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!
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.
Log Wins, Welding Begins
I own and run a TimberKing 1220 manual sawmill. The manual part means that it is not automated and less expensive than other bigger models. I have had several other sawmills, and overall I am happy with this one, though I would always like a bigger and better one. It is a small entry-level mill, but can still cut a log up to 30″, which is big.
In most ways my TimberKing mill is strong enough to handle the bigger logs, even though it is not really made for them. However, there is one area that I have found severely lacking, and that is the log supports. You see, when you put a log on the mill it may roll off, so the mill has two or three posts that can be raised into a vertical position to catch and hold the log during milling. They also can be lowered out of the path of the bandsaw blade when needed. The posts need to be strong enough to support the log in a resting position, and be able to handle the pressure placed on them when turning a log. They also need to be square to the bed to help make a round log into square lumber.
The log supports on my mill don’t do any of these things well. They are made from dainty little pieces of steel that can bend quite easily and are never square to the bed. Through the years I have bent them back – never to square, but back enough to support the logs. When I want a square cant (squared up log), I take the time to shim the log and use a carpenter’s square to make sure that everything is copacetic.
Both uprights (red) bent like wet noodles
Close-up of the upright, which used to be close to vertical and somewhat straight
Well, this week I finally did it. I put a large elm log on the mill, and I was adjusting it with a big loader when the log just rolled over the supports and off of the mill. It didn’t even notice they were there. The uprights looked like limp noodles, and it is obvious they aren’t going back to any acceptable shape. I bent them more than enough to finally provoke myself into making new ones.
The good news is that I bought the steel to do it a while ago, but have just never taken the time to do it. Looks, like now is the time.
Have You Heard About Shrinkage?
As woodworkers we have developed our skills worrying about shrinkage, many knowing that quartersawn lumber is more stable, but not really understanding why. We know a piece of wood is going to get fatter in high-humidity and skinnier in lower humidity, but to what extent, and how is that going to effect the shape of the lumber. If the lumber that is being used isn’t obviously quartersawn then what will happen? Is it flatsawn? Or, is it riftsawn? Or, maybe, kinda riftsawn?
I say stop worrying about, and trying to name, the condition of each piece of wood when trying to understand how it will move. A simple rule can be applied to the log to understand wood movement, which can then be easily translated to the lumber. Following this rule will tell you how the lumber is going to shrink, no matter which part of the log it came from or the direction it was cut. Just looking at the endgrain will tell you everything you need to now about the lumber you are using.
This illustration shows how the 0-1-2 rule is applied to lumber in the log form.
The end view of this white oak shows how logs crack or check on the ends as they dry out. The cracks open up because of twice the amount of shrinkage in a circular direction.
I call the rule the 0-1-2 rule, which is a simple ratio of wood movement in three directions in a log. The first direction is along the length of the log. Since the movement along the length is negligible the number is 0. Basically, lumber does not shrink in length. The next number, 1, is applied across the end of the log. In this direction the lumber does shrink, and in a ratio of 1 to the 2 in a circular direction, or half as much. The third number is the 2. In this circular direction, the log shrinks twice as much as it does across the log.
This 1-2 ratio is what causes all the kerfuffle in wood movement. Since the two directions aren’t shrinking and/or expanding at the same rate, wood can’t just be thrown together any direction and expected to stay together. These movement forces are great and will blow things apart or break lumber if not allowed to move.
There is a lot more to be said in a complete discussion of wood movement, but this rule lays the groundwork for all further discussions. Study this one and get to know it like the back of your hand. After you do, it won’t matter what the cut of wood is called, you can just look at the end of the board, envision where it came from in the log, and know how it wants to move.
“The” White Oak
This photo shows the color of fresh cut white oak on the left and white oak that was out for hours after cutting on the right.
Today, I was working on the large white oaks from the previous blog post, and I had a chance to snap a quick photo of an interesting phenomenon. On the stack of white oak lumber that I cut yesterday, I added some fresh lumber from this morning. It just worked out that I had two boards next to each other that clearly demonstrated a color change in white oak. This doesn’t happen in just any white oak, it happens only in “The” white oak, the one that is commercially sold as white oak.
You see, there are many different species of white oak in the white oak family of trees, like burr oak, swamp white oak, post oak and others, but none change color like “The” white oak. The change starts quickly after the lumber is cut. The wood goes from a tan color to a tan-pink or even just pink within an hour. However, don’t get too attached to the color because after the lumber dries for a day or two the color migrates back to the original tan color.
“The” white oak is not the only one to change colors after being freshly cut, but it is the only one where the color change is a key identifier. Others that change color include walnut, which goes from a green-brown color to a medium-dark brown color with no hint of green. Another one is cedar, which goes from a vibrant pink/purple to a medium-dark brown. The only other one that changes color like the white oak is ash, which develops a pink cast to it that then fades away in a day.
“The” white oak is in the white oak family and called white oak. This is tricky because it doesn’t have another name that clearly identifies it. For example, in the red oak family, the most desired species is called Northern Red Oak. But in the white oak family, the most desired species is also called white oak. I know that many people, including myself in the past, may be cutting a tree and wonder if it is “The” white oak. If it turns pink shortly after you cut it, it is.
Doyle Log Scale: How To Determine Board Feet In A Log
(Click this image for a larger view. Click the pdf link below for a printable Doyle log scale or Doyle log rule.)
Doyle Log Scale WunderWoods pdf
Many times customers will call to discuss having a log milled and how much it will cost. The answer is often based on how many board feet (12″ x 12″ x1″) will be produced. So, the first thing I ask is, “How big is the log?” Usually the answer is, “Well, I can’t get my arms around it.” And, while this may be helpful, there is a more accurate way to determine the size of a log and how many board feet will be produced.
There are three common scales or rules used in the industry (Doyle, Scribner, and International), but the Doyle scale is the most commonly used around the St. Louis area. All three of the scales estimate logs closely in the medium to larger size range, but the Doyle underestimates footage on the smaller logs. Because of this, it is advantageous for buyers of logs to use the Doyle scale to make up for extra log handling on small logs. Since the buyers like this scale, it is what they use and therefore, what the sellers use.
Doyle folding log rule used by most log buyers in Midwest
All buyers have a Doyle scale on them at all times, usually in the form of a folding rule with the footage marked at each inch. The printable version above has more increments on it, but it is basically the same and is used in conjunction with a tape measure. I always have a tape measure on me, so I usually use the printed version (they are also cheaper).
The formula for the scale is based on a tapered cylinder, milled with a 1/4″ kerf. Straight logs, with little taper and cut on a thin-kerf bandsaw will yield more lumber than the scale predicts. It usually averages out, because logs are usually not so perfect, and often have boards that are below-grade and end up in the firewood pile.
To use the scale, first measure the average diameter of the small end of the log inside the bark (in inches). Locate that row on the scale. Next, measure the length of the log (in feet). Move over on the scale to that length column. Where those two measurements intersect, you will find the board footage for that log. The process must be repeated for each log. Deductions are made for defects, like rot and curved logs.
Since sawmills usually charge by the board foot, this scale will help you determine the amount of lumber you will have and what you can expect your bill to be. Make sure to accurately measure your log and not just guess the diameter. The logs seem bigger than the actual measurement. My customers are usually off by about a foot in diameter on good-sized logs when they guess.
A little perspective on log sizes:
• A respectable diameter on a hardwood tree is 20″.
• A large diameter on a hardwood tree is 30+”.
• The smallest diameter most hardwood mills buy is 13″.
• The largest logs I get on a once-a-year basis is about 45″ diameter (8′-10′ from the ground).
• The largest hardwood I have ever milled is a 54″ diameter (20′ from the ground) Burr Oak.
New 100-year-old cherry; It is (no) lye!
Some woods stain great – some don’t. Oak, walnut and elm come to mind as the great ones. They stain easily and consistently, with no blotches or uneven color. On the other end of the scale are woods like maple and cherry, which are also consistent – consistently frustrating. Hard maple is the worst of the worst, with some of it taking almost no stain (I compare it to trying to stain a piece of glass) and other areas, like end grain, sucking up all the stain in the can. Anywhere that the grain simply changes directions is a spot for blotches to show up.
Right up there with maple is cherry. Although you can get some cherry boards to stain perfectly, many will look like a first-grader did it (and not the one first-grader that pays attention in class). The other problem with cherry is that it is usually expected to be at least medium-dark, which means the wood has to be darkened up somehow. I have a few recommendations for hard-to-stain woods, but for cherry, I have a trick. If you know it, don’t say anything yet.
This secretary was made from curly cherry and darkened with lye.
I don’t remember where I first heard of it, but I was told that lye darkens cherry. That’s right, lye, like the soap or Drano. I didn’t know anything about lye, so I did a little research. And, after using it many times, I can tell you that a little research is all I needed. It is amazingly simple and produces awesome results.
If I want a nice medium to dark cherry and don’t need to match a specific color, I will use lye before anything else. Lye is great because it does in seconds what would happen naturally in a very long time. It chemically changes the color of the wood, allowing all of the figure to show through without blotches. The new color created by the lye also goes below the surface to provide a measure of safety when sanding between coats of finish.
I use Red Devil lye (drain opener), which has apparently been discontinued. Lowe’s carries a crystal drain opener that is 100% sodium hydroxide (the active ingredient) or lye. I, however, have never used this product, so I cannot attest to its effectiveness.
To use the lye, simply mix with water. I use about two tablespoons to 16 oz. of water as a starting point. Test on a sample cherry board to see how dark it comes out – the change will be almost immediate. Add more lye to darken the color or more water to lighten it. To apply, use a nylon brush (natural hair brushes will melt away) to saturate the surface of the wood, keeping a wet edge and let it dry. That’s it.
Handle the lye mixture with caution and follow the safety instructions on the label. Specifically, wear rubber gloves and safety glasses, and make sure you have adequate ventilation.
Treat the wood as if you were using a water-based stain, by raising the grain before applying the lye. After the lye is dry, the wood can be finished and requires no treatment to neutralize the lye. I like to apply an oil finish before the topcoats to make the surface shimmer and really show off the magic of the lye.
No matter how you finish the piece, I think you’ll be amazed at how easily and quickly you can have a piece made from new 100-year-old cherry!
Sanding White Pine: Avoiding A Sticky Situation
I love, love, love Eastern White Pine. First of all, I love the way it smells – it can make even the nastiest of shops smell like new. I love the way it cuts –it cuts great on the sawmill and in the shop. I love that it’s lightweight – even, the widest boards are easy to handle. I love that is dries flat – most boards can just be run through the planer without any flattening. I love that it is soft – I can work it with hand tools and enjoy every minute of it. I love that when it starts to decay it gets lots of bugholes and blue-stain – it’s great for rustic work. I love that it makes great planer shavings – I want to roll in them just like the animals that use it for bedding.
There is, however, one major problem with white pine, especially air-dried white pine. It’s name is pitch. Pitch is the sticky transparent yellow goo that can ooze from the boards. In lumber that has been kiln-dried at high temperatures to “set the pitch”, this is less of a problem. As long as the lumber stays cooler than the temperature that the kiln was run at, the pitch will remain hard. But, once that threshold is passed, the wood starts to get sticky. And, since air-dried lumber hasn’t reached a very high temperature in its life, the stickiness is almost immediate.
Now, couple this setup with a large job and large boards and a lot of surface to cover with a power sander and you have a recipe for potential disaster. In fact, some air-dried white pine will be so sticky that you’ll start to wonder if there is enough sandpaper in the world to get through the job. There is, of course, a secret to working with white pine and an orbital sander. The secret is turpentine or mineral spirits.
I read somewhere that turpentine is made from pine trees, and I figured if it came from pine trees, it should be a great solvent for pine pitch, which also happens to come from pine trees – and it is. A rag dampened with either turpentine or mineral spirits will clean the pitch right off of a sanding disc or off of lumber where it has built up. To make it work in an almost automatic mode, I keep a sacrificial rag next to me soaked in the solvent and simply run the sander on the rag when it gets clogged. Just a few seconds running the sander on the rag makes the sandpaper look like new.
As I now get ready to sand a project that is all white pine, with wide boards and big, pitchy knots, I know the first thing I will do is get out the mineral spirits. Hopefully, this lumber cooperates and I won’t need to use it. Happy sanding to all!
For fun, I have some photos of the wide white pine (up to 20″) being used for shelves that inspired this post.
White pine was used for these closet shelves.
John Stevens and Scott use the bandsaw mill to resaw wide white pine for the cabinet backs.
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.