spacers so I would be able to get my hands under it later. Those kept it from falling the last inch and crushing my foot. Since I was just wearing sneakers, I got a nice bruise out of it and sore foot for a few days. I was literally just an inch from broken foot bones.

Get a helper, or clamp 2x4's to the top as lever arms. Either way, it's still awkward to handle and dangerous.

[Jessica Pierce-LaRose]

Yeah, I think being aware of what you can move safely is an important thing with building these benches. I think I'm going to glue a couple more boards before I call the top done (to add a dog hole strip) and even at only 5' x 20", it's getting to be more than I can handle safely without proper preparation - I can maneuver it around on the saw horses, but lifting it/lowering from the ground is a hassle without being prepared.

Because there's still some joinery, I haven't softened the edges on one side yet, either. Remember to where gloves - freshly jointed edges can be sharp...

[Hans Braul]

I came up with a different approach that worked well for me. I incorporated the laminations of the legs directly into those for the top, and the joinery was created as part of the staged glue-up. I posted a quick summary on this forum:

http://www.sawmillcreek.org/showthread.php?172475-Roubo-Bench-Build&highlight=

(http://www.sawmillcreek.org/showthread.php?172475-Roubo-Bench-Build&highlight=)Here are some additional progress pics of the glue-up process that provide some idea of the technique:

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The assembly was quite easy and although I've never tried making the joints once top and base are assembled, I would guess mine was quicker. Of course, it is crucial that all stock be milled to exactly the same thickness.

Regards
Hans

[Steve Branam]

Nice, Hans!