Metal: It’s Like It Grows On Trees
Often, when talking about milling a log, I talk about the potential for it to have metal in it. I take for granted that everyone knows what I am talking about, but I was reminded recently that it is not always the case. I mentioned in an earlier post that a log had metal in it, and a friend of mine didn’t know what I was talking about. He asked, “How does metal get in trees?” Well, I am here to tell you how – any way imaginable. You name it, if it is made of metal, it is probably in a tree somewhere.
This horseshoe is on display at Mueller Brothers Timber.
You see, trees are magnets for pieces of metal. Young boys put them in trees for fun. They might be in the form of one small nail to hold a target or a series of large nails every 12″ to anchor tree house steps. Single trees in a fenced-in back yard are especially susceptible because they are sitting ducks and the focus of much attention. Even adults get in on the action with big hooks to hold hammocks, clothes lines, and bird feeders. Not to mention the trees close to the street that get nails from everyone’s signs.
The beauty of the nail is that there is usually more than one. I always say, “Why put in one nail, when you can put in twenty?” I have often thought that if I find one nail, I should just ditch the entire tree, but that is usually only on hot days, and when I am cutting low-grade logs. Otherwise, I suffer through it, dulling blades and cutting at a slower pace, while I check the log with a metal detector before each cut. On those same days, I often think about a new program that I will start for school-aged children called “Save The Lumber,” where I will teach the importance of hammer restraint.
Nails are removed by cutting around with a chainsaw and then popping out the chunk with a hammer.
The secret to the metal situation is that the trees grow over the metal. Nails that were driven 70 years ago are deep within a log, with no sign on the outside. Certain trees, like oaks especially, will show stains on the end of the logs from the metal reacting with the tannin in the wood, but that doesn’t tell you exactly where the metal is, just that there is metal close. So these things just sit in there, waiting to tear up the saw blade. They usually don’t ruin the blades we use on the portable mills, but they make them very dull and mess up the set (which is the amount the teeth are bent out to provide clearance for the blade). Larger pieces of metal can wreak havoc on bigger equipment though, and be very dangerous. In fact, putting large pieces of metal, like railroad spikes, in trees was a tactic used by activists to try to deter logs from being harvested. These days, all mills have metal detectors, so this is less of a problem at the mill.
A nice wide elm board ruined with nail holes.
I get most of my logs from an urban environment and know that the bottom log is prone to have metal in it (usually between 4′-5′ from the ground, where people can easily reach). For me, it is part of the deal and I work with it. There are, however, plenty of logs that are better not to cut, but I usually suffer through them anyway. I had one recently that prompted this post, and I have put up a photo of the carnage to drive home the point. It was a beautiful 14′ long super-straight elm log that would have produced wide and perfect boards, except for the nails, nails, and more nails. It also happened to be the one that bent up my mill, causing me to make a new part, which I decided to grind on, which created sparks, that, in turn, burned down my shop. That was a log that I should have never messed with!
Siberian Elm And American Elm: Leaders Of The Elm Revolution
I cut elm logs whenever I can – too much probably, because the market for elm isn’t that great. It isn’t because elm is terrible, it’s because most people have never used elm, and most people have never used elm because it isn’t readily available.
Well, I am here to change that with my not-so-new (drum roll please) Elm Revolution. This movement started after I used elm for the first time about 15 years ago and, to be frank, hasn’t quite taken over the world. Alright, alright, it hasn’t gotten much further than me and a few of my friends, and I don’t know why. I think elm deserves a place in the top ten of hardwoods for everyone, with Siberian Elm in the top five for me. My top ten goes something like this:
- Cherry
- Walnut
- Quartersawn white Oak
- Siberian Elm
- Soft Maple (with character)
- Eastern White Pine
- Flatsawn White Oak
- American Elm
- Quartersawn Sycamore (I rarely use flatsawn because it is too unstable)
- Red Oak
Note: My choices are limited to species available locally in St. Louis, MO. However, almost every domestic hardwood grows in this area.
The order of the species will fluctuate depending on the job, but both the elms are always in my top ten. If the job will be made completely from solid wood and I have elm available, I almost always present it to the customer as a choice.
Siberian Elm has a unique grain pattern.
Of the elms, the two that lead my revolution are Siberian Elm and American Elm. I like them both and choose between them and other species depending on a few variables. The first is the color of the wood, specifically the color of the final piece. Both elms take stain easily and consistently, very similar to oak, which makes medium to darker colors easily achievable. However, when I am looking for a white wood, the elms aren’t the ticket. Siberian Elm is mostly heartwood, which is a medium brown, and American Elm is usually stained in color (from standing dead after succumbing to Dutch Elm disease).
The second variable is the grain pattern and how pronounced it is. Siberian Elm has a strong grain pattern, especially when stained. It stands out a lot and is not the wood to use if subtlety is desired. However, if you are looking for a showy wood, the elm’s are for you. Siberian Elm is the standout of the two, and commonly has small knots that can range from just a couple per board, to a birds-eye look, and even heavily burled. It is not uncommon for only one in ten logs of Siberian Elm to have straight grain, with the rest having varying degrees of funkiness. American Elm is more consistently straight-grained, refined, and stains with less contrast. The beauty of American Elm comes from the grain itself and not from the growths within it. The interlocked grain of the elms causes a little zig-zaggy pattern between each growth ring that looks like a feather and is best seen in flatsawn boards. The figure has an iridescent quality about it and really pops with a dye stain.
Andy & Tyler (WunderWoods) show off the waviest Siberian Elm boards.
A big issue, and the third variable, is stability. Elms do not dry flat and are more unstable than other woods in service. When I pull boards from the kiln it is easy to tell when I have gotten to the elms. Siberian Elm will dry with cup, bow, twist, and crook, as well as a lot of waves, especially in lower-grade boards like those in the photo to the right. American Elm is just as cantankerous, but doesn’t usually have the waves. It goes strong towards cup and twist. The amazing thing is that after drying and straightening the boards on the jointer, they stay relatively flat. Notice, I say relatively, because they can still move a little if they are not quartersawn (everything is more stable if it is quartersawn). Because of this potential for movement, I don’t use elm where movement may cause something to get out of alignment and stand out. For example, I would use elm on cabinets with larger gaps between the doors, but not on large cabinet doors where I was trying to maintain perfect reveals – it is just asking for trouble.
This American Elm is straight-grained, but stood dead for awhile.
Elm ranks low on the durability scale, which is the fourth variable to consider. Because of this, I only use elms indoors. In the log form it rots pretty quickly and starts to have issues after only one season outside. Both elms can be used for anything inside, including flooring. American Elm is harder than Siberian Elm, which I compare to walnut, but I have done floors with both, and they seem to stand up fine.
Siberian Elm table by Martin Goebel of Goebel & Co. furniture.
Availability may be the biggest hurdle to overcome after you decide to give elm a try. Elm is not readily available in either American or Siberian. American Elm is scarce because it is attacked and killed by Dutch Elm Disease, which has wiped most of them out. They are still out there and get to good size, but are usually only available after they are dead. If they are alive, most people prefer to leave them standing because they have a nice shape. Siberian Elm was brought in as a Dutch Elm Disease-resistant tree and only grows in areas where it was planted (though it does reproduce prolificly and spread from where it was planted). Because of this Siberian Elm mostly grows where sawmills aren’t, which means it doesn’t get cut very often.
The main difference when working with elm compared to other woods, is the interlocking grain mentioned earlier, which kicks hand planes and several other hand tools out of the equation. Other than that, they work like most any other hardwoods.
Jeff Herman (WunderWoods) installs a Siberian Elm front door.
If you get a chance to use an elm, especially Siberian Elm, give it a shot and help move this revolution thing forward. I know a lot of people who have tried them and liked them. As a matter of fact, two of my friends have just introduced furniture lines with Siberian Elm as a choice. Long Live Elm!
Why Quartersawn Lumber Is So Stable: The 0-1-2 Rule In Action
So, now because of my earlier post, “Have You Heard About Shrinkage,” you’ve been thinking 0-1-2, 0-1-2, slow, slow, quick, quick (if you’ve ever taken a dance class with your wife you’ll get that one), and you are still a little confused. Most likely you got bored reading about the 0-1-2 rule I wrote about earlier and drifted off, but this is where it all comes together.
Lumber basically comes in three categories of cuts, which refer to the angle of the growth rings in relation to the surface of the lumber; flatsawn, quartersawn, and riftsawn. A board can be any of these three or anywhere between these three, and since the growth rings form a circle, the category can even change within a board. That’s right, wider boards can have centers that are flatsawn while the outer edges are riftsawn and possibly quartersawn. That is why I push for an understanding of the cut of lumber and worry less about the name.
Lumber cuts are determined from the end grain, not necessarily from the process that produced them.
To the right are the three cuts in their most pure form (the three in the top right of the log diagram) and others that are thrown in for fun. The “fun” ones are to show that it doesn’t matter what process was used to get the lumber from the log (flatsawing, quartersawing, etc.) or its orientation in the log, it is the growth ring direction that counts. The growth rings of flatsawn lumber are parallel to the widest surface, while the growth rings of quartersawn lumber are perpendicular to the widest surface. The rings of riftsawn lumber are at a 45 degree angle. Remember, these refer to their purest forms and there are many cuts in between (as demonstrated by the “fun” names like Nifty Rifty Flatsawn).
This illustration shows how little quartersawn lumber shrinks compared to other cuts.
The next illustration shows the 0-1-2 rule in action. The three illustrations are table tops glued up from several pieces of wood. The first one is flatsawn lumber, the second is riftsawn, and the third is quartersawn. The numbers represent proportionally how much each piece will move in a given direction (remember that the length moves 0). In this case it is shown as shrinkage from a low-humidity environment, but it could also be expansion if the piece was stored in a high-humidity environment. Either way, the proportion of movement is the same. To make the proportions mean something, make them into fractions. Across the width, flatsawn lumber moves 2 over 1 when expressed as a fraction or 2/1, which simplifies to 2. Quartersawn moves 1 over 2 or 1/2. If you compare those two numbers (2 to 1/2), flatsawn moves four times as much as quartersawn across the width.
If I didn’t just lose you, then you can see by looking at the numbers and the second illustration that quartersawn lumber has the least amount of movement across the width, while flatsawn has the most. This makes the quartersawn the more stable of the two as far as expansion and contraction goes.
The other advantage to quartersawn lumber is its ability to stay flat. While flatsawn lumber has a propensity to cup, quartersawn lumber does not cup, and the 0-1-2 rule is the reason why. All of the heavy internal forces exerted on quartersawn lumber are in the thickness of the wood and going in only one direction, and they have little effect on the shape of the lumber. Those same forces on a flatsawn board are going across the entire face and in an arched trajectory. When these forces pull hard during shrinkage or push hard during expansion, they cause the lumber to take an arched shape that we call cup.
Quartersawn lumber will stay flat and move the least amount when in service. However, it is not so stable that the wood movement can be ignored in construction. When joining two boards, any movement between them that is not proportionally the same and in the same direction must be addressed by allowing the wood to move. Remember the 0-1-2 rule, and look at the boards you are joining to see if the numbers match. It is as easy as 0-1-2.
What’s Going on at WunderWoods
Everyone always asks what I do. Here's the answer. Click on the photo above for a short video tour and see all of the steps it takes to go from a tree to finished furniture.