Roubo Build: Order of Operation

[Patrick Harper]

I'm looking for a few opinions from those who have completed a Roubo build. I'm currently in the middle of my build and have read both of Schwarz's books. In the first workbench book the base is completed before the mortises are made in the top. In the second book, the legs are fitted to the top and the stretchers are marked out and fitted using stop blocks. I like the latter method and would like to think that this is a nice little trick that Chris discovered after writing the first book.

What are the pros and cons of each method?

You can find my build here: Roubo Workbench Build

[ken hatch]

Patrick,

The order I use depends on the top, if it has a split top it is easier to build the base and then fit the slab to the base. The split allows for adjustment to finished width. If building a solid slab then it is easier to fit the base to the slab by fitting the legs and then marking the stretchers. I've done it both ways, prefer building a split slab (for other reasons) and fitting the slabs to the base instead of the other way, but either works.

ken

[Christopher Charles]

Hello Patrick,

Also depends on whether you already have a bench that is useable as a work surface. If you don't have a bench and build the base first, it can be used while building the top. Sounds like you have a bench already, so it doesn't matter as much, esp. as Ken points out, if you are doing a split top.

Good luck and you'll be glad you build a bench.

C

[Patrick Harper]

Thanks for the ideas guys. FYI, I'm building a solid top with stub tenons. Was going to do the whole dovetailed through tenon thing, but decided I needed a better bench soon more than I needed a pretty bench later.

[ken hatch]

Thanks for the ideas guys. FYI, I'm building a solid top with stub tenons. Was going to do the whole dovetailed through tenon thing, but decided I needed a better bench soon more than I needed a pretty bench later.

Patrick,

Smart decision, the only up sides to the through dovetail/tenon is the fact it matches an illustration in an old book and it allows you to show off if it is done well. There are several down sides, starting with exposed end grain on your bench top, different expansion rates and direction between the exposed legs and the slab, and it is harder to maintain the top. A pegged housed tenon has all the strength needed, is a lot less work to build and maintain. Pretty much win win....

ken

[ian maybury]

Must say i can't get my head around the through tenon arrangement anyway. The issue of the top varying seasonally in thickness in both directions doesn't seem very well handled...

[Patrick Harper]

Thanks guys! I figure there has to be a reason our predecessors did it though. I would think a draw-bored stub-tenon would resist racking as much as a through tenon, but what do I know?

[Pat Barry]

I just have the stub tenon on my bench and although it is a solid top, not a split, I haven't seen any issue at all. Mine in fact is so loose as to easily be lifted off, well easy as a ~ hundred pounds is to lift. I don't have any racking. I feel that the racking is a function of the base stability anyway. My top is sitting there but not a structural element in this regard. There are other lateral braces in the base that prevent racking (so far)

[ian maybury]

I'm heading for a tight front and oversize mortise at the back set up to give room for the top to move. Also a high level stretcher under the top. The biggest downside i've found so far with this method (when drawing it up) is that the high level stretcher might get in the way/needs careful fitting in if you use a twin vise or a leg vise with a high mounted screw...

[ken hatch]

Thanks guys! I figure there has to be a reason our predecessors did it though. I would think a draw-bored stub-tenon would resist racking as much as a through tenon, but what do I know?

I work under the assumption to be careful when doing things differently than the old guys, if you can figure out how they did it but.....as always there are buts, sometimes they did things "just because". I think the through dovetail and tenon was one of those "just because".

[James Conrad]

Other than aligning the face of the leg with the bench this type of joint provides a large bearing surface, increases stiffness and resists racking better - often there was no bracing as in a typical table leg construction.

[Christopher Charles]

Indeed, without bolts to tighten when racking forces were applied 9-10 hours / day 6 days a week, any measure to prevent joints from coming loose would make sense. With modern hardware (or other joint options) and 9-10 hours / month if one is luckier than I, not so much need for the through tenons... That said, the dovetails were probably for show

C

[ian maybury]

I guess one benefit of the exposed through dovetail might have been that a leg vise ended up bearing against a single/continuous length of material (the leg) which is also well supported by the top - also that there was no step/transition in the clamping zone behind the vise chop.

For sure if using a blind tenon it might be best as a result to ensure that (a) it's very solid and a tight fit laterally, and (b) that there's no great thickness of the top between the tenon and the edge of the top/the clamping surface of the vice - so that whatever differential movement there might be (minimal?) is minimised. Although of course if the remaining skin of wood outside the outer tenon is minimal, then you might as well eliminate it and run with the traditional exposed dovetail to the side. Except that that creates the previous problem of the differential vertical movement between the top and the leg….

As in the case of the original, it might suggest also that a double tenon makes sense - the outer one while not have great sideways strength might assist the vise function, while the inner (with a decent width between it and the outer) is possibly more concerned with locating the top.

Maybe a though dovetail, with a blind one to the inside might be a compromise? Just playing with it..

The choice between the arrangements seems ultimately down to which of the conflicting benefits you prioritise......

[James Conrad]

End grain of the legs showing through the top was considered a "commoner" bench.

[Curt Putnam]

Ian, what would be your thoughts (split top) about the usefulness of a dovetail vs a simple lap joint? Since a split top needs transverse bearers, the top can rest on a spline that sits in matching dados for top and bottom. That resist longways movement; I'm still debating how to resist widthwise movement. I really want the leg to run through the top for the leg vise situation you just described?