Wednesday, February 1, 2012

Fitting the Legs




After countless hours of chopping and paring, testing and tweaking, I finally got one of the legs to fit into the top of my workbench.

The next three should go a little more quickly because I learned something very important: trust my layout lines.

Rather than sneaking up on the lines and testing the fit of these very heavy boards along the way, I'm going to cut right to them.

Because these legs will need to be removed on occasion, I left a sliver of a gap between the tenons and mortises. I also rounded over the sharp corners of the front of the dovetail slot. Otherwise, they're too fragile and would chip.

The joint slides together easily. This being winter with low humidity, I expect that they'll be a little tighter when the weather gets warmer. Nothing a little paraffin wax...or more paring...can't handle.

When all the legs are fitted, I'll trim the tops so they're flush with the benchtop.


This is a more difficult build than I had expected but it's a great learning experience.

And that's what it's all about after all.

28 comments:

The Fluffy Woodworker said...

It is looking great I have been following your blogs for awhile now and you have inspired me to move forward in my own woodworking. The Bench looks great and I can't wait to see it finished.

Marilyn in Seattle said...

Really nice! So how are you hands feeling after all that? Are they sore at all? Just curious.

PR said...

That's some really impressive work you're doing! I have a stupid question if you don't mind my asking it... Why do these benches have this strange mortise/tenon and "dovetail" joint? Why not just a simple mortise and tenon joint? Life would be much simpler that way.

Brian said...

I had the same question about the Ruobo benches - why the extreme angle on the outside dovetailed through tenon for the leg? And for that matter, why the dovetail at all? I live in France and have seen benches made that way, but have also seen old benches with a single or double through-tenon. Maybe I am slow, but it seems kind of a fussy joint to cut, and in my admittedly limited experience, unique to this style of bench (I've never seen the joint in furniture, for instance) so there must be a reason for it.

Jonathan Szczepanski said...

Looks great Kari. The tennon popping through the top is so well fitted, that it doesn't even look like a through-tennon. It looks like an off-cut just sitting on your benchtop. Really well done.

Jonathan
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mokusakusensei--woods teacher said...

Nice job Kari!

Frontier Carpenter said...

Your bench is looking good!

vlad jucan said...

Beautifull work! I like your benchtop!one piece?

Rob said...

I'm another curious as to the reason for that unusual joint. Was it a Roubo 'trademark', so it has to be done this way for historical accuracy, or is there a technical advantage?
Sure looks pretty, though, and your craftsmanship is fantastic!

Kari Hultman said...

Thank you, Fluffy Woodworker. :o)

Marilyn, the gloves prevent my hands from being the least bit tired. They're pretty thick/padded.

PR, that's not a stupid question at all. The bench design and odd exposed joinery is from an 18th-century book on woodworking written by Andre Roubo. Chris Schwarz built this bench and wrote about it in his second workbench book. I believe he surmised that the dovetail helps prevent the bench from wracking. And it seems like it would keep it locked in place (from shifting back and forth as you plane) better than one or two tenons. I just think it looks cool and I love a challenge. :o)

Brian, that is an extreme angle (mine is 45ยบ) and all I can say is, when I sketched the angle, a regular dovetail angle looked just plain wrong. I'm guessing the more extreme angle works better at locking the bench in place and keeps it from shifting. It is definitely a fussy joint and probably unnecessary, especially if you use jigs and cut one or two regular tenons with precision power tools. Maybe because the ones made in the 18th-century had to be cut with hand tools, the dovetail made it more stable. So you have seen benches with this design? I would LOVE to see some examples. If you know of any online, please let me know.

Jonathan, thanks. I hope the other three turn out okay. Fingers crossed.

Thanks, McKay and Frontier Carpenter!

Vlad, the benchtop will be in two pieces. This is one half and it measures 2.875" x 9.875" x 60". The two pieces will butt against each other but will not be glued so I can take them apart more easily.

Kari Hultman said...

Rob, I'll dig around to see if I can find a better explanation for the joint other than what I wrote above. I chose to use it because I like the look of it and I like the challenge.

Nick said...

I was wondering about the steepness of the angle too. When I did mine, I laid it out first with a more common 1:7 or 1:8, then decided it didn't look right, and just made an arbitrary angle with the gauge until it looked about right, then stuck with that. I'm trying to determine what advantages going all the way to 45 might give, any insight?

FWIW, I read 3-4 workbench books, including Chris Schwarz first one before building mine, and while It may be an erroneous memory, I think the rational for the dovetail tenon was in one of them (may be worth a call to Chris to chime in). I'll try and find the reference, but it may just be a phantom memory. (Perhaps I'm remembering a good reason for it when none was given, because, like Kari, I liked the look of it, and loved the challenge)

Nice Work Kari, I wish mine had turned out as tidy as that!

Mansfield Fine Furniture - Nick said...

I was wondering about the steepness of the angle too. When I did mine, I laid it out first with a more common 1:7 or 1:8, then decided it didn't look right, and just made an arbitrary angle with the gauge until it looked about right, then stuck with that. I'm trying to determine what advantages going all the way to 45 might give, any insight?

FWIW, I read 3-4 workbench books, including Chris Schwarz first one before building mine, and while It may be an erroneous memory, I think the rational for the dovetail tenon was in one of them (may be worth a call to Chris to chime in). I'll try and find the reference, but it may just be a phantom memory. (Perhaps I'm remembering a good reason for it when none was given, because, like Kari, I liked the look of it, and loved the challenge)

Nice Work Kari, I wish mine had turned out as tidy as that!

Mansfield Fine Furniture - Nick said...

whoops, sorry for the double post, feel free to delete the redundant one.

Aaron said...

Regarding the leg joint, I've heard Christopher Schwarz give a talk about the design. Dyami has some great videos here: http://www.youtube.com/playlist?list=PL23F5C0391E4205BF

From what I recall, you want a double tenon for strength and seasonal movement. Converting the front tenon to the open dovetail socket is for ease of construction - it's much easier to saw away the material in the socket than to drill and chisel out the mortise that is embedded in the top.

Mansfield Fine Furniture - Nick said...

Yup, Aaron is correct: see Dyami's video of Chris Schwarz's explanation of the sliding dovetail(around the 6 minute mark) http://bit.ly/wJWI5y

Anonymous said...

Great work on the first leg, Kari.
I noticed that your top board is only about 10" wide, so you must have decided to cut your mortises first, before gluing up the complete top - for ease of handling. Good planning. The complete top will weigh a ton and would have been tough to handle in the different positions as you pared away and did the test fitting. Keep up the great work!
Frank Eastman

mwh said...

The joint looks great; what I've come to know as vintage Village Carpenter.

I was curious about your "sliver of gap". Are you concerned that this bit of looseness will make your bench susceptible to racking?

This is not merely an academic question. I'm preparing to make a simplified Roubo bench (a la one of Schwarz's many published variations of this bench). It will have a single (rectilinear) non-through tenon. I'm really skeptical of my ability to chop and fit a tight mortise (I' don't have a good track record here). I'd like to just drawbore the tenons without glue, in case I ever move I can disassemble it to get it out of my basement.

The sum of all this is my concern that the slop in my joint will make my bench susceptible to racking. So I'm curious about your feeling on the effect of the "sliver of gap". Do you think the double tenon or the dovetail portion is critical to avoiding this?

Brian said...

Have to get out to get the girls from school. But here's a link to a well used and old one with the double/dovetailed joint

http://www.leboncoin.fr/bricolage/282156241.htm?ca=7_s

here's a single

http://www.leboncoin.fr/decoration/282102461.htm?ca=7_s

I'll have another look this evening. But if you are in work avoidance mode, as I am right now.

You can go to ebay.fr, or leboncoin.fr, and then the search term is "etabli ancien"

The one at the inlaws was made maybe fourty years ago by an old blind carpenter. Single through tenons, but not for a professional woodworker.

Brian said...

Here's another one with your joint.

http://www.leboncoin.fr/collection/279530193.htm?ca=7_s

I have seen a number of various designs in junk and antique shops too, but never thought to take photos.

Cheers, Brian

Kari Hultman said...

Nik and Aaron, thanks for the link to Dyami's video. Chris said it took him an hour to cut the mortise. Wow! Mine took, well....a lot longer. He's right that the dovetail's mortise does not take as long as the tenon's mortise.

Frank, that is half of the top. You are correct. I do not plan to glue the two halves together, however, so that I'll be able to lift them. I know I wouldn't be able to lift the two halves at the same time. Also, it's easier to fit two legs into a board than four as it's being taken apart and assembled for transport.

Mwh, I'm not concerned about the looseness of the joint. I believe that when it's assembled it will be solid. If it's not, I can always glue veneer onto the loose areas and pare them to fit. You could do the same with your tenons if they're loose. I would think that a double tenon or tenon/dovetail would have an affect the looseness of a joint. Chances are your loose areas will be in different spots on each so they would cancel each other out. In your case, though, the veneer will help fix any loose areas. I wouldn't worry about it.

Brian, thank you for the links! I have never before seen this joint on an antique. Very cool. I went on ebay and spent some time looking through them. I found more just googling the French term.

Brian said...

Kari, one of the things I like about your blog is that you don't pretend or imply that it is quick or easy to do good work, for most of us anyway.

MWH, if I might make a suggestion, I just finished a new bench, and also wanted it to be transportable in case I moved. I chose more of a Nicholson approach. The legs are two mortise and tenon R frames. Then the front skirt/plank with the holes for holdfasts is a 4" x 10" construction lumber plank, and the back skirt a 4"x4" piece. I cut 1.5" deep rabbets into the two skirts, and then used carriage bolts and lag screws to join them to the legs. The two stretchers down low were done the same way in the 4x4 stock. I then used three more of the 4X10 planks doweled but not glued together for the top and used lag screws to join the top to the two skirts and the top of the frames. All the bolts and screws were countersunk, and the holes will be filled with plugs. There is a leg vice on one end and a plank hook bolted to the other.

So all the racking forces will be taken by the big rabbets, which are quick and easy to cut. I just made the money cuts with a hand saw and then kerfed and chiseled out the waste with a circular saw and a big chisel. It is not as pretty as the Ruobos like Kari is making. But it is solid as a rock, easy to take apart, very versatile with the Nicholson-style front skirt, and it came in at less than 10 hours of work, and maybe $80, as I scavenged the hardware for the leg vise hardware from a cheap bench that wasn't enough any more. Very similar to but much more massive than the one Bob over at Logan Cabinet Shoppe made.

So anyway, just my two cents. Have fun with your bench.

mwh said...

Thanks for the advice, Brian. Do you have a picture of your bench somewhere online?

Jeff Branch said...

I am showing your blog post to my 21 year old daughter in hopes some of your awesome work will rub off on her.

Brian said...

MWH

Oh man, sounds like I am going to have to go out and clean up the shop in the morning :-) But I should have taken photos while I was building it anyway.

McGlynn On Making said...

Looks great Kari! Hopefully I'll be doing this soon, my legs have been drying for about 4 weeks now.

I'm at a dovetail class this weekend with Jim Tolpin, and I'm realizing that (for me anyway) dovetails are all about being able to saw accurately to my layout lines. I suspect that holds true for most joinery.

Joe

Charles said...

Kari..On one of your responses you mentioned you were not glueing the two top boards together for ease of mobility. Question are you going to spline or t&g them to keep them aligned and together?
Your doing a g job keep it up
Charles

Kari Hultman said...

Thanks for posting all the information, Brian.

Jeff, that's great that you're encouraging your daughter to get into woodworking!

Joe, you nailed it—careful layout and sawing is everything. Hope your class with Jim Tolpin was fun and educational.

Charles, I posted a write-up about this right after this post. Thanks for the question.