A Hand Built Roubo, and the Education of a Woodworker

[Andy Pedler]

Are you confused by my sawhorse/torsion box set-up, or Hans' bench's legs?

We're all confused by Hans' bench legs. If he really laminates the legs together as shown, then it seems like he has two dovetails on the end, one that wants to slide up through the bench top from below and the other that wants to mate from the front/back.

I'm mechanically declined so I could easily be missing something, but it just doesn't seem like it would work.

Andy - Newark, CA

[anthony wall]

dave as you live in an apartment you will need to consider that you will probably need to move it someday so build it so that it can be fully or at least partialy dismantled to make manageable to move,good luck with the build

[Michael Peet]

I could be wrong, but I understood Hans to mean he was going to build the legs into the top during the lamination process, NOT attach them after the top was fully assembled.

Since all stock is dimensioned exactly the same, I will laminate the legs into the top

Mike

[David Keller NC]

I felt guilty for about a second, but decided it would be ok to use a power drill in this case if I promised myself that I would dig the other 8 with just the chisel.

David - There is substantial evidence from remaining tool marks that wasting the majority of a large mortise with a drill bit and paring the walls square with a chisel was standard practice in the age before the advent of power tools. I've personally seen evidence of this in a circa 1780 timber-frame structure that was taken apart for moving. In many of the mortises, there are the tell-tale imprints of the center spur of a center bit on the bottoms of the mortises.

And honestly, there isn't really much difference in the end result of an electric-powered drill and a brace and bit. It's sort of like a lathe - while many of us have built and used a spring-pole or treadle-powered lathe, a whole lot more of us that are dedicated neanders use electron-powered versions. The end result is almost identical - it is possible to distinguish the interrupted cycle of tool marks on a piece made by the operating characteristics of a spring-pole lathe, but it's exceedingly difficult, even for furniture conservators with a museum's worth of specialized microscopes.

[Carl Beckett]

Re: working to close tolerances. Besides thanking yourself 5 years later after appreciating the quality every time you look at it, its great practice to get it all 'tight'.

By practicing you will build the skills so that you can build fast AND tight. I am always most impressed by those woodworkers that quickly knock out a joint in one pass that fits together perfectly. Its what makes them so efficient.

A fun project, and more fun that you are doing it in a NY apt.....

[Chris Fournier]

I've first saw this thread on Friday and have been thinking about it all weekend. I can't believe you can be doing all this in your living room with just hand tools! I am in the process of building my Roubo bench. Today and yesterday, I converted a huge pile of 8/4 stock into perfectly dimensioned and squared stock. I also cut all the top pieces to exact length, and I cut the leg top dovetails. All this took me 9 hours. I can't even begin to imagine how long it would take to do with hand tools. You must be an incredibly determined person and my hat's off to you.
Here are pictures of my progress to date:
Attachment 201308
Since all stock is dimensioned exactly the same, I will laminate the legs into the top with dovetails going in two directions. These pictures give an idea:
Attachment 201309Attachment 201310
Regards,
Hans

Oh boy! I think that you've really created a headache of a glue up with this design. I would hazard a guess that all of the theoretical benefits of your joinery choices will be severely compromised by the glue up process. I can see trouble getting glue and tight tolerances at the same time. I'll be interested in an update.

[David Wadstrup]

Hi,

I'm at a point, again, where I need some advice. I'm most of the way through cutting the 12 mortises that I'll need to join the rail's tenons to the legs. So far, I've chopped them both by hand and with the help of a drill press. It turns out that using a drill saves almost no time when the size of the mortise is as wide as the chisel. In fact, I prefer chopping it by hand, and I feel like I do a better job this way(although I do appreciate that the drill is considerably quieter). Anyways, these are the first mortises I've ever cut. They are all clean and relatively square. They are by no means perfectly square. Nor do they perfectly match one another. Here are my questions:

How square do they need to be? Do they need to perfectly match one another?

I understand that perfectly matching mortises would be ideal. It would allow me to cut all of my tenons to a standard size that could theoretically fit into any of the mortises I've chopped. My concern, though, is that I would not be able to tune them all square, and tune them to be of identical sizes, without significantly enlarging them. This would not be a good thing. Also, my thinking is that my time and effort would be better spent in cutting and fine tuning tenons to fit the specific mortises that they'll mate with. This wouldn't take any longer than it would for me to fine tune the mortises to a standard size and squareness, I'd bet. Does this sound like reasonable thinking?

And regarding squareness... Is perfectly square on all 5 interior sides necessary? I do understand that the joint will have to be perfectly square. But, I can have a slightly out of square tenon and a slightly out of square mortise and still end up with a square joint, right? If so, is having a perfectly square mortise and a perfectly square tenon necessary? What is your advice?

oh...

In case it makes a difference... The short rails will be permanently affixed to the legs with drawbore pins and glue. The long rails will attach with hardware that will allow me to dismantle the bench -- in other words, with no glue.

Thanks for your help. I really appreciate whatever advice you can offer that will help me move forward.

Thanks,

David

[george wilson]

I don't understand Hans's dovetail legs either. My workbenches at the 18th.C. shop had a straight up and down dovetail on the front edge of the legs,and a straight tenon like Hans's,so they could slide into the top from beneath. I can't see how the tapered dovetail can be assembled.

[Tony Shea]

It seems as though he plans on laminating the legs together while he is seating them in their given mortises/sockets. Maybe he will drive the straightish tenon part of the leg into the top, which is probably the inside part of the leg, then add glue to the face of that leg. Then pound the dovetail part of the leg into its' socket, which the dovetail socket would need to be on the show edge of the top, which would end of creating a lamination of the legs if all the joinery and dimensions are correct. This is the only way I see this method possible, and even then I think will turn into a nightmare. Too many slight variables that could go terribly wrong and end up with a disaster of a leg. The traditional roubo mortised leg would have made much more sense and be a better outcome even if the the original plan turned out well. We shall see if any of this is the case, hopefully. Sorry to hijack the bench build thread, can't wait to see the progress in pictures of the OP's build.

[Salem Ganzhorn]

David, I just finished assembling my bench (go to nc woodworker dot org and look for "I started my workbench").

I did the jointery with a combination of hand tools and power tools.

When I assembled my bench my mortises were not all perfectly the same size. This did not cause any real problem because I tuned all the tenon's with hand tools. The router plane got a great workout. At this point I was very happy that the side walls of the mortises were parallel with the sides of the legs. It is also critical that the opposite sides of the stretchers are parallel (the router plane references off of these surfaces to tune the tenons).
I also think the sides of the tenons must be very close to perfectly vertical. You don't want the joint to bind at assembly.
Good luck!
Salem

[Michael Peet]

Hi David,

I'm no expert but here are my thoughts -

How square do [the mortises] need to be?

As square as possible, particularly in the in-and-out direction; as Salem indicated you want to avoid binding.

Do they need to perfectly match one another?

Nope, just their respective tenons.

I understand that perfectly matching mortises would be ideal. It would allow me to cut all of my tenons to a standard size that could theoretically fit into any of the mortises I've chopped. My concern, though, is that I would not be able to tune them all square, and tune them to be of identical sizes, without significantly enlarging them. This would not be a good thing. Also, my thinking is that my time and effort would be better spent in cutting and fine tuning tenons to fit the specific mortises that they'll mate with. This wouldn't take any longer than it would for me to fine tune the mortises to a standard size and squareness, I'd bet. Does this sound like reasonable thinking?

I think it is easier to tune the tenons. When I built mine I cut the tenons first, marked each mortise from its tenon, cut the mortises, and then did any tuning on the tenon.

Is perfectly square on all 5 interior sides necessary? I do understand that the joint will have to be perfectly square. But, I can have a slightly out of square tenon and a slightly out of square mortise and still end up with a square joint, right? If so, is having a perfectly square mortise and a perfectly square tenon necessary? What is your advice?

The back of the mortise doesn't matter; in fact, the mortise should be slightly deeper than the length of the tenon. As for the other sides, I suppose I can imagine a case where the mortise and tenon are equally out of square so you end up with a square joint, but why make things hard on yourself?

One trick to getting square sides on your mortises is to use a guide block.

P1020324.20.jpg

Mike

[David Wadstrup]

Mike,

Thanks for the feedback and for the guide block recommendation. I'll definitely try it tomorrow.

I've been using chisels, too. I was wondering if you(or anyone) has any experience with Lie-Nielsen's joinery floats. Do you think they'd help a novice mortiser out? These are the ones I mean.

Thanks,

David

[Michael Peet]

Hi David,

Sorry, I've never used the floats. As for the guide block, two additional notes:

1. A piece of folded fine-grit sandpaper between the guide block and work piece will add a lot of friction, which is good because it will prevent the block from moving as you pound on the chisel.

2. Make sure the block itself is square! More importantly, make sure the guide face is perpendicular to the face of the workpiece after you clamp it in place.

Good luck!

Mike

[Steve Branam]

David - There is substantial evidence from remaining tool marks that wasting the majority of a large mortise with a drill bit and paring the walls square with a chisel was standard practice in the age before the advent of power tools. I've personally seen evidence of this in a circa 1780 timber-frame structure that was taken apart for moving. In many of the mortises, there are the tell-tale imprints of the center spur of a center bit on the bottoms of the mortises.

A fairly standard bit of equipment for timber-framing was a two-hand-cranked boring machine, I assume used for both mortises and treenails ("trunnels"). It had a base that rested on the timber, and uprights for the mechanism, including a rack-and-pinion to guide the bit straight down (I think it also included a drive-gear mechanism to advance the bit). They could take pretty hefty bits that would be a bear to drive with a brace. A fellow had a bunch of antique machines for sale in Nashua this spring, some wood and iron, some all metal.

[David Weaver]

A fairly standard bit of equipment for timber-framing was a two-hand-cranked boring machine, I assume used for both mortises and treenails ("trunnels"). It had a base that rested on the timber, and uprights for the mechanism, including a rack-and-pinion to guide the bit straight down (I think it also included a drive-gear mechanism to advance the bit). They could take pretty hefty bits that would be a bear to drive with a brace. A fellow had a bunch of antique machines for sale in Nashua this spring, some wood and iron, some all metal.

These are, or at least were, a popular staple at antique markets here (well, in central pa) prior to ebay. They weren't particularly expensive, either, but at the time I wasn't that interested in woodworking, so no clue if they worked or not.

another popular thing people have been hanging on their walls here long before ebay are the T-shaped auger bits (large ones) with fixed handles. My parents used to get a bunch of that old stuff from auctions, almost free. Anything that is pretty enough to hang on a wall now, though, is not quite as cheap. I wouldn't want to turn one of those all day, but it would beat swinging a hammer to cut those deep mortises.

No clue how the amish drilled the holes when I was a kid - might've been the reason there were so many still around. But as time goes on, it gets harder to tell where they still use hand tools.