The Myth of Sole Flatness

I’ve never understood the obsession some people have over sole flatness. Somewhere along the way, a lot of folks got the impression that enough of the millions of vintage planes out in the wild are warped or distorted enough to warrant suspicion when buying. Worse, some even insist that for a vintage plane to be viable for use, it’s sole must be flattened.

Lie Nielsen states that their modern manufacture plane soles are ‘ground flat and square to .0015″ or better, regardless of length.’ Veritas planes have similar tolerances. Don’t get me wrong, I have nothing against either of these two companies. Heck, I own products from both of them. Certainly, if you’re spending $325 for a LN No. 5 Jack Plane made in 2020, you expect it to be dead flat. But is this a reasonable expectation in a plane that was made in 1920, and more important, is it even necessary?

In my opinion, sole flatness is a myth driven by modern day influences and perspective. We’ve been conditioned to believe that a couple hundredths or thousandths of an inch will somehow make or break the functional viability of the tool. But it’s silly to apply expectations of tolerances we get from computer driven milling equipment to mass produced hand tools made +/- 100 years ago. This is misguided at best, and completely unnecessary.

I suspect those who obsess over sole flatness fundamentally misunderstand how hand tools were originally used and likely have some pretty big misconceptions about 18th and 19th century furniture construction and finish. Hand planes were never intended to be precision instruments, at least not in the same way we think about precision instruments today. In today’s world, we tend to rely almost solely on the tolerance of our tools to produce precise results. 100 years ago, that was simply not the case.

Craftsmen and journeymen of the 18th, 19th, and early 20th century mastered the tools they had available and learned to compensate for any imperfections and limitations. Sure, some of them produced very precise pieces of furniture and cabinetry, but it was due to their skill and mastery, not the precision of their tools. And to be honest, most of the handmade furniture made during that period was anything but precise. Look closely inside and behind and underneath period pieces. The beauty and craftsmanship doesn’t lie in precision as we think of precision today. On the contrary, it lies in the subtle imperfections that reflect the hands of the maker and mark of his tools. That, in my opinion, is what makes it beautiful.

I’ve owned and restored many hundreds of vintage hand planes over the years dating from the 1870s to the 1980s. Some were in near mint condition, while others were closer to landfill fodder. Most fell somewhere in between, but the point is I’ve never seen one that was warped or cupped significantly enough that its usability was affected. All of them needed some degree of tuning and refining, but none required flattening. In fact, the only two planes I’ve ever “flattened” were two of my own block planes, and that wasn’t so much because they weren’t already flat, but because I wanted completely clean metal.

I’m frequently asked what kind of camera and lighting I use for my photos. I always respond that the secret to good photos doesn’t lie in better equipment or tools, but in mastering the equipment you have, learning to leverage its capabilities and overcome its limitations. Creativity isn’t stifled by constraint. On the contrary, constraints fuel creativity, innovation, and invention.

I think the same holds true for most other pursuits, as well. It’s certainly true for woodworking. Could I take even better photographs with a newer camera and broader selection of lenses? Sure. But that’s not the point. That’s not what makes me a better photographer, just as flatter plane soles won’t make me a better woodworker.


About Bryant
Bryant is a business management and organizational development executive with over 20 years’ experience focused on financial and operational efficiencies, talent development and optimization, improved employee engagement, and cultural alignment of teams within the organization. He has diverse experience in successful financial and strategic planning, brand management, leadership analysis and talent development, as well as designing and executing improvements to teams’ cultural efficacy and organizational alignment. Bryant has experience in both International Public S&P 500 Corporate and Non-Profit Sectors, and also runs his own entrepreneurial business venture, a consulting company specializing in helping small businesses and organizations improve operational efficiency, leadership development, and employee engagement . Bryant holds a Masters in Business Administration (MBA) and a Bachelors in Fine Arts (BFA).

6 Responses to The Myth of Sole Flatness

  1. Mark Nickel says:

    Flatness is an obsession of people who make shavings, not beautiful things out of wood. You hit the point when you said that the skill of the master far outweighs the “perfection” of the tool.

    Liked by 1 person

  2. billlattpa says:

    Agreed. A plane sole doesn’t need to be anywhere near perfectly flat for the plane to function. As long as the area directly in front of the mouth, and maybe most importantly, directly behind it are not protruding, a plane will work fine.
    Even a warped plane will work, just not all that great.


  3. John Sayles says:

    I too, have rehabilitated* literally hundreds of bench and block planes in my decades of woodworking. I have used or at least tried out nearly all of them, before either keeping or selling them on.

    I encountered exactly three planes in that time which need “flattening.”
    But let me be clear — all three were smoothers; a plane which needs to be able to take a thin shaving.

    All three had some variation of concavity around the mouth region. I “lapped” each on a flat substrate using wet-or-dry sandpaper.

    Once they worked well, I stopped. So even in these cases, the sole was not, at any time, dead flat across width and breadth.

    *”RESTORATION” is a widely misused term – 99% of all the plane “restorations” I’ve seen use black spray paint. An even greater crime is slathering the wonder compound BLO onto perfectly fine rosewood, thereby completely obscuring the grain.
    Japanning and lacquer would be the correct choices if one was at least attempting to “restore” the tool to the way it was originally made.


  4. Lew says:

    Any 3 points in a straight line form a PLANE. The toe mouth and heal. There now that’s as flat as you ever need. After all you just made a PLANE


  5. DirtyBrad says:

    Three points in a straight line form a LINE


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