Split Top Roubo Suggestions

[James Brislawn]

I posted this in the design forum yesterday, but on second glance that forum seems less active and since I will be mainly using the bench for hand tool work and there are a lot of bench threads in this forum I’m moving it here. Also I haven’t posted anything yet, but have got a lot of good advice from the members in this forum from the search function and other people’s questions, haven’t seen this situation come up so felt it warranted a thread.

I’m currently in the process of building a split top Roubo bench a la Benchcrafted design plans. The 2 tops are 3”x12”x72” each. I’ll be installing the benchcrafted tail vise, but will be using a cast iron QR face vise instead of the leg vise. My plan is to have the outside edge of the left leg set in 14” from the left end of the top, and the outside edge of the right leg 17” from the right end of the top to accommodate the vises. This leaves the base 41” wide. I’ve seen several options for adjusting for shorter bench tops (like mine), but most of them advise no overhang on the left which works with the leg vise but not the face vise or eliminating the tail vise which I don’t want to do. My question is will the 41” base profile be an issue on the 72” bench? If it makes a difference, the top is European beech, and the base is Mesquite (crazy hard/dense), the legs are 4”x4”, the long stretchers are 2x4”, the short stretchers are 2”x4” (bottom) and 1”x4” (top). The final bench height will be 34” My plan is to attach the top with 1-1/4” bullet dowels, the long stretchers with BC barrel nuts and the short stretchers will be drawbored and glued with Titebond III. I already have all the wood s4s and cut to rough length, and the tops are already glued up, so I’m hoping not to make any crazy adjustments, but would like some opinions on what adjustments I might need to make since so far I’ve done a ton of research, but have only been woodworking for about 8 months now.

[Chuck Nickerson]

For the last five years I've been working on a 84" split-top Roubo bench with about the same overhangs. There has been no problem.
Look at it this way: you will be sawing, planing, and chiseling. Sawing and planing apply no real downward force. Chiseling can be done over a leg.

[James Brislawn]

Thanks for the response. I think I was right to move the thread here :).

I’m not concerned about the overhangs themselves as they seem pretty standard, there are a few things that are different on this bench that could hypothetically introduce problems, but I’m unsure if they will actually be significant enough to warrant concern.

The main concern I have is with racking force applied to the front left leg over time (years) when planing edges in the vise. I don’t own, nor do I intend to purchase a powered jointer or table saw, and so far this has been the bulk of my planing work so far with the s2s lumber I buy having some pretty ragged edges, and my handsaw ripping skills lacking anything near clean edges as well.

The 3 things where I may be introducing weak points are:

1) The bench is shorter and so the base will be shorter as well (41” in this case, whereas the base on the bench you mentioned would be ~53” if the overhangs were exactly the same)

2) The face vise will be mounted to the left of the leg, rather then on it like with a leg vise, creating additional force due to leverage

3) The bench must be made to knockdown (my shop is in a spare bedroom on a 2nd floor apartment, and would be impossible to remove otherwise) which weakens the connection points of the top to the leg and the long stretchers to the leg, where most of this force will be applied

I am not entirely convinced the sum of these 3 weaknesses pose any real concern, but given the amount of time and money going into this project, I’d like to make damn sure before I go too far. I am not married to the attachment methods per se, they are just what I’ve read to work the best from my research so far. I am even open to going the leg vise route, but as I already have a pretty good face vise (Morgan 10” from TFWW), I’d rather not change it up unless absolutely necessary. If I did that I’d leave the few extra inches I have on the long stretchers and reduce the overhang on the left side.

I’m half worried the entire thing will explode and half thinking it will be totally fine.

[Hasin Haroon]

You'll be perfectly fine. My roubo has a much longer overhang on the right of the base and I'm not at all concerned in use. Also your point no. 2 regarding weakness is actually a strength - a regular cast iron vise isn't levering the top against the leg unlike the leg vise would be, so it wont be applying the twisting force on the top relative to the base.

[ken hatch]

James,

I expect if the base is strong and stable enough the top attachment makes no never mind.

I've build both French benches and Moravian benches, while different base designs both are very sturdy and stable. I've used different means to attach the slab, Pegged M/T on the French bench and loose round (dowel) M/T on the Moravian, I would be comfortable using the loose round M/T on a French bench if the base was stable enough. One advantage of the loose M/T is ease of slab removal. Of course with the French you still have to deal with an overweight/oversized base when you need to move it. Love my Moravian benches.

ken

[James Brislawn]

Thanks for all the reassurance I am now only 10% afraid the whole thing will explode.

Ken, since you’ve used them before, do you have any suggestions for sourcing the dowels for the loose tenons? I’ve heard you don’t want to use the standard commercially produced ones due to grain and inconsistent sizing.

[ken hatch]

Thanks for all the reassurance I am now only 10% afraid the whole thing will explode.

Ken, since you’ve used them before, do you have any suggestions for sourcing the dowels for the loose tenons? I’ve heard you don’t want to use the standard commercially produced ones due to grain and inconsistent sizing.


James,

Nothing wrong with using commercial dowels. Go through to stack and there will be several with straight grain. I find a good set of metric drill bits can work wonders when trying to find the correct sized drill :). Remember most of the world works in metric.

ken

[David Eisenhauer]

My split top slabs are mounted with mortises in the bottoms of the slabs and slightly undersized tennons on the leg tops. I had no desire to ever fight the top(s) installation by myself. I have the slotted screw hole arrangement for the ends of the tops where they cross over the stretchers (BC plan) and have never noticed any movement at all. The beefy base design of the BC plan does not make me believe you should have any issues with putting a vise further out on the end of one slab. I have a face vise mounted on the end of one of my slab ends (the "back side" left end) and it sees lots of use for sawing and planning. My bench is freestanding and allows access to both sides.

[James Brislawn]

Follow up question on the dowels now. Is the suggestion for metric bits due to the fact that the dowels wouldn’t be exactly the right size and so metric gives more options for closer matching? Or are you suggesting the holes be slightly oversized which I imagine would introduce too much play, or undersized and then maybe sand the dowels down to get a tight fit?

I’m fairly committed to the loose M/T since my bench height is based off the combined height of the legs and tops and I don’t really want it shorter. I haven’t found much in the way of instruction on the dowels other than to round them over a bit to allow for easier alignment, and chopping square/rectangular mortises in the leg tops makes me nervous I might split the legs.

[Drake Daggett]

I have the same plans from benchcrafted. I don't see an issue with the dimensions you give. Have at it.
Where'd you get the thick mesquite? Or are you laminating?

[James Brislawn]

There’s a local sawmill here in Tucson called King Mesquite, they have it in even larger sizes, no lamination necessary. I did laminate the tops myself out of 8/4 beech. I sent the owner a cut list and they filled any voids you’d see on mesquite that size and planed it all s4s. I’ll end up smoothing them a bit with my LV LAS, but dimensioning mesquite by hand is a rough job. A worthy test for the new PMV-11 50 degree blade too :). I dropped off the tops after i glued them up and got them mostly flat with my #5-1/2, and had them get them dead on parallel and even thickness. S6S I guess?

[James Brislawn]

Update: Moving forward with the bench build, it’s mounted on a couple sawhorses right now until I build the base, but I’ve marked everything out on the tops and went ahead with drilling the dog holes. Included pictures of all the lumber stacked at the sawmill, progress I made this morning with the dog holes, and the jig I made to drill them. I used the old Starett dividers for spacing, and the jig fence keeps them the same distance from the edge. Not sure why, but the first picture seems to only want to post upside down.
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[ken hatch]

Follow up question on the dowels now. Is the suggestion for metric bits due to the fact that the dowels wouldn’t be exactly the right size and so metric gives more options for closer matching? Or are you suggesting the holes be slightly oversized which I imagine would introduce too much play, or undersized and then maybe sand the dowels down to get a tight fit?

I’m fairly committed to the loose M/T since my bench height is based off the combined height of the legs and tops and I don’t really want it shorter. I haven’t found much in the way of instruction on the dowels other than to round them over a bit to allow for easier alignment, and chopping square/rectangular mortises in the leg tops makes me nervous I might split the legs.

James, sorry my reply got lost in the ozone. Reason for metric is many times the dowels are made to the nearest metric and labeled fractional. Before I use a dowel I test drill both the fractional size to the nearest 1/64" and metric .05mm around the labeled size to find the best fit. More often than not it will be a metric size.

If you are in Tucson, PM me.

ken

[Tom Bender]

Not sure why you want to build it knock down. It will be something like 72" x 28" x 34" right? That will fit thru most doorways and down stairs like a highboy, just need a little more muscle, and maybe a hand truck. Glued up solid is simpler and more robust. I have built two similar to yours. Made the base and flipped it over onto the tops. traced around it and mortised the whole base into the tops about an inch. Glue up and done. Rock solid and never gonna fail.

[James Brislawn]

Haha if only, I worked for a moving company all through high school, not scared of moving heavy things up and down stairs. If it was just stairs that’d be one thing. It’s mainly getting it past the spiral staircase that blocks the hallway. Here’s some pictures of what I’d have to deal with. It was a pain just to get the tops in there. The outside stairs aren’t easy either.
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[John Isgren]

If knock down is needed have you considered a Monrovian style bench?

[ken hatch]

If knock down is needed have you considered a Monrovian style bench?

Thanks, I didn't want to sound like a broken record but even if you don't need "knock-down" the Moravian has many advantages over a Roubo/French bench. The ability to knock down is just the cherry on top. Full disclosure I have two French style benches and three Moravian style benches in my shop and currently building a fourth Moravian. BTW, when talking about knock down, I know by using bench bolts and other means a Roubo can be made to take apart but with a Moravian the bench can be broken down into its seven units is a minute or two and put back together as fast. I think there is a video of Will Myers putting one of his benches together in less than a minute.

ken

[James Brislawn]

The Moravian definitely looks like the better knockdown option. I really only plan to take it apart once when I move out of this apartment though, which honestly probably won’t be for a few years anyways.

I’m too far in to switch things up at this point though, with all my wood cut within a couple inches of final length for the Roubo. if I were to angle the legs like the Moravian my bench would be about 3 inches too low for my height, and the long stretchers would be too short. Also looking through the build, it looks a bit past my skill level at this stage with the angled tusk through tenons. The split top Roubo seems pretty simple (right angles) except for the wagon vise since I’ve already got both slabs finished.

My next step is to start working on the mortise and tenons. I’m pretty confident in my mortising abilities, but not so much in the tenon cutting department. I’ve been putting off the rest of the build while working on some other projects and practicing my sawing skills in the mean time. Will probably get started on the base in earnest here in the next couple weeks.

[ken hatch]

The Moravian definitely looks like the better knockdown option. I really only plan to take it apart once when I move out of this apartment though, which honestly probably won’t be for a few years anyways.

I’m too far in to switch things up at this point though, with all my wood cut within a couple inches of final length for the Roubo. if I were to angle the legs like the Moravian my bench would be about 3 inches too low for my height, and the long stretchers would be too short. Also looking through the build, it looks a bit past my skill level at this stage with the angled tusk through tenons. The split top Roubo seems pretty simple (right angles) except for the wagon vise since I’ve already got both slabs finished.

My next step is to start working on the mortise and tenons. I’m pretty confident in my mortising abilities, but not so much in the tenon cutting department. I’ve been putting off the rest of the build while working on some other projects and practicing my sawing skills in the mean time. Will probably get started on the base in earnest here in the next couple weeks.

James,

I did not post about the Moravian bench until someone else posted mostly because I figured you had already settled in on a Roubo. Like I have posted, I have a couple of Roubo style benches and they have served well and I expect they will continue to do so. That said, any new construction will be a Moravian because of its advantages of cost, ease of build, and of course ease of break down for moving and/or part replacement. Good luck on your build and keep the photos and posts coming as it progresses.

ken

[James Brislawn]

James,

I did not post about the Moravian bench until someone else posted mostly because I figured you had already settled in on a Roubo. Like I have posted, I have a couple of Roubo style benches and they have served well and I expect they will continue to do so. That said, any new construction will be a Moravian because of its advantages of cost, ease of build, and of course ease of break down for moving and/or part replacement. Good luck on your build and keep the photos and posts coming as it progresses.

ken

Yeah, I was mostly answering John’s question of whether I’d considered Moravian or not, which I guess was a no until I was already too far in lol. I didn’t start this thread until the wood was cut, purchased and hanging out in my apartment. Wood aside though, I think the skill requirement is beyond me for the time being anyways.

I saw your build thread and am very aware of your position on the Moravian workbench haha. I’d definitely love to take a look at your stable of benches one of these days. Sorry this weekend didn’t work out, I only saw your PM Monday and I’m only off Saturdays and Tuesdays anyways. It looks like you’re pretty close though, I live downtown right by the art museum.

I think all my initial questions from this thread were answered. Once I get the base going I may update it with build pics and any new questions that arise. I should really get working on it though to clear up some space, finally have my bench at the right height and reclaim the use of my two sawhorses that are currently serving temporary base duties.

[Tom Bussey]

After 4 benches I can honestly say that getting the height right is the most important part of the build. I built a temporary bench and played with the height. I came up with 34 1/2 inches for height for me and my type of woodworking. Now I like to stand on a anti fatigue mat when working at the bench and even that thickness played in the final height. The thickness was around 7/16ths so my actual working heights for me is 34 and a 1/2 inch difference can make a difference after a long day at the bench. I don't know how the jointer got in there but I use the feather boards to square up the actual 4x4s that made up the legs. to hard for me at 72 to keep it against the fence and feed it at the same time.

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