Roubo from Logs

I am interested in making a Roubo bench. It is something that I have wanted to do for a while, and I was recently offered some white oak logs. I am considering hewing them and this might be a total hand tool build.

I need some help with a hewing axe. What can I get by with? Can I rough it out with a regular axe and then go at it with my planes? Or do I really need a broad axe or adze? I just need to get it in a form that my planes can handle.

The second concern is drying. When I used to reclaim old lumber it seemed like oak really likes to check. I’m going to build it wet like any other timber frame, but then I wonder if I should keep it outside for a while or something?

I made my Roubo legs and stretchers from 150-ish yo oak logs. It was a wicked PIA and I would never do it again. I hit metal and ruined my planer, then jointer, blades. The money I saved was instead spent on aggravation. If I were you, id find a local sawyer and see what 12/4 stock he has at a decent price and go with that. I milled my logs square btw. I think that using hewn logs would present some real challenges when it comes to joinery.

Howdy Doug, and Welcome to stepping out of the lurking shadows after all these years. :cool:

A hewing hatchet/axe isn't too difficult to find. Mine was bought at an estate sale. It is a True Temper. It has a slight curve and is only beveled on one side.

As Peter mentioned, it is a lot of work to hew a log to a bench top. It might be easier to use a chain saw to start out.

Oak is also a bit difficult to work. The beautiful part is if you cut it yourself you can end up with the top being quarter sawn which would be quite nice looking.

Keep us posted as bench builds are always of interest.

jtk

Thanks for the replies. Years ago I worked for the lumber mill side of a company that reclaimed old wood. The other side was a timber frame operation, and I watched a lot of hewing. I wished that I had gotten more involved though.

Since then I went to work for a fire department, and live in a typical one story suburban home. So I haven’t done much woodworking in years. Now after a decade they are about to start clearing for another phase and after talking to them today it looks like I’m going to have access to some nice trees practically in my backyard. I could use an Woodmizer LT15, but I think that I’d rather take a shot at chopping them myself. The longest timber would only be 8 or so feet.

I’m going to try to document it pretty well, and maybe even have some videos.

Go for it Doug. We like bench builds and your plan may the most ambitious of all. Fortune favors the bold - no pain, no gain - go big or go home. You could end up with the Big Dog Trophy.

How much time do you have? White oak is the worst place to start. And planks for benches would have been sawn, not hewn. And lacking a saw, the log would have been split and the top surfaced with an adz. The bottom would have been unfinished. Hewing axes were use for "fine" work as walls were raised on logs that were near shape.

I believe I posted pictures on Stan’s post about Schwarz’s Roman Workbenches. The pictures show a red oak bench I have been working on. I was able to hew a rough shape out of half a red oak log, mostly using my larger chair seat adze. I split the original log in half. The wood was from a tree at our new home. It was not that hard to do. I do not own an actual hewing axe, yet. I have been searching auction sites looking for a good design. I may have to just buy one.

Schwarz and Will Myers, the Moravian bench guy, just did a joint video on making a roubo bench. They used relatively green lumber to make the top with and claim that it is ok to let the thick pieces dry on the bench. Not too long ago I suspect most workbenches were made with greener wood, as that was what people had.

Doug, you sure are talking about a phenomenal amount of hard work!

If you are heart set on doing this, rather than using an adze and ax combination to hew the bench, I would suggest that you use a handsaw or pit saw, as it will be much faster, accurate, and easier overall. This will enable you to start with a larger log and saw a single plank top that does not contain any pith wood. You can take your leg and stretcher lumber from the bottom side of the log (although you will probably need multiple logs). For a tradition 20" wide Roubo, you will need to mill a slab at least 24" wide (and wider is better). It will shrink around 2.5" in width and then you will have around 1.5" for straight line ripping the front and back edges.

Start with a log that is clear - no visible defects on the bark indicating former limbs below. Otherwise the varying grain pattern between the limb pith and the trunk pith will cause a lot of untoward wood movement, which will increase the amount of hand planing that you will have to do in the future.

To minimize sap wood, for a green 24" slab taken about 1/3 of the way from the outside of the log to the pith, you will need a log in the 30" plus range.

With oak, if you take your slab through the center of the log you will get significant checking running down the middle where the pith wood resides. That's why I recommend milling your slab further away from the pith.

Traditional Roubo bench tops are around 5" thick. With oak, depending upon where you cut the slab from the log you can expect shrinkage of up to 12% - either in width or thickness. If I was making a benchtop with a goal of having a 5" thick finished top, if I were only planning to S1S it I would mill around 6" thick. This will shrink to 5-1/2", give or take, and allow you 1/2" for flattening one side.

If you want to S2S it, better shoot for 6-3/4" green. A green bench top slab measuring 6.5" thick, 24" wide, and 96" long will weigh in the vicinity of 750lbs, give or take.

The quickest drying method that I can think of (without seriously degrading the wood), would be approximately 1 year air drying out of doors under a shelter, and then around 1.5 - 2 years drying in a solar kiln (with the goal of removing it from the solar kiln at the end of it's second summer). That should get you down to the 10% or lower range, give or take. Design your solar kiln so that the chamber is relatively small. A large chamber solar kiln may dry the wood too quickly and result in extensive surface checking. Keep the vents pretty much closed.

You will not see much shrinkage until the lumber dries below 30%, so for the first few years the slabs will remain relatively flat.

This page on my website shows a method I came up with one afternoon to "hew" a couple of beams. A broadaxe is a "finishing" tool only. The pictures should be self-explanatory. Please excuse grammatical errors that have showed up over the years from missing words, and whole lines of text. I've been too busy to work on it.
http://historic-house-restoration.com/structural.html

If this guy can do it, it can be done. Nice info. Tom, I may try a few of those techniques. There are tons of other videos on YouTube. I found one of a Japanese dude hewing barefoot, which is where I might draw a line in the sand.

There are lots of hewing axes, ome double bevel some single, right & left.....vast differences in size.

https://www.youtube.com/watch?v=O2R_ZyPqwfo

Remember, if you tackle this, that you want to remove the pith from any logs used on the benchtop, to avoid cracks.