Tag Archives: wood

Gabriel Janka and the Hardest Tree in the World.

By   14 Jan 2014

What makes a hardwood a hardwood, a softwood a softwood, and are hardwoods actually harder than softwoods?

     Believe it or not, the terminology has nothing to do with the density of the wood fibers (hardness).  Hardwoods are simply those species that are deciduous trees, and softwoods are conifers (evergreens).  It’s just that simple. However, simple seems to rarely remain simple.  While it is GENERALLY true that hardwoods tend to be harder than softwoods, the actual hardness of the wood may not follow that tendency.  For example, remember those Balsa wood bridges we made in science class in middle school?  Balsa is a deciduous tree, and therefore a HARDWOOD, as is the softest known wood specie, Cuipo (aka BongoHameli or Macondo).  Yet, they are considerably softer than, say, the softwood Douglas Fir that constitutes your average 2×4.

How does one measure such a thing objectively?

     Around the turn of the last century, an Austrian-born emigrant named Gabriel Janka (1864-1932) was employed as a researcher for the Forest Products Lab of the US Department of Agriculture.  His task was to objectively and scientifically measure the hardness (and therefore, durability and structural quality) of the lumber products coming out of America’s forests in that day.  He came up with a methodology for testing samples of these wood species that allowed objective comparison.  Janka’s hardness test consists of an instrumented mechanical press driving a .444-inch steel sphere (ball bearing approximately the size of a .44 bullet) into the surface of a between 1- to 2-inch thick sample.  The amount of force required to press the sphere 1/2 its diameter into the sample’s surface is the Janka Hardness Rating.  Janka’s hardness test method was adopted as the industry standard in 1906, and is measured in units of pounds in the US, kilograms in Europe and Newtons in Australia.  Though, a rating is commonly referred to in a simple unit of Janka, i.e. “Cuipo is 22 Janka, Balsa is 100 Janka and Doug Fir is 660 Janka”.

Janka Hardness Test


     The hardness rating depends on the direction of the grain.  A hardness test on the face of a sample is called a side hardness rating, whereas a test on the end grain is called an end hardness rating.  Unless otherwise noted on a Janka hardness chart, it is assumed that a chart is side hardness.  Also, the hardness rating in the chart represents an average of a huge sample size for that particular species, to mitigate the variability of hardness within the trunk of the same tree, i.e. heartwood is harder than the “live edge” growth ring.  The standard deviation is unique for each specie’s sample set, but they all median around 20%, so the accepted rule of thumb is that a number from the Janka Hardess Chart is +/-20% for that specie.

“Great, you told me some scientific history.  What use is it?”

     The straight Janka Hardness Rating for a specie of wood is probably useless in and of itself.  I seriously doubt anyone will use that number in some sort of engineering calculation.  The Janka chart allows us to compare the relative hardness of various woods during design and/or fabrication decisions.  For example, on a current client project in the Wood Works, we edged Birch ply panels in Black Walnut to get a nice light-dark contrast.  Black Walnut is 1010 Janka, and Birch is 1260 Janka.  This means that when sanding, the Walnut will abrade away faster than the Birch, which is good to know when one is trying to flush up the trim without sanding through the veneer of the ply!  Also, the flooring industry uses the Janka chart to determine material suitability and durability of engineered wood flooring products.

   You can find the Janka Hardness Chart on Wikipedia, or here in our K-base:  Janka Hardness Chart.  Oh, and the Hardest Tree in the World?

Australian Buloke… 5060 pounds-force!!

Mike @ Doobly-Do Wood Works

Merry Christmas! Where’d the year go?

By   29 Dec 2013


As we draw yet another year to a close, the Doobly-Do-ers would like to take this opportunity to stop for a moment, catch our breath, and reflect back on a year flown by.  This time last year, our online adventure was only a month and a half into its infancy, and the learning curve was nearly vertical.  While creativity, skill, dedication and decades of experience in the wood shop are a boon for business, it does not follow that those same attributes would easily translate to the world of “Online” and “Social Media”.  Again, I hear the Grand Doobly’s voice gruffly resonating in my head:

“If erring is human, wait ’til you ‘go digital’.”  — The Grand Doobly

Okay, so we weren’t as “on fire” in cyberspace as we were in the shop this year.  I concede that.  Our last post was… MARCH?!?  Wow.  We are painfully learning that with great products comes rapid growth… in demand.  With increased demand comes all kinds of demons… schedule crunches, capacity shortage, and the arch-nemesis of all small business… under-capitalization.  Just look what we’ve built this year:

  • Water-balloon hurling catapult;
  • Massive cherry bookcase with a sliding library ladder;
  • Piano repair;
  • Split-level entertainment credenza;
  • Full-wall bookcase with window seat and lighting;
  • Router table;
  • Router lift;
  • Custom kitchen cart;
  • Child’s art easel;
  • Award plaques;
  • Trophy plinths;
  • Military challenge coin racks;
  • Table saw upgrade (Work In Progress);
  • Baluster railing and gates (Work In Progress);
  • Compact all-in-one desk/entertainment center (In Design);
  • Media storage drawers (In Design);
  • Serving cart (In Design);
  • Jib crane (In Design);

I know, I know; where’s all the pictures and the videos and the blogging and the social contact documenting it all?  Could it be that we were really busy?  Could it be that we just suck?  Could it be both?  The World may never know.

All self-flagellating humor aside, the Wood Works has really been humming, especially at the Christmas time of year.  (Keeping Santa on schedule and properly supplied is no easy task… don’t tell The Grand Doobly I said that out loud.)  Our New Year’s Resolution is to improve considerably in the ‘online engagement’ department, so keep a sharp eye for more to come from your favorite Warped wood smiths.  We here at Doobly-Do Wood Works hope you had the Merriest of Christmases, and would like to wish you the Happiest New Year!

Mike @ Doobly-Do Wood Works


Busy! by Doobly-Do!

By   17 Mar 2013

Hello again, Friends!

I apologize for our long absence from the communications array.  The Wood Works has been hopping lately, with our biggest CBTO project yet coming to completion and another just like it about to kick off.  It is truly challenging to keep up with everything the Grand Doobly tasks us to do, but there is nothing like finishing a project and seeing the client smiling.

With the Woody Bookcase finished, our next project is the Morgan Bookcase… considerably smaller, but with a few more custom details that we think you’ll find interesting.  Make sure to visit the gallery often for updates and to see the progress.

Mike @ Doobly-Do Wood Works

Merry Christmas! …and a Happy, Hopeful New Year!

By   22 Dec 2012

Christmas is always an exciting time around the Wood Works, but with our efforts to get with the times and get digital, it is even more so this year.  We’ve started this website and fought (and are still fighting) our way through all the growing pains that brings, gone through a thousand photos of our previous works to pick the best to share, and then lost the digital camera in which they were saved.  We spend a lot of time with our master smith staring at us in gruff, silent disbelief.

“To err is human, but to really screw things up you have to ‘go digital’.”  — The Grand Doobly

All humor aside, we have been hard at work developing product lines for market via the Internet.  We have a seemingly endless font of ideas, all fun and unusual, from old-fashioned toys to holiday decorations to haunted house props to displays for your keepsakes, even to water-balloon siege engines for ultimate water-fight domination.  We are excited in anticipation of these launches and all the rest of the good things to come in 2013.  Now if we could just get that darn shipping module to work in the shopping cart…

God Bless, and have a Merry, Merry Christmas!

Mike @ Doobly-Do Wood Works

Welcome to Doobly-Do Wood Works!!!

By   24 Nov 2012

Welcome, and thank you for visiting our website!

After such a long time bringing the Wood Works into the digital age, we are finally…FINALLY proud to present to you our website, as humble and meager as it is.  This has been a herculean effort for our business, which tends towards the ‘Old School’ way of doing things.  However, our master woodsmith, The Grand Doobly, prides himself on trying new things with an open mind, and so we begin.

Keep checking back regularly to see what new and exciting products we will be offering.  At present, we only have our two Project Services (Design Services and CBTO Services) advertised on the website, as we are still learning how to organize our Ready-To-Ship (RTS) products on our website and mechanize / operate the shopping cart, payment and shipping modules, etc.  The weeks ahead promise to be filled with hard work and lots of learning, as we fill our pages with all the wonderful wood creations we make and ship nationwide.

Coordinated with our website launch, we have also become more social… specifically, you can now follow us on Twitter, Facebook and LinkedIn.  Links are in the lower right of the page.

Again, we can’t tell you how happy we are to see you here.

Mike @ Doobly-Do Wood Works