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have written before about The Heartwood School, which is focused on homebuilding crafts, particularly timber framing. Heartwood resides in the town of Washington located in the Berkshire Hills of western Massachusetts. It is run by Will and Michele Beemer. The school offers a full range of home construction and woodworking courses – including a SketchUp course for timber framers. There is now several Build Your Own: courses including Country Windsor Chair, Woodworker’s Workbench, Shavehorse, Pole Lathe and Heirloom Dovetail Toolchest. ALso added is an Advanced SketchUp Pro: Layout course.

The Heartwood School’s course list and 2014 schedule is shown below. For a complete course description go to http://www.heartwoodschool.com/coursefr.html and in the table’s second column locate the course of interest and click the link. For further information or to register contact Michele Beemer at 413/623-6677, www.heartwoodschool.com or request@heartwoodschool.com.

Two Week Courses:

July 7 – 18 Comprehensive Housebuilding

 

One Week Workshops:

April 21 – 25 Fundamentals of Woodworking
April 28 – May 2 Cabinetmaking
May 5 – 9 Stairbuilding
May 12 – 16 Build Your Own: Shavehorse
May 19 – 23 Build Your Own: Country Windsor Chair
June 9 – 13 Build Your Own: Workbench
June 16 – 20 Timber Framing
June 23 – 27 Scribed Timber Framing – Using Natural Forms
July 21 – 25 Finish Carpentry
July 28 – Aug 1 Cruck Framing
Aug. 11 – 15 Carpentry for Women
Aug. 18 – 22 Converting Trees to Timber
Aug. 25 – 29 Timber Framing
Sept. 8 – 12 Compound Joinery for Timber Framers
Sept. 15 – 19 Build a Skin-on-Frame Canoe
Sept. 22 – 26 Carve a 17th century Oak Box – Peter Follansbee
Sept. 29 – Oct 3 Build Your Own: Pole Lathe
Sept. 29 – Oct 3 Build Your Own: Heirloom Dovetail Toolchest
Oct. 6 – 10 Stairbuilding
Oct. 13 – 17 Fundamentals of Woodworking
Oct. 20 – 24 Cabinetmaking

 

Other Workshops:

April 7 – 9 Timber Grading (3-day)
April 17 – 19 Tangent Handrailing (3-day)
May 29 – 31 Hip and Valley Roof Framing for Carpenters (3-day)
May 29 – 31 Build an Outdoor Earthen Bake Oven (3-day)
June 2 – 4 Eyebrow Dormers (3-day)
June 5 – 7 Intro to SketchUp for Timber Framers (3-day)
June 6 – 7 Concrete Countertops (2-day)
June 30 – July 2 Traditional Raising and Rigging (3-day)
Sept. 4 – 6 Timber Frame Design & Joinery Decisions (3-day)
Sept. 26 – 27 Advanced SketchUpPro: Layout (2–day)

The Heartwood SchoolI have written before about The Heartwood School, which is focused on homebuilding crafts, particularly timber framing. Heartwood resides in the town of Washington located in the Berkshire Hills of western Massachusetts. It is run by Will and Michele Beemer. The school offers a full range of home construction and woodworking courses – including a SketchUp course for timber framers. New courses this year include Build Your Own: Country Windsor Chair.

The Heartwood School’s course list and 2013 schedule is shown below. For a complete course description go to the table below and in the second column locate the course of interest and click the link. For further information or to register contact Michele Beemer at 413/623-6677, www.heartwoodschool.com or request@heartwoodschool.com.

Date
Course
April 15-19 Fundamentals of Woodworking
April 22-26 Cabinetmaking
April 29-May3 Build Your Own: Woodworker’s Workbench
May 30-June 1 SketchUp for Timber Framers
June 1-2 Basic Concrete Countertops
June 7-9 Advanced Concrete Countertops
June 10-14 Build Your Own: Country Windsor Chair
June 13-15 Eyebrow Dormers
June 17-21 Build Your Own: Shavehorse
June 22-23 History of Timber Framing
June 24-28 Timber Framing
July 5-6 Build a Skin-on-frame Canoe
July 8-12 Converting Trees to Timber
July 15-26 Comprehensive Homebuilding
July 29-Aug. 2 Carpentry for Women
Aug. 12-16 Finish Carpentry
Aug. 19-23 Timber Framing
Aug. 26-30 Scribed Timber Framing
Sept. 5-7 Timber Frame Design & Joinery Decisions
Sept. 9-13 Compound Roof Framing
Sept. 16-20 Build Your Own: Pole Lathe
Sept. 23-27 Build Your Own: Heirloom Dovetail Toolchest
Sept. 30-Oct. 4 Stairbuilding
Oct. 7-11 Fundamentals of Woodworking
Oct. 14-18 Cabinetmaking
Oct. 21-25 Home Design for Owners & Builders


Will Beemer demonstrating the locking dovetail prop.I discovered the Heartwood School while attending the recent NWA Saratoga Woodworkers Showcase and wrote about it in my April 3, 2011 Chiefwoodworker’s Newsletter. All I knew about the school at that time is what I had seen at the show and read on its website. I sent the owner, Will Beemer, a copy of my newsletter and he wrote back inviting me to an active class. I took Will up on his invitation and visited Heartwood School on June 23, a damp and rainy Thursday.

Background

Shaping a tenon's seat with a spokeshave.Located in Washington, MA in the Berkshire mountains, Heartwood is run by Will and Michele Beemer. For the past 34 years Heartwood has been teaching students to design and build their own homes, mostly in timber frame construction.

Will has an extensive background in home design and construction, as well as teaching design and construction. He has taught at Cornell, Palomar College in San Diego and Colorado State University. He has written for Fine Homebuilding, Joiner’s Quarterly, Wood Design & Building, and Timber Framing. Michele is office manager, provides lunches for the students, is an on-site instructor and an author.

The first timber frame built by students houses the cafeteria, classroom, shop & library.Heartwood has a full range of courses in design and construction that run from April through October. Courses include energy efficiency techniques, fundamentals of woodworking, traditional cabinetmaking, building a workbench for woodworking, converting trees to timber and much more. They even teach SketchUp for timber frame designs.

My Visit

Checking the cut of an Eastern style tenon saw.Using my GPS I managed to find a small sign on a wooded road in Washington, MA. It said simply – Heartwood. I turned onto a paved and winding drive, which turned to a dirt drive that broke out into a clearing. The view reminded me of a childhood campground. Nestled in the woods to my left was a timber frame building with a sign over the door, once again announcing I had arrived at Heartwood. To my right were two long tents, open on all sides, like the tents used for a country fair. Under the tents, and protected from the rain, were eighteen students, an instructor and owner Will Beemer; all busily working away on 7” x 7” timber frame beams.

Tents set up to provide shelter from the rain.Trucks and cars were scattered everywhere, randomly parked under trees and I saw no defined parking area. As I sat there looking for a place to park my truck Will approached, introduced himself and welcomed me to Heartwood. He gave me a quick orientation introducing me to students, staff and showed me the shop, classrooms, library and kitchen. The latter rooms all resided in the timber frame building, which was the first building the students constructed when the school was opened in 1978. Will and Michele were not the owners at the time, though Will was an instructor. In 1985 they purchased Heartwood and have owned and operated it since.

"Get out of here with that camera so I can work!"Heartwood’s business model is simple and elegant. It brings together property owners who desire a timber frame home, barn, shop or other structure with students who wish to learn timber framing. Sometimes the owner and student are one in the same.

Everyone is busy but there is no panic. The raising is tomorrow.The first half of the business model is an owner who contracts with Heartwood to design, mill and erect a timber frame for about $30 a square foot. This includes frame only; finish materials, pre and post construction are the responsibility of the owner. If the owner’s site is more than 1.5 hours from Heartwood, trucking and other costs may be extra. Timber frame materials are rough cut Eastern White Pine, un-planed. Since Heartwood is a school for woodworkers and all work is done by the students, the owner must accept occasional constructions flaws, though Heartwood does its best to hide such mistakes. From my observation I doubt this is ever a real problem. The work I saw was top notch.

Now, that's a chisel!The second half of the business model is students. They come from all sorts of backgrounds and experience levels. Some have never held a woodworking tool before or never made a wood joint. Some are experienced woodworkers but who have no experience in timber framing. Many are hobbyists who want to build their own timber frame and attend the school to learn how. Still other are professional woodworkers or construction professionals who want to expand theirs skills and trade. I counted two women wielding chisel and mallet in this class of eighteen students.

Finished work ready to load on the trailer.Sometimes a class is held without a contracted owner. In that case a modest sized timber frame is crafted on speculation, though finding a buyer never seems to be a problem. The class I visited was building a studio for a contracted owner. Raising day was Friday, June 24th, the day after my visit. But there didn’t seem to be any schedule pressures, nervousness or frenzied activity. All seemed to be in control. There was a large stack of completed beams and the work-in-progress seemed near completion.

I believe this is a hand cut brace.My brother-in-law designed and built his own timber frame home and barn from hand hewn timbers. So I am familiar with the excitement of raising that these students had to look forward to. As I am writing this article on the 24th I am looking out the window at the rain coming down. Par for the course in the trades and a good lesson for the students.

Lots of mortises are needed for a timber frame construction.My primary interest in woodworking is furniture crafting. The interest I share with these students, however, is hand tools and joinery. The dovetails, mortise and tenons I use in my joinery are not all that different from those used in timber framing with the exception of size (I will post a follow-on article on one unique and interesting joint used by these students). Most of the joinery these students use are cut by hand with a combination of handsaw, chisel, mallet, spokeshave and drawknife. To be sure, those joints are larger than one would use in a furniture shop, but they are used in very similar ways.

How's that for a mortise bit?In my shop I use a power mortiser and I was surprised to see the timber framer’s equivalent sometimes used by the students. It is driven by electric motor and plunges in to the timber much like a plunge router would. However, instead of a square chisel and drill bit, the cutting blade is three – stacked side by side – chain saws. The beams used are 7” x 7” and the tenons are 1 ½” thick. So I suspect the chains are designed to be 1 ½” in width when stacked, and long tenons are formed with Looks like instruction on how to use the power mortiser.repeated plunges, though I failed to ask about this. A fence can be adjusted to place the tenon the appropriate distance in from the edge of the timber. It appeared to me that the “blade” could be plunged a little more than eight inches for a through mortise, or adjusted less deep for a stopped mortise.

The dovetailed tenon half of the locked mortise and tenon joint.Most of the mortises I saw were hand cut with a mallet and chisel. A couple of students were being instructed in the use of the power mortiser. So this may have been the one signal that the scheduled raising was requiring the use of more rapid methods, though once again I failed to enquire about this.

Friendly conversation over Michele's lunchtime meal.I was struck by the accuracy and smoothness of finish of the hand cut joints. Obviously not the kind of finish you would find in hand crafted furniture, but still I found myself needing to wipe my hand across the joints and marvel at the smoothness. I picked up a few tools and checked out the sharpness and found myself approving what my hand felt. As I studied the joinery I could see the light pencil lines that provided guidance for hand cuts. All in all I could relate to the work of the students and I even had a feeling of wanting to join in. That’s when Will came out of the timber frame building and yelled “Lunch”.

Lunchtime at Heartwood

Michele at work in her kitchen talking to the students.When Will invited me to visit he said I should plan to arrive at noon and join he and the students for lunch. I had read about Michele’s fine cooking on the Heartwood website and I was eager to sample the food. My eagerness was aided by the fact that I was just plain hungry. Hunger is a feeling I get if I spend too much time watching others hard at work. So I joined the rush to the dining room.

A 1 personpower drill press. Notice the dual crank.Dining at Heartwood is cafeteria style and all the food is home cooked. I had a soup, sandwich and crab salad. If you are a New Englander there are three chowders of choice: clam, seafood and corn. I love all three and I thoroughly enjoyed Michele’s corn chowder and crab salad.

Over lunch I talked to several students I The classroom is on the second floor across from the library.sat near. One was from a town not far from where I was born and raised and we shared news of that area. I learned that students stayed in B & Bs, hotels, friends homes or even commuted to Heartwood. Those I talked to came from all over New England and New York, though I suspect Heartwood draws from a much wider area as well.

The comfortable portion of the library. There are additional bookshelves out of view.After lunch I took more pictures, including the shop, library and classroom. The library has a wonderful collection of books on timber framing, general construction techniques, drawing, energy efficiency and many other home building related topics. If I go back to Heartwood I would like to spend some time in this library and get some titles for my own collection.

I said my goodbyes and thanked Will and Michele for the visit and lunch. I left feeling I had visited a woodworking school I could really enjoy and learn from. And I left with more questions than I had answers. So one day I hope to go back and talk with Will in more depth – and of course have another lunch.

Heartwood Update

I'm guessing this is a vertical support post with both mortise and tenon joinery.I spoke to Michele on Friday late. She and the class had just returned from the raising. All went well and the class finished the raising early afternoon. Though it rained in my area the rain held off at the building site. The raising marked the end of the class. Eighteen students were going home newly proficient in timber framing. It doesn’t get much better than that.


Susan Fiske, ProprietorI am fortunate to own 5o acres of forested land and live in an area where I can fell trees and hire local sawyers to cut them into rough lumber. That is how I get much of what I use in my shop. However, that strategy limits me to local species and generally narrow and four quarter stock. When I need other species, exotic species or larger stock I first call Sue to see if she has what I need, and she usually does. When crafting fine furniture, as important as woodworkers skills are to its final results, is the quality of the wood he/she uses. For this reason it is important to have a source you can trust and whose products are of the highest quality. That is why I turn to Forest Products Associates. That and the personality known as Sue.

Bolivian rosewood, waiting to be graded and shelved.Forest Products Associates has been a family owned business for over 60 years, located on the outskirts of Greenfield, Massachusetts. Founded by Lee Fisk, today it is run by Susan Fiske. Sue lost her mom a few years back and her dad remarried. He now lives in Texas and is not active in the business. Sue’s clientele ranks in the four thousand range and growing. Her customers range from hobbyists like me to professional cabinet makers, contractors and architects.

Shelving for Graded Lumber accessible on the first and second floor.When I first started buying lumber from Sue she had four or five sheds, though one was the primary shed. I believe one or two may have been used for drying lumber. The sheds with dried lumber were open to the weather, protected only by a slanted roof, sides and back. The office was a small, cramped trailer with two wooden steps. Climbing the steps and opening the door at the same time took a little skill. The office fit about two people; Sue and a customer.

The fork lift always stands ready to access a pallet of lumber not yet graded.In the winter it was a colds days task just to sort through lumber for a project; a task I never looked forward to. On these January days even the office seemed large and cozy. I have no idea how Sue made it through those entire days of winter, day after day, and remained cheerful and helpful whenever a customer arrived. Sue always has a smile on her face and is willing to spend as much time as you wish. Her knowledge of wood is endless and I have often picked her brain about its characteristics.

Lumber Not Yet Graded and ShelvedSeveral years back Sue built the current shed. This one is huge, closed in, concrete floor and well organized storage shelves. Shortly after it was completed a storm reduced a third of it to rubble. So Sue did what she usually does; she smiled and rebuilt it – but even better. It now has a spacious and comfortable front office. She is very proud of the sign that hangs over its door with the name of her business, and the little sign that announces Office. I suspect the door is seldom closed.

Ash Billets - Want to make your own baseball bat?Sue is one of those rare business people who really want the customer to be happy with her product and she maintains a quality control level also rare in business today. On many occasions she has helped me sort for the lumber I needed.

Sometimes she would steer me away from certain board(s) based on my description of the piece I was building. She would say “there is nothing wrong with that board, but if you are going to use it on the front of that hutch we can find you better grain patterns” or something of the kind.

Curved live edge slabs. Those directly in front are apple. Those behind are cherry.Sue's OfficeI live about one hour from Forest Products Associates, so I always call Sue first to see if she has what I need. She carries a cell phone at all times and is always available. Sometimes the lumber I want is still on a palette and not yet graded. She has always offered to have it open for me by the next day, and if necessary grade it for me as I select it.

8/4 black walnut slab with beautiful feather figure. These days, because her dad has moved and is no longer active in the business, Sue’s responsibilities have grown and she has hired staff to help. She needs to spend more time in the office or on maintenance projects. So when you call you may get a staff person, but rest assured they will be every bit as helpful as Sue. And you can always find Sue somewhere there, and she is always willing to talk and brighten your day.

Four quarter purple heart. First number is Bd Ft and lasst is length.Sue’s products have grown over the years both in size and variety. She now has a much larger variety of exotics and large pieces for custom tables. She also has larger inventory of wider and thicker stock. Her business has grown in spite of the economic downturn.

For more information on Forest Products Associates, check out their web site: http://www.forestproductsassociates.com/index.html. If you live near or within reasonable driving distance of Greenfield, MA you will find Forest Products Associates a reliable, quality supplier of rough cut hardwood. Check them out. Give Sue a call or stop in.


Wood Expansion Calculator 1.0 Sample Input Page Wood Expansion Calculator 1.0 is now available. The picture at left shows some of the major changes.

When using the Relative Humidity input option the temperature can be specified in either Fahrenheit or Celsius. The other temperature scale will be calculated and also displayed.

When choosing a Calculation Mode input boxes appear for receiving user specified dimension inputs. These can be supplied in either Imperial (US) or Metric units.

Metric dimensions require one, and only one, unit; either m, cm or mm. The following are the only valid inputs:

     i m
     i cm
     i mm
     d m
     d cm
     d mm

Where i is an integer whose first digit cannot be a zero. Where n is a decimal number and the first digit cannot be a zero unless the decimal point is immediately to its right. In fact, a decimal number less than 1 must begin with a zero such as 0.967 cm. Note the space between the dimension and its unit. This is required.

Imperial dimensions may require more than one unit, for example 3′ 7 1/64" is a valid input. The following are the only valid inputs:

     i"
     n/d"
     i n/d"
     f’
     f’ i"
     f’ n/d"
     f’ i n/d"

Where i, n, d, and f must be non-zero integers who’s leading digit also is not a zero, e.g. 0123 is invalid. Note, unlike the Metric units, there is no space between the dimension and its unit; in fact a space will create an illegal entry.

Wood Expansion Calculator 1.0 Sample Output Page Consistent with supplying the alternate units results as was the case with temperature, the output will show results in both systems of measurement. The type supplied by the user will appear first and the alternate second. A sample results page can be seen at right.

A number of bugs were fixed in this release but do not materially change the functionality.

There are future changes planned for Revision 2.0 that include but are not limited to the following:

  1. Provide the capability for users to supply their own Regions and corresponding EMC values.
  2. Provide the capability for users to supply their own Species and corresponding shrinkage factors.
  3. Provide memory so that user settings and inputs are restored when next the tool is opened.
  4. Strengthen the help messages, especially for the dimension inputs, and add more help features.

If you have any suggestions please pass them along in a comment to this post (preferable because others can see them) or forward them in email.

Download Wood Expansion Calculator here.


I have written a number of blog posts dealing with techniques for handling the seasonal change of wood movement and I am sure to write some more in the future. If you have crafted much in the way of furniture, or other pieces constructed from rough wood, you know you have to take wood movement into account in design. Failing to do so will ensure cracks and structural failure. If you do not believe this let me point you to two very good articles outlining the problems and solutions. First, an article that appeared in American Woodworker, 1993 issue number 34. The title is Coping With Wood Movement – How to Build Furniture That Won’t Crack or Split, pages 38 – 43 and written by Jim Cummins. If you don’t have this issue you can find it on the internet by clicking here.

The second article is titled The Shrinking and Swelling of Wood and Its Effect on Furniture by Carl A. Eckelman. I will make this and other references available via Adobe PDF download at the end of this blog. Both of these articles outline specific construction situations, the effects of moisture and resulting wood movement on them, and techniques to avoid the problems that can arise. In both articles the author points out the importance of knowing how much movement to expect and that is the focus of this post.

Wood Movement – The Basics

SEM View Of Poplar - Photo Courtesy Of N.C. Brown Center, SUNY Let’s start with a short explanation of why wood moves. (For a comprehensive coverage of this topic I have listed a number of articles and books at the end of this post.) When wood is alive and green it is made up of soda straw like vessels that tend to run end to end along the length of the tree. These vessels are made up of thin walls consisting of specialized cells. (See the scanning electron microscope photo of Poplar at left.) Both the vessels themselves and the cells that form their walls contain water. When the tree is cut and sawn the vessels begin to lose water and continue to do so until all the water is out of the vessels. At that point the cells that make up the walls still contain moisture. This point is called the Fiber Saturation Point or FSP. It is the point where the tree has given up all its “free water” but the cells are still saturated with “bound water”. This point is very similar in most trees and represents a point at which the tree (lumber at this point) still has a moisture content of approximately 30%. (Moisture content is the ratio of water weight contained in the specimen to its oven dry weight, i.e. no water weight. Many trees, when live, have moisture contents greater than 100% which means that water accounts for more the half its live weight.)

The drying process from green moisture content to FSP, while making the lumber less dense or heavy, does not cause any shrinkage and in fact the lumber is still in its weakest state when it reaches FSP. As the tree (lumber) continues to dry from FSP to 0% (called oven dry) it gives up bound water from the cells, shrinks and becomes stronger. The shrinkage is quite linear from FSP to oven dry and the total shrinkage, expressed as a percentage, can be measured in three dimensions: radially, tangentially and longitudinally. Longitudinal shrinkage, which occurs along the length of the lumber in the direction of the grain, is very minimal and is generally neglected.

Flatsawn (Plain Sawn) Versus QuartersawnTangential shrinkage occurs along a line tangential to the tree’s growth rings and radial shrinkage occurs along a radial from the center of the tree. These two factors are called tangential shrinkage factor (expressed in percent) and radial shrinkage factor and can be related to two common types of lumber: flatsawn and quartersawn respectively. Tangential shrinkage is usually about twice as large as radial shrinkage but they each vary widely from species to species. In real life no lumber is cut exactly quartersawn or exactly flatsawn (also called plain sawn). As a craftsman you have to make a judgment call. If in doubt you might want to consider treating your lumber as flatsawn because that would be worse case.

Map Of Regional EMCs For JanuaryOK, so we know that wood shrinks as it loses water from FSP to oven dry. But the reverse is also true; it expands as it takes on moisture from oven dry to FSP. So what makes wood give up and take on moisture? Its environment. Relative humidity and temperature, and both change throughout the year, usually from dry air in the winter to moist air in the summer. If lumber sits long enough in a given environment it will reach equilibrium with that environment. Suppose for instance that the average temperature and relative humidity have been 80 degrees Fahrenheit and 70% relative humidity for the past two months. It is likely that lumber stored in this environment will come to equilibrium at a moisture content of 12.9%. Clearly higher than one would like if one intended to build a piece that would reside in Arizona. This is why we bring lumber into our shop and let it sit for a few weeks; to let it reach equilibrium.

Map Of Regional EMCs For JulyMost homes do not have humidity controlled environments and are subject to seasonal moisture changes. There have been a number of studies that have measured the outdoor monthly averages over the course of many years. Through the use of computer models, these studies produced maps and tables of indoor seasonal ranges by region of the country. The Department of Wood & Paper Science at North Carolina State University produced such maps in 2003 which you will find by clicking here. These values are called Equilibrium Moisture Content or EMC and represent the moisture environment a piece of furniture would be exposed to, on average, for each month and by region.

Wood Expansion Calculator

An Opening Centric Analysis Of Cherry In The Massachusetts Interior This brings me to the real topic of this post – a SketchUp Plugin tool called Wood Expansion Calculator. I created Wood Expansion Calculator to estimate just how much expansion and shrinkage you might expect in a given structural situation. I developed this tool because I have for years used a stand alone application called Wood Movement Master by Kite Hill Software which does precisely this. You have probably read some of my articles where I used this tool. Unfortunately, it is no longer available or supported by Kite Hill Software or its developer. I decided to pick up the gauntlet and provide the same capability in a SketchUp tool. So here it is: Wood Expansion Calculator ZIP File.

One note of caution. In my professional life (I am now retired) I was an electrical engineer and engineering executive. I started my career when CAD tools were nonexistent and you had to figure things out with paper, pencil and a slide rule. The advantage of this was that you developed a close feel for what you were designing. You knew the expected behavior intimately. Years later, when I was an engineering manager and CAD tools were ubiquitous, it drove me nuts to see a young engineer model a circuit, run the tool and take the results as Gospel. He/she had no feel for, or personal intimacy of the expected results. Don’t use this tool that way. It is meant to give you a quick, efficient, and yes accurate result so long as the input and assumptions are correct. If, for example, the temperature is 100 degrees Fahrenheit today at 90 percent relative humidity, and expected to be 30 degrees Fahrenheit and 10% relative humidity tomorrow, don’t expect wood stored in this environment to respond to that change no matter what this tool might indicate. Moisture takes time to enter or leave a specimen; that’s what equilibrium accounts for. So use judgment as well as the tool.

The tool itself is quite simple to use, and has Help notes for each input. To install the tool use WinZip to extract the one Ruby file and one folder to the SketchUp Plugins folder on your system. When you open SketchUp you can access the tool via Tools/Wood Expansion Calculator or go to View/Toolbars and check Calculators for a toolbar and icon (a tree). What you need to know to use this tools is the stocks current moisture content (best to use a moisture meter to measure this), the region of the country where you expect the final furniture piece to reside, the wood species, the stock type (flatsawn or quartersawn) and the construction situation you want to analyze (board centric, opening centric or breadboard end).

A Printer Friendly Results Of An Analysis If you don’t know the stocks current moisture content you can use a Relative Humidity and Temperature mode to calculate it. But be careful. Consistent with two paragraphs ago be sure to use average temperature and average relative humidity of the environment the wood has resided in for a period of time long enough to reach equilibrium. Do not use seasonal or daily maximums. The wood’s moisture content will not respond to fast or temporary changes.

One other note; board centric, opening centric and breadboard end are not a specific construction method but a representative method. For example, opening centric includes drawer fronts that fit flush in an opening, but could also mean a panel that is framed to make a door. Breadboard end could represent any cross grain situation such as a mortise and tenon. Don’t let the labels limit your use of the tool. Understand what is being analyzed.

This tool currently works only with Imperial or US measurements.

For example 3′ 7 1/64" is a valid input. More precisely, the following are the only valid inputs:
i"
n/d"
i n/d"
f’
f’ i"
f’ n/d"
f’ i n/d"
where i, n, d, and f must be non-zero integers who’s leading
digit also is not a zero, e.g. 0123 is invalid.

In the future I will expand it to accept metric measurements. The region table is the contiguous US only. In the future I hope to get data for other regions of the world. But you can still use this data by selecting regions that you know are close to environmental conditions in your area. Also, in the future are plans to let the user build their own environmental tables or to add their regions to the existing table. Lastly, I plan to add persistence to the tool so that it remembers the last set of conditions analyzed and uses them as the starting point when the tool opens.

Please report all bugs directly to me, and include the conditions that resulted in the bug. Thank you in advance, and I hope this tool serves you as much as Wood Movement Master has served me in the past.

Related Reading

Centennial edition of the Wood handbook : Wood as an Engineering Material. This is an excellent reference book. You can download individual chapters in PDF format. Chapter 04: Moisture Relations and Physical Properties of Wood is particularly pertinent to this blog post.

Understanding Wood – A craftsman’s Guide To Wood Technology by R. Bruce Hoadley is a book that ought to be on the bookshelf of any serious woodworker. Chapter 6: Water & Wood is particularly appropriate to this subject, but the entire book is directed at the woodworker.

The Shrinking and Swelling of Wood and Its Effect on Furniture by Carl A. Eckelman was mentioned at the beginning of this post. It is an excellent article on designing for wood movement.

Download Wood Expansion Calculator Here


On my most recent project, the American Chippendale Mirrors discussed in my last post, I was forced to choose between using a table mounted router or a shaper. Specifically, was how to shape the picture frame molding which was complicated by the use of tiger maple hardwood.

Tiger maple is notorious for tear out whether hand planing, jointing. thickness planing or shaping. I have described in this blog numerous times how I thickness plane the final 1/8” to 1/16” of tiger maple using my Performax Pro 22-44 for just this reason.

CMT 855.902.11 Traditional 1/2” Shank Router Bit The bit used to shape the molding in this project was a CMT 855.902.11 Traditional 1/2” shank bit. Its overall cutting length is 1 5/8” and its overall diameter is 1 1/16”, rather small for even considering a shaper.

The primary decision making criteria between using a router and shaper is the bit diameter. Bit RPM being equal, large diameter bits have a higher tangential velocity compared to small diameter bits. Large diameter bits remove more material requiring more horse power. This is where routers and shapers differentiate themselves (portability is another but not applicable when comparing table mounted routers to shapers).

Routers generally spin at higher RPM, typically 10,000 to 21,000 RPM and range from fractional horsepower to 3 1/2 horsepower. Hence they are useful mostly for small diameter bits. Shapers generally have two or three speeds to select from, usually 8,000 and 10,000 RPM and start at 2 horsepower and range to in excess of 5 horsepower. Hence applicable to large diameter bits.

RPM are directly comparable, but not all horses are equal; a 3 1/4 HP router is not equal to a 3 HP shaper, the latter being much more powerful. I should also mention that shapers tend to be much more hazardous than routers, so special attention to safety is required.

Molding Picture Frames On The Shaper This all being true one would normally mount this bit in a table mounted router and shape away. I started that way and quickly realized I needed to consider the shaper. Even though I was using a 3 1/4 HP variable speed router with speeds selectable from 10,000 to 21,000 RPM I couldn’t achieve a tear out free finish, no matter how many light passes I made. I put the same bit in my shaper and selected 10,000 RPM and discovered I could make tear out free finishes if I cut the molding in five light passes and proceeded slowly and smoothly on each pass. I can’t explain this rationally but I can demonstrate it quite clearly. If someone has a technical explanation I would certainly like to hear it.

This is not the first time I discovered this about tiger maple. In fact, on almost every project requiring tiger maple molding I end up on the shaper. I always try to avoid the shaper because of the long setup time required, but in the end I succumb. So this time I committed to design a fence for my shaper that will allow fast setups, flexibility, and safety. Designing such a fence may take a while but will pay large dividends in the end.


Two StoolsIn a previous blog titled Play The Hand You’re Dealt I discussed a strategy for acquiring and using inexpensive rough lumber. My woman friend and partner, Willow, put that strategy to use in building the foot stools shown at left.

But first a little background. In the fall of 2003 Willow was pondering what to give our grandchildren for Christmas. Our children and their families visit us for a few days each Thanksgiving. It is my favorite holiday of the year. During that 2003 Thanksgiving visit one of my granddaughters wanted to join Willow in baking pies. We have a Shaker style step stool we keep handy just for such occasions. Our granddaughter used it to reach the counter so she could join in the fun. This particular type of Shaker stool can be unstable if not placed against something to keep one from stepping too close to the back and going beyond the stool’s center of gravity. My granddaughter did just that and fell to the floor, thankfully unharmed. Willow decided there and then that grandchildren needed a more safe step stool design. This, she decided, would be their Christmas present.

Christmas StoolThe job of designing one fell to me. The Shaker stool, stability aside, was light and perfectly suited for the desired purpose. It was made of pine which made it light so that kids 3 years of age could pick it up and move it into position. All it needed was legs that splayed to keep its load within its center of gravity. I drew up some plans and provided Willow with some poplar. She set about making four stools; one for each of our three grandchildren, and one for our college aged daughter for use in her dorm. Each stool was painted, including their name in a contrasting color. They were a big hit. Each time we see the kids grab a stool and move it into place we get a warm feeling, because we know they will have those stools well into their adult life. At right my grandson is sitting on his stool while opening additional gifts he received that year.

One Stool Showing DetailsBack to the present. Willow has wanted to make a few more of these stools to keep at our homes in Worthington MA and Eastham MA on Cape Cod. So recently she again asked for the drawings and some reject lumber. I have a stack of black cherry that is loaded with pitch pockets and is a mix of sapwood and heartwood. It is structurally stable and when finished with a natural finish is quite attractive. I often use it for the backs of furniture when the back is not visible, such as the back of a chest of drawers. This time Willow built three of them. Being made from cherry they are quite a bit heavier than the originals, but fortunately our grandchildren are older and able to handle them.

The design is simple. The end pieces are a trapezoid which provides the stability. The cross brace is attached to the ends with biscuits. The top slats are attached using long wood screws with large thread. All joints are also glued. The top slats have a handle shaped into the slats so the stool can easily be picked up with one hand. The screws are countersunk and filled with wood filler to provide a contrasting image.

Seven stools later we and the grandchildren still enjoy this handy little home tool. If you are strapped for a gift for someone of any age, think about a foot stool. It takes only a day to build several, they are very useful in the home, they will serve the recipient throughout their lifetime and they are likely to be passed on to other family members. Not to mention, it is a good way to use otherwise scrap lumber.

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I am not a famous poker player, in fact I don’t play poker at all. But if I were a famous poker player, I might say something quotable like – "In poker there is no no such thing as a bad hand, only bad players". However, I am a woodworker, so my famous quote will have to be – "In woodworking there is no such thing as bad wood, only bad woodworkers". Now I don’t mean to offend anyone, so in this politically correct world I should probably revise my yet to be famous quote to "In woodworking there is no such thing as bad wood, only budding woodworkers". Ahhhh! With that settled I can now write this article.

Hardwood is rather expensive, generally costing from $4.00 a bf to $10.00 a bf, and averaging around $6.00 a bf. I don’t like paying that premium, I much prefer to spend money on tools. So I have a strategy that works for me – and maybe for you too.

If you live in the country there are bound to be local sawmills, often one person hobby sawmills. Find out where they are and cultivate a relationship with the owners. I guarantee you, if you spend some time at it, you can get the best hardwoods for about $2 a bf on average.

Black Walnut stickered to air dry.Be ready to help someone cut wood. They will pay you in wood. Keep an ear open for the little old lady who wants that black walnut tree cut down in her front yard (see my website for just such an opportunity – Wood Sources). She probably doesn’t know or care about its value; she just wants it gone before it falls on her house. The picture at left is of black walnut "firewood" I rescued.

Be ready to trade a custom piece for a several hundred board feet of lumber, or help someone out with a built-in in exchange for lumber. Country folk know how to barter. Much of what they have they obtain through bartering. Join in the bartering and get your favorite hardwood cheap.

If you live in the suburbs or cities, be prepared to drive an hour or two. If you buy 50 – 100 bf you are saving $200 – $400 and that will certainly pay for the gas even at $5.00 a gallon.

Plan ahead. When you buy rough lumber you may have to dry it, or at least let it acclimate to your shop conditions. Don’t expect to purchase it on a Friday evening to begin building on a Saturday.

Rough cherry with split ends.Now, this strategy works only if you work at it, AND you are willing to work with the lumber you are can get your hands on – or should I say "Play The Hand You’re Dealt" which is the title of this article.

When you deal with hobbyist sawyers or private people you can’t expect to get quality-level-one lumber. Often these people don’t know how to treat the ends of green lumber to keep them from splitting. Seldom do they know what thickness to cut green lumber to end up with 4/4 dried material. Many don’t know the difference between plainsawn and quartersawn. You have to look beyond these problems and see the wood for it’s potential.

Cherry door sans finish.My brother and sister-in-law asked me to build them some maple cabinets for their laundry room a few years back. I didn’t have maple in my stock at the time so it would have cost about $6.00 a bf to purchase. I told them I could do it with cherry for about $2.00 a bf. They jumped at the opportunity. I started with the wood shown above right. Notice the split ends. This would be low quality cherry if purchased from a retailer. After careful selection and preparation I was able to get sufficient cherry to produce the face frames and doors for the cabinets. See a completed door at left, shown before finishing is applied.

Low quality tiger maple and cherry.I am always on the lookout for "firewood" to rescue. The second floor of my 30′ x 30′ shop is cluttered with piles of assorted wood. Some of it looks almost unusable. Take a look at the picture at right. You will see a pile of tiger maple in the back corner. It is twisted, warped, bowed and generally unattractive. Worse yet look at the pile of cherry in front of it with pitch pockets and bark on the edges. What could possibly be the use for that?

Cherry with pitch pockets.I built a Shaker inspired "Cherry Chest of Drawers" for my woman friend some time back. You can find the finished piece in my Gallery. I needed wood for the ship lapped back. Since the back would never be seen, the wood merely needed to be structurally sound. The pieces could be random width but all the same length. The cherry in the pile shown above right fit the bill perfectly as shown left. Notice the pitch pockets. They actually add something to the back.

TTiger maple table top.he tiger maple "firewood" shown above right I acquired through my brother-in-law who worked for a sawyer who supplied wood for pallet construction. I got this 200 bf pile of tiger maple for $1.50 per bf (the pile was larger when first stickered). I have been waiting a year for it to dry so I could see what it would look like in a finished piece. Well, my most recently completed project is a 30" T x 30" W x 72" L table for my office. I built it out of four species of wood. Cherry was used for the table legs and aprons. The drawer bottom was birch, its sides and back tiger maple, its front blistered maple and the drawer opening has a beading of black walnut. The top, shown right, is tiger maple, the very same tiger maple shown in the picture above.

Bottom of table top.This rough cut tiger maple was fortunately cut to 1 1/8" when wet and dried to about 1 1/16". Because it was twisted, warped and bowed, I had to plane it very carefully and with a watchful eye to be sure I got 3/4" finished thickness out of it. In fact, one board didn’t quite make it, but I used it anyway, placing it bad side down. The glued-up table bottom is shown left with this "flaw". It actually adds something to the piece. Two hundred years from now an antique dealer will point it out to a customer as evidence of a hand made piece. You can see the finished piece titled "Office Table" on my Gallery page.

The moral of this story is, don’t pay high prices for wood; buy tools instead. You can get all the "quality" hardwood you will need if you just keep your eye open for firewood, cultivate local sources and are willing to barter. The selection and preparation will take a little longer and you will have to train your eye to "see" the opportunities in lower quality rough lumber, but it is well worth the effort. And it is an added thrill, at the end of a project, to look back at pictures of the starting material. So keep a photo log of your stock and work. It adds to the "Joy of Woodworking".


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