Wood Hardness Ratings

The Janka hardwood rating test is a test that determines the hardness of a piece of wood (used mostly to determine the hardness of flooring planks).  Quite often the hardness of a piece of wood relates directly with its density.  Wood carvers, however, can use the Janka hardwood ratings to compare one type of carving wood to another.  For example, one can easily see that Basswood is near the very bottom of the ratings chart indicating that it is one of the softest of the hardwoods.  Black Walnut, on the other hand is much further up on the ratings chart and is considered to be much harder to carve than Basswood.  Below is an explanation of the Janka ratings test and a chart including some of the more popular North American hardwood species.

Janka Wood Hardness Ratings

When in doubt about the type of wood to select for your cabinetry, flooring, furniture or millwork project, refer to the Janka Rating System, which measures the relative hardness of woods. 

The hardest commercially available domestic hardwood is hickory; it is five times harder than aspen, one of the “soft” hardwoods. And while this example lists just some of the most popular hardwood species, there are hundreds of varieties, representing the North American hardwood population. 

Because hardness is an important factor, and hardness varies for each species, the Janka Scale of Hardness is an excellent tool to help identify appropriate choices.

So what does the Janka test consist of? The process of measuring the density of wood begins by embedding a steel ball that has a diameter of 11.28 millimeters (roughly 0.444 inches) halfway into the wood’s surface. The force required to push the ball into the wood (measured in pounds-force, or lbf) indicates how dense and strong the wood is. For example, hickory hardwood has a Janka rating of 1820; this means that it required 1,820 pounds of force to embed the steel ball into hickory’s surface.

The hardness and density of wood is often determined by the direction of its grain. Measuring a wood’s flat or horizontal grain (face) is the most general way to determine its hardness. Although vertical wood grain (edge) is tested, the results are not displayed on the Janka Hardness Scale. The results shown on the Janka Hardness Chart indicate the hardness of a wood’s face, and not its edges (or “side hardness”).

Common Domestic Species Janka Ratings

This should only be used as a general guide when comparing various species of wood flooring. Depending on where the wood is harvested the results may vary. Plank construction and finish are also important factors when determining the durability and ease of maintenance of any wood floor.

COMMENTS

After seeing the above Janka Hardwoods ratings chart I noticed something that sheds some light on a discussion we had a few days ago regarding Cottonwood.  Rick Boyer wrote in and asked since cottonwood bark is so widely carved does anyone ever carve cottonwood itself?  My response was that while I had never carved cottonwood (only cottonwood bark) I couldn’t say how it carved but did know it is considered to be a hardwood.

Upon looking at the Janka chart I see that cottonwood is very low on the hardness ratings (just above basswood).  It’s only 20 rating pounds higher than basswood so my guess is it probably carves very much like basswood.  Therefore, like basswood, cottonwood is considered to be among the softest of the hardwood species.  So Rick, if you can get a hold of some cottonwood I would definitely give it a try.

SUPPLIER LIST:

I want to put together a comprehensive list of wood carving suppliers who supply anything from tools, accessories, supplies, roughouts, safety equipment, books, etc.  Even wood!  While I have quite a large list of my own I want to hear from my readers on who they like to use.  This way I can add them all together and make up one large list.

So if you have some wood carving suppliers you would recommend send them in!  I’ll need their name, contact information (phone #, website), and basically what they supply.  Thanks!

Let the chips fly!  Tell your friends about Wood Chip Chatter, and don’t forget to send in your questions and comments so we can keep Wood Chip Chatter Active and keep the conversations going!

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to carverbobk@woodchipchatter.com

Keep a sharp edge and keep on carvin’!

My wife and I were watching Who Wants To Be A Millionaire while we were in bed.
I turned to her and said, ‘Do you want to have Sex?’
‘No,’ she answered.
I then said, ‘Is that your final answer?’

… She didn’t even look at me this time, simply saying, ‘Yes..’
So I said, “Then I’d like to phone a friend.”

And that’s when the fight started…