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 (http://bloodsweatsawdust.com/2015/01/04/2015-roubo-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?

[Brian Holcombe]

The dovetail joints are really cool, that is one of my favorite parts of the Roubo bench.

It's very practical in use if you want the leg to remain flush with the front of the bench.

[ian maybury]

Hi Curt. Sorry, just saw yours now. I'm not an authority in that i'm just starting my own bench build - but i'd be cautious about using a simple lap joint in place of the dovetail where the outer face of the leg passes up through the top. My rationale is just that it's very easy for a strip of wood to bow a little, and if it bowed outwards (and if used glue wetting the inner face might be enough to create some tendency to do this) there would be nothing to mechanically hold it in place. Each joint is composed of three facets each having the grain at 90 deg to each other - so if glued it might or might not hold up long term. The dovetail if well fitted would presumably be pretty effective to mechanically hold it in. It also provides extra sidewards location of the top.

The Benchcrafted split Roubo is probably the design most commonly built these days using crosswise high level rails/stretchers. It's probably not be a bad place to look for inspiration.

Not 100% sure what you have in mind re. the splines, presume it's to let them into a slot in the top surface of the above cross rails, and to cut mating crosswise slot(s) in the the lower surfaces of the halves of the split top. The BC design instead relies on a single closely fitted blind tenon at the top of each leg (which lets the legs into the top) to locate the tops. Even if you use the dovetails it seems unlikely that you will want to leave these out anyway, so maybe you already have the required sidewards location and don't need the splines? The BC bench uses lag bolts up through the cross rails to hold the top down, which seem simple and solid - but splines if used might get in the way of these. Gluing solid wood splines into the bottom of the top wouldn't be good anyway given the likely seasonal movement caused by the differing grain directions.

There's a potential issue that needs consideration if using a BC-like arrangement, or a variant - where the outer edges of the tops are fixed by tight fitting tenons relative to the outer faces of the legs inside and out, and a high cross rail is also fitted. Seasonal movement will result in the top(s) changing width by a significant amount, so that unless provision is made to accommodate this damage will probably be done. The trad Roubo gets around the problem by using no upper cross rails (the legs tilt out of vertical and very slightly rack/splay the lower rail joints to accommmodate the movement), while the BC design accommodates it in the gap for the tool rack that fits between the halves of the tops. (they ask that the rack be fitted leaving whatever potentially fairly significant clearance is likely to be required - as determined by the dimensions/moisture content/likely environment/wood species etc from the tables)

The BC split Roubo could probably also with suitable dimensional adjustments be modified to use the traditional exposed dovetail, and a second inner tenon in each leg too - fixing the tops to the legs presents no problem since movement is accommodated in the centre gap as above.

The other option would be to use a one piece top, tightly fit the vise/near side leg tenons in the top, but leave enough slop in the back pair to accommodate the movement - although in this case the rear edge of the top will move in and out a little relative to the vertical face of the rear legs.

Another variation on the exposed dovetail leg joint is shown in the Roubo book - the drawing of the German Cabinet maker's Bench shows the socket receiving the exposed dovetail at the top of the leg stopped some distance under the top surface of the bench top. I'm not too sure how that's meant to work though, since as the top varies in thickness with seasonal movement it will (since the lower surface of the top is resting on the shoulder of the dovetail) presumably open and close the joint where the upper end of the dovetail buts against the receiving socket in the top. Alternatively the top could rest on the upper end of the dovetail/top line of the joint, and some clearance be allowed for movement between the shoulders and the bottom surface of the top. Maybe this was regarded as acceptable, or maybe i'm missing something...

My best guess (since so many of these benches have been built) is that while differing joint layouts have been used, all (presuming correct design) seem to work pretty well as people don't seem to be running into trouble...

[Brian Holcombe]

How about rising dovetails and a stretcher. :D

[ken hatch]

I've built a number of benches, some out of construction grade wood, some out of hardwood. As I've posted before I think the through dovetail/tenon while it fits the classic design as shown in Roubo's book introduces problems that are unnecessary without adding strength or preventing racking and I do not care how many hours a day you use the bench. I also prefer a split top for several reasons, seasonal movement, keeping the face flush with the front legs, and ease of build to name a few. I'm not an engineer and if I were one I doubt I would test the strength difference between the increased surface area of a through dovetail/tenon vs. a housed tenon draw bored or pegged with double 12mm or 19mm oak pegs. If there is a difference I expect the housed and pegged tenon would be stronger and less prone to racking. It's a mechanical joint vs.increased surface area...you pays your money and you take your chances, it is obvious which one I pick.

From an aesthetic view, the classic configuration can be attractive but whatever, it kinda depends on why you build the bench.

As always with everything wood YMMV.

[ian maybury]

I probably wasn't clear Brian (trying just to figure the pros and cons of some diffrent layouts), but as yourself i was suggesting the dovetails are one option with high rails/stretchers (blind tenons are another) - but that they need a split top, loose tenons at the back or some other arrangement to accommodate movement.

Based on a similar logic to Ken's and as earlier in the thread I'm planning cross rails/high stretchers in my own build (and will probably for multiple reasons split the top, but could yet go one piece), and agree that while the through dovetail looks great that it doesn't seem to add anything much structurally. (other than a continuous leg face through the vise clamping area - which may not be of much practical benefit) I could yet be tempted to incorporate them, but it'd be purely for show and so it's unlikely.

I have a sneaking feeling the dovetail joint might originally have been used on a stretcherless version of the Roubo where the dovetails and long tenon kept a very thick cantilevered leg vertical in an equally thick top, but didn't have to accommodate movement - it seems less likely that they relied on racking the joints in lower stretchers (maybe they floated at one end?) to accommodate movement. (or maybe they did - it seems to work OK anyway)

It seems like it doesn't matter what arrangement is thought of for the joint - there's always some potential (but minor) downside...

[Warren Mickley]

There are some weird and fanciful ideas in this thread. There are maybe a dozen benches illustrated in Andre Roubo's three volume work. There are some variations among these benches, but the top is a single plank of hardwood, bark side down, and the legs are tenoned into the top. There are no cross bearers or stretchers directly beneath the top.

From my experience there is no problem with an exposed tenon.

[Derek Cohen]

The legs of my base are 5" x 3" Jarrah. I had planned to have a 2" blind tenon into a 3 1/2" thick oak. As it was, I increased the height of the bench by adding to the shoulders of the tenons, and this reduced their length to 1".

http://www.inthewoodshop.com/ShopMadeTools/DodgedaBullet_html_m1634618c.jpg

The bench top dropped onto the base, and with a wiggle and a jiggle, the tenons dropped into the mortices. Rock solid.

http://www.inthewoodshop.com/ShopMadeTools/OhSoclose_html_m481b1ef1.jpg



I did pin the top, but it really was not necessary with the mass involved. The moral of the story is that much of the joinery we see is likely to be overkill. I have used this bench now for three years and there has not been a hint of anything but solid.

Regards from Perth

Derek

[Patrick Harper]

Derek, I've thought about leaving the tenons loose and seeing how things worked out. I might just do it. If I run into issues, I can always draw-bore the top to the legs.

Did you assemble your base before mortising the top, or the other way round?

[Derek Cohen]

Patrick, I built them alongside one another. I did have a bench to use. That one had been around for 18 years.

The bench was morticed to receive the legs, and the mortice and tenons for the front and rear stretchers were completed. Below is the dry fit.


http://www.inthewoodshop.com/ShopMadeTools/BuildingaBench5_html_m58f1fc9e.jpg

The top was actually completed first. The parts of the base were assembled, and then the top was flipped over and placed on the base.

There is a record of the build here: http://www.inthewoodshop.com/ShopMadeTools/index.html

Regards from Perth

Derek

[ken hatch]

Derek,

I agree, with the mass of a 100mmX600mmX2500mm slab of hardwood setting on top of and joined by housed mortises and tenons to a two to three hundred lb. base, there is not much chance of movement with or with out pegs. I peg mine mostly just because I peg most M/T joints. I expect it is overkill.

ken

[ian maybury]

I guess in one sense the whole point of these benches is overkill!

All due respect Warren, but that was said - that through tenons (actually tenon and dovetail) are fine with no high stretcher.

You clearly have chosen a personal route (e.g. prefer to be guided solely by Roubo's text), and to diss some aproaches as 'weird and fanciful' - but the fact is that there are other variations on the theme in common and it seems successful use. What's more nobody on this thread is arguing 'this is the only way to do it', just that some designs may not be feasible, and that even the various successful ones have pros and cons. It's been about trying to understand what some of these pros and cons are.

Derek's blind tenon based approach is one that has been successful (it was broadly the approach taken by Chris Schwarz with his original Roubo bench too), as is the more traditional through tenon and dovetail variant CS has been building more recently. The split top high rail/stretcher approach used in the Benchcrafted design is another.

One point about the latter is that by tying the upper ends of the legs together it dictates a requirement for some arrangement (other than simply allowing the legs to splay) to accommodate the in an extreme case approaching 1/2in of wood movement in a full width 24in beech top depending on the conditions and starting state - such as the split top and gap between the halves that it uses. It's very purposely done that way, and in the clear knowledge that the gap is required, and must accommodate the movement. It delivers benefit heowever in terms of ease of build, disassemblability, transportability, and the option to incorporate a tool rack. Which may be of no interest to some, but that's fine - they are free to consider other designs.

The basic i've been trying to communicate is that even the trad Roubo arrangement has some pros and cons, as do all of the others (even presuming they are properly engineered) - but none of these pros and cons are show stoppers...

[Brian Holcombe]

I'm ok with my rising dovetails being labeled as fanciful, they are.

[Steve Voigt]

…You clearly have chosen a personal route (e.g. prefer to be guided solely by Roubo's text), and to diss some aproaches as 'weird and fanciful' - but the fact is that there are other variations on the theme in common and it seems successful use. What's more nobody on this thread is arguing 'this is the only way to do it', just that some designs may not be feasible, and that even the various successful ones have pros and cons. It's been about trying to understand what some of these pros and cons are.

…

The basic i've been trying to communicate is that even the trad Roubo arrangement has some pros and cons, as do all of the others (even presuming they are properly engineered)...

As Warren said, there is quite a bit of variation in the benches that Roubo illustrated, though none use stretchers. So, it is not a question of "only one way," but rather of definite limits on how many ways.

I agree that some of the ideas here are weird and fanciful, or maybe just plain silly. What I'm perplexed by is how you feel qualified to write about the "pros and cons" of the through-dovetail vs. other approaches, when by your own admission you haven't built one of these benches or even used one for any length of time. You can write 50 paragraphs of silver-tongued speculation, but it's really not worth anything unless backed up by personal experience.

My own experience is that I built a Roubo bench that is mostly traditional, but has a few "improvements" based on my (at the time) uninformed speculations about what would work better. I like my bench a lot, but the improvements are the only part I regret. If I build another bench in 15 or 20 years, I'll get rid of the improvements.

[Curt Putnam]

Steve, what is it that you no longer like (the improvements)?

[Curt Putnam]

I'm ok with my rising dovetails being labeled as fanciful, they are.
Brian, I'm not sure what you mean by rising dovetail????

[Brian Holcombe]

http://www.popularwoodworking.com/wp-content/uploads/38-39_1111_PWM_RisingDovetails_Page_2_Image_0004.jpg

[Curt Putnam]

Ian - "Not 100% sure what you have in mind re. the splines, presume it's to let them into a slot in the top surface of the above cross rails, and to cut mating crosswise slot(s) in the the lower surfaces of the halves of the split top. The BC design instead relies on a single closely fitted blind tenon at the top of each leg (which lets the legs into the top) to locate the tops. Even if you use the dovetails it seems unlikely that you will want to leave these out anyway, so maybe you already have the required sidewards location and don't need the splines? The BC bench uses lag bolts up through the cross rails to hold the top down, which seem simple and solid - but splines if used might get in the way of these. Gluing solid wood splines into the bottom of the top wouldn't be good anyway given the likely seasonal movement caused by the differing grain directions."

The idea of a spline appeals to me because of it's simplicity. I don't see that it needs to be glued but could be to the transverse stretcher. A dovetail at the leg vise and blind tenons for the other three legs would seem to be sufficient while allowing for seasonal expansion into the center gap. If needed, a few lags with wiggle room to hold the tops down.

I'm also toying with the idea of a non-symmetric top: maybe 15" for the front side and 9" or 10" for the backside.

If, indeed, these thoughts are wild and fanciful, 'tis best to find out before the build starts.

[Curt Putnam]

Ah, I see, said the blind man to his deaf wife as picked up his hammer and saw.

[ian maybury]

:) Tee hee. I'd missed the meaning of the 'rising' part in your mention of a dovetail Brian. It'd be the ultimate in 'looks right' joinery in the situation though!

I've a sneaking feeling i'm still not getting what you mean on the splines Curt, but I'm hesitant to extend the discussion in the circumstances.

I made no attempt to set myself up on a pedestal Steve, the opposite in fact - and was doing my level best to respond to a direct question from Curt. By pointing to how the same issues had ben handled on the established designs.

Anybody else had they the inclination was welcome to constructively come in on. As did Derek, Brian and Ken….

[Steve Voigt]

Steve, what is it that you no longer like (the improvements)?

The main thing was using a face vise as an end vise, rather than a tail or wagon vise, and as a consequence placing the dog holes about 4.5" from the edge. I distinctly remember reading Chris Schwarz's advice to place the dog holes closer, and ignoring it (mostly for economic reasons; I already had the vise and couldn't afford another at the time). It's not the end of the world, but I've regretted that decision many times.

On the other hand, I remember shelving my preconceptions about leg vises and building a traditional one with parallel guide, again mostly for economic reasons. I had so many misgivings about using such a seemingly primitive device. But that thing has so vastly outperformed any other vise I've ever used, it's not even funny. I'd like to think that I learned something from those two experiences.

Not that you asked me for any advice, but if I were you I'd be very wary of things like splines and lap joints that aren't found in the literature. I recommend you get Chris Schwarz's first book on benches, or his article in the Sept. 2005 PW, and just do what he did.

[Steve Voigt]

http://www.popularwoodworking.com/wp-content/uploads/38-39_1111_PWM_RisingDovetails_Page_2_Image_0004.jpg

Brian, is that a Japanese joint, or is it of your own design?
Either way, it looks pretty cool.

[Brian Holcombe]

That's not a picture of my work, just one I found online. That being said I've made the joint, I have a model I constructed floating about the shop.

It's a Japanese joint. I've been dying to put it to work, but have yet to come to a project where it is needed.

[Tom M King]

It looks like the impossible staircase, until you see the slope on the back of the tenon. Thanks for posting that. I have a use for it after seeing it.

[Curt Putnam]

The main thing was using a face vise as an end vise, rather than a tail or wagon vise, and as a consequence placing the dog holes about 4.5" from the edge. I distinctly remember reading Chris Schwarz's advice to place the dog holes closer, and ignoring it (mostly for economic reasons; I already had the vise and couldn't afford another at the time). It's not the end of the world, but I've regretted that decision many times.

Not that you asked me for any advice, but if I were you I'd be very wary of things like splines and lap joints that aren't found in the literature. I recommend you get Chris Schwarz's first book on benches, or his article in the Sept. 2005 PW, and just do what he did.
Interesting: I am planning on using a face vise (a 7" Wilton) in the tail position. 7" on a 12" section means 2.5" unsupported on each side for the wood chop. I'm expecting to use a rack preventer and get enough pressure to hold stuff at the front edge. So far, all I've ever done with a tail vise is to keep stuff from wiggling around due to lack of skill on my part.

I hear your advise. Same as what CS put in his book. Already got talked out of a lap joint. However, I see the spline as a loose tenon. Making dados is a lot easier than chopping blind mortises.

[Pat Barry]

I'm ok with my rising dovetails being labeled as fanciful, they are.
They certainly are fanciful. I wonder if that's all they are though. What do you feel are the advantages?

[Brian Holcombe]

Over the dovetails original to the bench? I doubt that there are any. The interesting part of the rising dovetail is that from the outside it appears to be impossible.

The downside is that it the way it must be installed, which is that it cant go straight on like a tenon, it must 'rise'.

[Patrick Harper]

This really got off topic, but that's fine. I'm glad everyone's talking.

Fitting the legs to the top before completing the base went well. My biggest concern was maintaining alignment while marking out the mortise locations. The legs move around a bit if you aren't careful. The legs are fit, now it's on to the stretchers.

http://bloodsweatsawdust.com/2015/04/01/roubo-workbench-build-chopping-mortises-by-hand/

[ken hatch]

Ian - "Not 100% sure what you have in mind re. the splines, presume it's to let them into a slot in the top surface of the above cross rails, and to cut mating crosswise slot(s) in the the lower surfaces of the halves of the split top. The BC design instead relies on a single closely fitted blind tenon at the top of each leg (which lets the legs into the top) to locate the tops. Even if you use the dovetails it seems unlikely that you will want to leave these out anyway, so maybe you already have the required sidewards location and don't need the splines? The BC bench uses lag bolts up through the cross rails to hold the top down, which seem simple and solid - but splines if used might get in the way of these. Gluing solid wood splines into the bottom of the top wouldn't be good anyway given the likely seasonal movement caused by the differing grain directions."

The idea of a spline appeals to me because of it's simplicity. I don't see that it needs to be glued but could be to the transverse stretcher. A dovetail at the leg vise and blind tenons for the other three legs would seem to be sufficient while allowing for seasonal expansion into the center gap. If needed, a few lags with wiggle room to hold the tops down.

I'm also toying with the idea of a non-symmetric top: maybe 15" for the front side and 9" or 10" for the backside.

If, indeed, these thoughts are wild and fanciful, 'tis best to find out before the build starts.


Curt,

My split top bench is asymmetrical, one of the best changes over the previous bench which was also a split top but symmetrical. The original slab sizes were 190mm for the narrow side and 370mm for the wide side, that's a little over 7" and 14" for those still stuck in the foot, yard, and stone world. In the photo I've added a 50mm wide apron to the bench making the wide side about 420 mm or about 16" wide. I have no regrets and in fact the bench I'm helping a friend with is also asymmetrical.

http://i257.photobucket.com/albums/hh222/VTXAZ/benchApronFinished_zps7cf7fe0d.jpg

ken

[mike mcilroy]

I built the base and marked for the mortises on the underside of the top by turning the top upside down on my old bench then inverting the base on top of that. Way too difficult for one person to do easily. By the time I got the base inverted on the top I realized I was not going to move it off and on to test fit the mortises. I ended up drilling and squaring the mortises by keeping the base on the top and just sliding it enough to work the mortise. The test fit required spreader clamps beside each leg to move the base again. Then when everything was good and then drawbored I had to get someone to help flip it over. If you don't have a helper readily available for frequent moving of heavy parts the new trick might be the way to go.

[Patrick Harper]

Mike, that was one of my biggest concerns. Sliding the entire base several times, while test fitting the tenons would be a real pain. I'm glad I fitted the tenons before completing the base. All four legs are fitted and I am working on the stretchers.

[mike mcilroy]

Patrick
Mine got done but definitely wish I had the time machine. Your way would have been easier. Hope you enjoy the bench I love mine. I put leg vises on both ends and I started the sliding vise in the middle although right now its just a sliding piece of wood.
it slides real purdy though!:D

[Patrick Harper]

Mike,

You have leg vises at both ends? What vise hardware did you use? I'm using the BenchCrafted classic.

The base is complete, and I just finished laminating the chop. Once I get the vise hardware installed, I can mount the base and I'll pretty much be done.