green woodworking

I have only done some minor tinkering in this space.  And I would like to do lots, lots more. 

One thing I keep thinking of trying is to merge dry wood with green wood.  If the dry wood were the dowel piece and the green wood had the hole, then wouldn't the green wood shrink around the non-shrinking dowel?  Would it then become a tight enough bond that glue or any additional bonder would be unnecessary?

Probably shrinkage will be somewhat unpredictable and will tend to split around the weak spots (ie dowel holes). It's worth trying I guess. Nothing to lose except time. I'm certain there are ways that this will work.

An architect friend of mine told me about entire houses built this way some time ago.

I got the impression the dowels were large, perhaps half an inch?  Cracking gets much worse as hole diameter decreases, all else being equal.  You definitely do not want inside corners!

I seem to recall shrinkage is fairly predictable, based on species, ring spacing and moisture level.

Similarly, quenched steel shrinks as it is tempered, so interesting things can be done with piano wire.

Cracking gets much worse as hole diameter decreases, all else being equal.

I would think the opposite would be true.  Typo?

Similarly, quenched steel shrinks as it is tempered, so interesting things can be done with piano wire.

And now I'm blown out of the water.  Somehow I imagine the steel shrinking as it goes from being too hot to touch to room temp.  But I figure piano wire is always room temp.  Are you suggesting that you heat piano wire and then do something with it?

If you wound something in piano wire, fixed that wire in place, and then baked it in an oven, a chemical change would take place in the steel, causing it to lose some strength but form a denser crystal structure.  The structural change would be permanent, and probably larger than the thermal expansion.  This constriction would add up to huge amounts of force over many turns of wire.

A traditionally-made katana is actually straight-edged before heat treatment; quenching the edge causes it to expand, introducing the curve and building in compressive stress that tends to close any nicks in the edge (same idea as tempered glass).  The back of the blade goes through some quenching, but not nearly as much.  The curve is adjusted by hand, by placing the back of too-straight sections against a hot cylinder of copper and annealing/shrinking them little by little.  It is no coincidence that Yamaha makes good piano wire etc.

>I would think the opposite would be true.  Typo?

I should maybe re-phrase more precisely:

A sharper inside corner will give first, under a given level of stress. 

There is no "all else being equal"...other things have to change, and I have some training as to what changes my profession thinks are important.

So: taking a green beam/dry dowel house and scaling it down to a dollhouse, dowels and all, may introduce splitting around the dowels, because stress concentrates more sharply in those small dowel holes than in the full-scale ones.

(Incidentally, scaling will also cause the structure of the dollhouse to be crazy over-built, able to withstand being inverted and even tossed around Wizard of Oz-style...but I guess we all know that.)

But drilling a larger hole in the same size of board would, as you expect, probably make splitting more likely.

Paul, Caleb, and Krista review Ben Law's "Roundwood Timber Framing" DVD in this podcast: http://www.richsoil.com/permaculture/381-podcast-058-ben-law-roundwood-timber-framing/

One thing I keep thinking of trying is to merge dry wood with green wood. 

    It should also be possible to work with all green woods by choosing woods of different shrinkage rate. If wood with a low shrinkage rate is used for dowels then everything should lock together nicely when the outer wood shrinks more. This would allow for easier shaping of dowels and tennons since they can be worked with a drawn knife while they are green.

We build all of our structures with “green wood” right off the saw mill.  That way the timbers are straight & true and notching is much simpler.  Shrinkage isn’t a big issue, but warpage can be.  With these structures using mortise & tenon and pegs warpage isn’t an issue.  The more the member tries to warp the tighter the joints get.  Cladding should be dry.

You might help prevent cracking/checking/splitting by painting linseed oil, beeswax or liquid wax on the green wood, and repeating it over time (how much depends on the wood's oil content) as it dries - this way it dries slower.

Also oil the peg and leave it for a while so it doesn't expand when it sucks in some of the oil from the green wood.

Other tricks that might make a small difference:
- apply linseed oil inseed the hole
- spin/ream a twist drill bit in a reverse direction in the hole to heat-harden the hole a little (or use something else if the hole's too big for a twist drill bit)
- apply sealer and/or varnish
- cover with a plastic bag or similar for the first few years, especially if it's in a place that'd make it dry quickly or that's prone to large temp variations, just

From http://lumberjocks.com/projects/34463
"Checking is a problem due to too quickly drying the wood whether it be in log form or in the green stickered lumber.

Too much air flow or heat will accelerate the drying process which can vary greatly between species.

Air drying can cause cause excessive loss in lumber IF not properly handled, but so can improper kiln drying.

white oak/ red oak are some of the worst to dry in terms of difficulty and poplar and pine the easiest."

Sycamore and birch are two other species prone to cracking. Generally, hard woods crack less.

I had the privilege of listening to Brian Boggs who has been making greenwood chairs for over 20 years. He has made many chairs using greenwood technology. There is no glue involved. The legs are green and the cross members are dry. The moisture of the greenwood moves into the dry wood which swells and creates a "near permanent" joint. There are many chairs made this way that last over 100 years.

as a spinning wheel builder I'm very interested in this space. I use a lot of glue right now, and I'd really rather not.

When dealing with wood, you want to make sure to seal the ends. Of course, if the ends are buried inside another piece, life is good. Wood splits often because the ends dry (more surface area) much quicker than the middle.

Also, when drying, the idea is slow and steady, and give it time to rest. Solar kilns often provide some of the best results because things cool down overnight. This allows the wood to equalize (the middle often is wetter than the surface during drying), reducing stress, and checking.

Dry to fast, you get what is called "case hardening" where the outside is dry, and sealed, but the inside is still wet.

Remember as well, when something is drying, it really doesn't shrink much on the length, but on the width. A given type of wood should dry pretty much the same, as long as you are using heart wood, or sapwood, i.e. similar densities.

Green woodworking is cool stuff, we have furniture from when my wife was a child in school made that way, and it is still sold. We have woods down here so hard that you almost can't work with them, except green.

hello, this is my first post here. ive done a bit of green wood working (rustic chairs, carved spoons, and lathe turned bowls). mostly spoon carving. green wood can be a real joy to work. i made a spoon carving video not too long ago, ill see if i can embed the first one here. cheers. Jaime.
hmm, couldnt figure it out. here's a link instead.

Here is an interesting series of videos on green woodworking. Not much details, but ideas of what is possible.

The fourth one shows them making a really strong joint without glue or dowels.

He also has a book:

In some timber frame construction I've done, I used dry, square, oak pegs in green wood holes. Pegs remained tight after green wood seasoned.

John Merrifield wrote:In some timber frame construction I've done, I used dry, square, oak pegs in green wood holes. Pegs remained tight after green wood seasoned.

Ditto, but with roundish pegs and big spikes. The greenwood I've used has been tamarack, spruce, cedar, pine, and poplar(black aspen) with the majority being spruce and tamarack. The pegs have been oak and mountain ash, but I hear black locust is good too. I've had a few major cracks where I put the peg too close to end of the board and it compromised the joint, but they have been few and with cedar and spruce.

One example of the strength is my buddy and I built his small barn with timbers mainly joined with oak pegs and tamarack boards. It would take a few pounds of dynamite and an act of God to knock that building over. It is SOLID. That tamarack was fine to work with green but needs a hole drilled to drive a nail dry.

I just found out I was not getting notificaiton from this section of the forum. I will try writting some articels soon on this subject...in the interim I can answer any question folks may have.

Regards,

j

I have used black locust and had good results. Also, the square pegs I referred to aren't exactly square. They start round and are then flattened on opposite sides. The peg is inserted in the hole with the still round parts running with the grain of the timber and the flat parts opposite the grain. As the green timber shrinks the pressure to split the timber is alleviated.
Maybe. using a recessed joint with a shoulder when worried about split-out would solve the situation near the end of a board.
John

jaime merritt wrote:hello, this is my first post here. ive done a bit of green wood working (rustic chairs, carved spoons, and lathe turned bowls). mostly spoon carving. green wood can be a real joy to work. i made a spoon carving video not too long ago, ill see if i can embed the first one here. cheers. Jaime.
hmm, couldnt figure it out. here's a link instead.
http://www.youtube.com/watch?v=-GmAHftCgDo&feature=player_detailpage

Nice work Jaime. Enjoyed your spoon carving videos.

When you drill the peg holes,be sure to elongate them vertically[in the tenon].This will prevent the shrunken beams frombeing hung on the pegs only and allow the sole of the beam to settle and be supported by the tenon or should[if used]the pegs are meant to hold the joint in place .The jont itself supports the weight.
*Also,Windsor Chairs have been made for centuries using the shrinkage of different woods to form permenant joints.Higher moisture in the legs ,less in the runners.

Hi Paul,

From your experience with what you just posted above, could you provide any pictures and a better breakdown of the description and why you do these different alteration in the joint to make them function. Even I got a little confused by your descriptions when and wheres.

Thanks,

j

I'll try though I don't have a picture of the open joint.I am a novice at timberframe compared tothose that do it for a living.In this picture you can see that I cut out the post ,where the cross timber seats to for a shelf of sorts.As a green timber dries it will shrink so if the peg hole in the tewnon is a tight round fit ,the peg will end up bearing all the load .The shrinkage will lift the cross timber off the shelf.By elongating the tenon hole vertically the cross beam can settle back down on the shelf as it dries. there.clear as mud now ,right?

O.K. Paul, if you don't mind, I am going to "dissect" your post and see if I can break some of it down and perhaps alter a few points for clarity and correction.

In this picture you can see that I cut out the post

I will take that you mean "jointed" the post when you write "cut."

where the cross timber seats to for a shelf of sorts.

Well the "cross timber" is the "bent girt" or "bent beam" those between the different bents (primarily European modalities but also in Middle Eastern and Asian as well as in other timber framing cultures) are called "connecting girts" or "or connecting beams."

The "seat" that forms a "shelf" is the joints "bearing point" and is generally, in its entirety, called a "housing."

As a green timber dries it will shrink so if the peg hole in the tenon is a tight round fit ,the peg will end up bearing all the load . The shrinkage will lift the cross timber off the shelf.By elongating the tenon hole vertically the cross beam can settle back down on the shelf as it dries.

That is neither traditional, nor good practice. The "bearing point" of the "housing" should take all the primary load that is subjected to the joint from gravity and all tectonic loads. That part you have correct. In in many designs, the peg is only there for getting the frame together, and could be remove latter, as it is not really needed at all. Better yet, do not design joints that need pegs, but instead relies on a "draw or compression" wedge, or gravity to make the joint work over time. "Draw pinning" is the method of keeping joints tight both in general format and to the beary surface and this is done by "offsetting" the "trunnel" or "peg" hole in the receiving (mortised) member, not by elongating the hole in the tenon which is not traditional or necessary. I would also not that oblique braces are often not peg at all (nor should they be as they work in compression load only,) nor is there enough "relish" in the long grain of the brace tenon to make the pegs functional, often making the joint weaker and failing as oblique braces do in general the smaller they get in length, as they react to tectonics within the frame making them a fulcrum on the nearest joint. Most (almost the majority) of timber frames built through history (other than in Europe and the last 400 years by Europeans in North America) do not use oblique bracing, but instead use "horizontal" bracing modalities. The Middle East through to Japan, has relied on "horizontal" bracing and tying systems more successful against tectonic load than anywhere else in the world, and still do. This is why they have the oldest frames and the oldest sustained timber framing cultures (other than some small pockets in the Swiss Alps and Carpathian mountains.)

Sorry that got long winded, but it was warranted. Thanks for making it possible and good luck with your timber faming. Let me know if I can help (or confuse ) you more than I have thus far.

Regards,

j

Jay C., I am curious regarding the horizontal bracing versus oblique bracing. Triangles are rigid forms, while rectangles are not. At first glance this would make it seem like oblique bracing would be a good idea.

Am I correct that in actual practice, the horizontal bracing having a little more play becomes a benefit during seismic activity? The rigid frame resists movement - and fails, while the less rigid frame moves a bit and so does not fail?

Some explanation as to why the one works better would be appreciated.

Hi Peter E. et. al.,

You have the general idea, and in do course I will be writing a rather lengthy article here at Permies on this and related topics to timber framing. In the interim:

Oblique bracing hold till they fail, and when they fail the frame fails catastrophically. Horizontal framing allows for appropriate movement, fails slowly, and often is "sacrificial" to the rest of the frame so after a major tectonic event (seismic or wind) the frame can be rebuilt by the occupants because both they and the home survived.

Another way to think of it is along the mind set of the Martial Arts. As a practitioner, I teach students to bend to the wills of the aggressor, and allow their attack to move past you. While in many of the "European" pugilistic arts, the body is held rigid (as often is the mind) and you either resist, or fall to your own weakness and overpowering attack of the opponent. The architecture is the same...

Regards,

j

Jay C. White Cloud wrote:O.K. Paul, if you don't mind, I am going to "dissect" your post and see if I can break some of it down and perhaps alter a few points for clarity and correction.

In this picture you can see that I cut out the post

I will take that you mean "jointed" the post when you write "cut."

where the cross timber seats to for a shelf of sorts.

Well the "cross timber" is the "bent girt" or "bent beam" those between the different bents (primarily European modalities but also in Middle Eastern and Asian as well as in other timber framing cultures) are called "connecting girts" or "or connecting beams."

The "seat" that forms a "shelf" is the joints "bearing point" and is generally, in its entirety, called a "housing."

As a green timber dries it will shrink so if the peg hole in the tenon is a tight round fit ,the peg will end up bearing all the load . The shrinkage will lift the cross timber off the shelf.By elongating the tenon hole vertically the cross beam can settle back down on the shelf as it dries.

That is neither traditional, nor good practice. The "bearing point" of the "housing" should take all the primary load that is subjected to the joint from gravity and all tectonic loads. That part you have correct. In in many designs, the peg is only there for getting the frame together, and could be remove latter, as it is not really needed at all. Better yet, do not design joints that need pegs, but instead relies on a "draw or compression" wedge, or gravity to make the joint work over time. "Draw pinning" is the method of keeping joints tight both in general format and to the beary surface and this is done by "offsetting" the "trunnel" or "peg" hole in the receiving (mortised) member, not by elongating the hole in the tenon which is not traditional or necessary. I would also not that oblique braces are often not peg at all (nor should they be as they work in compression load only,) nor is there enough "relish" in the long grain of the brace tenon to make the pegs functional, often making the joint weaker and failing as oblique braces do in general the smaller they get in length, as they react to tectonics within the frame making them a fulcrum on the nearest joint. Most (almost the majority) of timber frames built through history (other than in Europe and the last 400 years by Europeans in North America) do not use oblique bracing, but instead use "horizontal" bracing modalities. The Middle East through to Japan, has relied on "horizontal" bracing and tying systems more successful against tectonic load than anywhere else in the world, and still do. This is why they have the oldest frames and the oldest sustained timber framing cultures (other than some small pockets in the Swiss Alps and Carpathian mountains.)

Sorry that got long winded, but it was warranted. Thanks for making it possible and good luck with your timber faming. Let me know if I can help (or confuse ) you more than I have thus far.

Regards,

j

ok Jay,that's why I prefaced thew post with "I'
m a Novice" I can only teach what I found.I did draw pin them when I did them to bring them tight.I went with what I read when researching.I'm not a big termanology guy so keep it in simple terms to avoid using the wrong term.Thanks for the clarification.i'm sure the others can learn more from your experience.

Hey Paul,

Your doing great, and keep up the good work. Glad you are draw pinning, that is a lost art all its own. You should be fine as you perfect your "pinning" technique in keeping the joint tight and down onto its bearing surface of the housing.

Keep it up and posting more photos as you get them...it will inspire others that think they can't...terms are only for us "timber geeks," and "academics" what is important for your is satisfaction and building a beautiful frame.

Regards,

j

thanks jay,The shop is being made from Green Hemlock timbers so movement is likely in one way or another.That's the biggest reason I did what i did.i figured the housed joints would add to the integerity of the joints over the long haul as the timbers dry out.

Fred Morgan wrote:When dealing with wood, you want to make sure to seal the ends. Of course, if the ends are buried inside another piece, life is good. Wood splits often because the ends dry (more surface area) much quicker than the middle.

Also, when drying, the idea is slow and steady, and give it time to rest. Solar kilns often provide some of the best results because things cool down overnight. This allows the wood to equalize (the middle often is wetter than the surface during drying), reducing stress, and checking.

Dry to fast, you get what is called "case hardening" where the outside is dry, and sealed, but the inside is still wet.

Remember as well, when something is drying, it really doesn't shrink much on the length, but on the width. A given type of wood should dry pretty much the same, as long as you are using heart wood, or sapwood, i.e. similar densities.

Green woodworking is cool stuff, we have furniture from when my wife was a child in school made that way, and it is still sold. We have woods down here so hard that you almost can't work with them, except green.

What do you use to seal the ends?

I am not sure if the movie ever came out, but the preview in itself is cool.



The same people also made this movie of someone turning a bowl with a pole lathe

Here in Maine they practically want you to give astern Hemlock away, but pay well for Spruce and Pine. To that end I sell the latter two and use my almost worthless hemlock into lumber. Almost everything I build is out of hemlock.

It is an interesting wood. Green it is super heavy, but you can drive a nail in it. Often times the water sprays back at you. But once the wood is dry, the wood will break before the nail can be withdrawn. In fact after a year of being built, it is easier to just cut the nails with a sawzall.

The only issue I noticed regarding building with green wood is in using Popular (or what we call Popil here). It has severe shrinkage issues. When I built my house many years ago I did have another slight issue, during the winter as my studs and rafters dried out, they would often pop. This sounded like a rifle shot which was not so pleasant at 2 AM!

here's a link to a new short spiffy video that is all about one of the bootcamp boots fixing up some chairs that were originally made with green wood.  In it, Stephen discusses some of the ins and outs of building with this method.