Computer Numeric Re-Considerations

I’ve been in touch with an architect from Pittsburgh in the past couple of months who has invited me to collaborate on a residential project in urban Pittsburgh. The structure is to be 30′ x 60′, two main floors with smaller rooms under the roof, which is to be a Mansard. He wants me to design the Mansard, which is to have exposed timber framing, and there is also discussion that I will design a geometrical (helical) main staircase and some intriguing dormers. At this point it remains a discussion so we’ll see what happens.

You will note in the above paragraph that I said design, not design and build. The architect’s intent, at least with the timber roof portion of the project, is to have the timbers cut by another contractor, using lasers no less. While I remain a bit skeptical at this point, apparently it can be done with larger timbers now, so I’ll keep an open mind. The staircase work and the other double curvilinear work with the dormers seems to be intended for production via the world of 5-axis CNC.

So, I am left, in considering the opportunity, assessing the situation here – how do I feel about designing and not building? What is important to me about the process of making objects? Lots of questions have been swirling through my mind of late, and one of the things I have been thinking about is Computer Numeric Control, or CNC for short. I’m already very dedicated to drawing my pieces on the computer, and see many advantages to it, so the steps over to CNC are not so far. A lot to think about however!

My previous experiences looking at CNC-produced timber frame work has not been one of being awestruck. The surface qualities of the timbers I saw retained obvious machining marks, the fit of the joinery was not as good as I would have thought possible, and the product overall had a somewhat ‘cold’ feel – I know that is a bit of a nebulous description, but it’s the best word I could think of to describe it. That said, a tool is a tool, and while I do not believe in the so-called neutrality of technology, I remain open minded when it comes to the capabilities and directions made possible by new forms of technology. At one point, people resisted the introduction of the telephone, while today I hesitate about texting.

Technology can be used in various ways, and not all of those ways can ever be fully envisioned by the developer of a given technology – indeed, there are many examples of a technology being developed for one express purpose which then found wide use in some unexpected field later on.

So, with CNC, what is the purpose – why do companies adopt this technology? From my examination thus far, and from reading various testimonials from companies that have gone to CNC for some aspect of their production, the common reasons include:

  • obtaining consistent product quality run to run
  • improving product quality
  • improving interface between design and manufacture
  • increasing productivity

CNC finds wide application in production of large multiples of a given part, whether it be elliptical molding, stair-rail parts, plywood chairs, and so forth. CNC is also very useful in prototyping before production begins.

Now, it isn’t the mass-production/productivity equation that appeals so much to me. Like any other type of woodworking, if the design is ugly or poorly conceived, CNC adds only a reduction in price. Indeed, lots the CNC-produced stuff I have seen in wood is of little to no appeal to me.

However, that’s not the point. The capability of CNC is to produce really any design which can be envisioned, and fabricated, potentially, with high accuracy. That does appeal to me. Here’s a point – my interest in bicycles, for instance, involves CNC. My current ride has quite a few parts on it which are produced by CNC, including the headset and hubs, stem, seat post, and so forth. My life rides on those parts – they must be reliable. I like it if they are beautiful too! Actually, the fact that they are produced by CNC is an additional bonus, even a cachet to those products. Look at this handlebar stem for example, made by Italian firm Extralite:
Now, though it may look like a machined chunk of aluminum (which indeed it is!), what you are not seeing is the hundreds of hours of design work that went into this product, including finite element analysis. The stem is machined out to the wazoo and weighs less than 100 grams. I’ve had it on my bike for several years now with no problems.

Is it cheap? No. But consider what it would cost to have it made by hand. I don’t even know if
I’d want it made by hand – the product is pushed to a technical limit of materials, and frankly I think I would trust the CNC more. I certainly know that I could only afford the CNC-produced item.

Consider Karl Holtey, the esteemed British maker of metal-bodied woodworking planes. He’s now making a ‘transitional plane‘ (<– a link), which is wood-bodied with a metal Norris-style adjustment mechanism. The soles of his planes are made of two woods locked together by lots of oblique sliding dovetails:
The above joint is an example of a connection that couldn’t be well made any other way than CNC. Intriguingly, he doesn’t use his planes to process the surfacing cuts on the plane sole parts – he uses his CNC milling machine.

Take a look at a photo series (<– link) depicting the steps involved in making his #982 smoothing plane. Anyone out there who would say that these planes are not desirable due to the fact that computer numeric machining is involved? Does it look 'cookie cutter' to anyone out there? My point is that CNC can be used to produce extremely precise objects, and really the beauty is part of the designer’s skill. Most people, I think, would choose beautiful and precise over ugly and precise, however there are many who would also choose beautiful and poorly made over ugly and precisely made. Funny how that goes – and that’s why there are so many neat designer products that don’t last very long. Consumers usually are not oriented to the details of how something is made or care even about how long it will last. This is the consumer society and that is how the conditioning has been done.

I’ve got more to say on CNC – today’s post is the opening salvo about a topic to which I have devoted a fair amount of thought recently. –> on to part II

5 thoughts on “Computer Numeric Re-Considerations

  1. Thanks for posting that link. Those planes are like a piece of are you would hang on the wall instead of abuse on a workbench. I'm burning all of my planes and replacing everyone with one of his, I'm now taking donations!

  2. Precise and accurate, but to my eye as a cyclist with numerous bikes, both classic and more modern, your stem is no way as visually appealing, as say a Cinelli designed hand welded stem from the 50s and 60s. What is gained in precision and lightness, is lost in warmth, and in no longer revealing the benefits of someone having cared to accurately first do, then clean up and polish the welds, etc. A skilled job for them, a pretty result for yourself. No two are exactly the same, more individuality in that, less sterility. Bicycles were once art, sadly that has largely disappeared into feats of engineering. One of the potentials of cycling is gone, and for someone who knows a bit about the history of bike frames and components, not to some degree disallow the so called advantages of lightness calls for restraint.

    Costs aside, more and more people are loosing the sense from not seeing the attractiveness that something hand crafted, or possibly at least less technologically advanced made, often can give. There are examples of this everywhere. Often, the desire for advancement of “new” by the consumer is a corrupting idea, defeating visual advantages of former approaches, and it becomes a driving force via advertising that industry uses to produce great profit making results. In this regard, people continually are manipulated.

    I have seen CNC aided woodwork that seemed more practical for putting out a more artistic product, that which was done with hand skills applied after the computer did the initial work. Faster and faster shouldn't be the guiding impetus.

  3. Paul,

    I'm sure you're not alone in that aspiration!


    beauty is in the eye of the beholder, or so I have heard.

    You wrote,

    “Bicycles were once art, sadly that has largely disappeared into feats of engineering.”

    Perhaps you are unaware of the renaissance in hand-built bicycles? The North American Handmade Bicycle show is now into its 7th year -check it out:

    Lots to drool over on that site.


  4. Right, Chris, I am aware of a number of the contemporary frame builders, own a fairly new Tommasini, and I consider some of the work to be of the highest order, often a greater accomplishment in terms of workmanship and thoughtfulness of design, than many of the most sought after frames from earlier eras.

    My comments about the loss of 'atmosphere', so to speak, mainly were referring to the more high tech approaches, as evident in the vast majority of pages in today's cycling magazines. Also, you are correct, I am the beholder and the critic, a right and responsibility that I don't lightly give to myself. Although CNC made components, or state of the art molded carbon frames, for example, sometimes appear to me as sculptural to begin with, some nice shapes, the forms aren't something that hold my interest over an extended time, a criteria that I use to discern what is beauty for my own pleasure and study.

    Many of your woodworking photos also show a pair of digital calipers. I sense that exactitude is something that you find exciting, challenging, and appropriate for your own way of working. In that regard, it seems like the CNC process may carry a certain degree of attraction with yourself, given the right circumstances beyond which you have seen before. Part of the debate in your mind? I also appreciate 'spot on', but my guidance is more how I 'feel' it to be, looking at things by asking myself, less reliance on things peripheral. A hand planed table top known to be done well by feel, or seats shaped evenly from left to right with an adze and planes, because my eye tells me so, such are skills that can have wide application to a diversity of woodworking projects. Relying on CNC, might that in some ways prove debilitating, contrary to the pursuit of more basic useful skills? What point is your career at? I'm not suggesting anything, simply asking. Up until recent, one of the complaints against the people who were highly trained at using CNC metal lathes and milling machines, was that the vast majority of them had never learned to use the older types of pre-compurtized gear, so more unusual work or short runs were not much within the realm of a good productivity. That seems to have changed to some degree with the now increased user friendly and more sophisticated equipment.

    Saying that beauty is in the eye of the beholder kind of refutes all arguments, and possibly makes Yanagi Soetsu stir in his grave, who cared much less about the type of production, than what were the results of it. I completely agree with that, but I also think that some types of work methods are more conducive to reaching aesthetically pleasing results, whether you are talking about precision round washers for the space shuttle, or wooden furniture for people to use in their humble homes..

  5. Hi Dennis,

    thanks for your thoughtful comment. Yes, saying that “beauty is in the eye of the beholder” does tend to refute all arguments, however that wasn't my intent. I might have said, more usefully perhaps, 'different strokes for different folks” or, in Japanese 十人十色 (“ten people, ten colors”).

    About the digital calipers: I measure things with them. I also use rulers, tapes, and squares as many woodworkers do. It's not some much that I derive 'excitement' from the use of digital calipers, it's that I find them a very convenient way to measure, and, most definitely I do find hitting close tolerances rewarding in my work. It doesn't mean that their use replaces the feel of the joint going together, it just means that I can associate a given feel with a given dimensional tolerance. I like the added information and it does help in certain processes. Could I make joints without that tool? Of course! Some might prefer to squint at a ruler, interpolating between lines – I find glancing at a digital readout faster and easier. Also, they are robust tools that work well in a shop environment.

    Your comment, “Relying on CNC, might that in some ways prove debilitating, contrary to the pursuit of more basic useful skills?”, was intriguing. I know what you mean, but…

    What constitutes 'relying' exactly? Does it connote some sort of helplessness necessarily? I look around me and reflect upon the vast number of things I rely upon. Like this computer for instance, which I would not be able to make for myself. In the shop, I rely upon the sawyers and foresters to supply the material, the blacksmiths and tool makers for my equipment, and on and on it goes.

    And the pursuit of “more basic useful skills” – this is a value judgment. Some would have mourned the loss of skills in making suits of armor, which were 'basic skills' that became highly evolved and refined over time. Or the loss of penmanship with the advent of the typewriter and later the computer.

    I can use a handsaw, plane, and chisel, however I do not choose always to use those tools for certain tasks at certain times. Some woodworkers would have decried the invention of the handsaw at one point in history as the saw does not have to follow the grain of the wood, thus is associates to a loss of a certain type of understanding of material. I am not about to throw my saws, hand or powered, out of my shop anytime soon however.

    And if one already has a good command of “basic useful skills”, (which can always be refined further, ad infinitum), then what? Should one stay within the tools one knows how to use, and is comfortable using, or risk trying something new?

    As for Yanagi, I wonder about your assessment. After all, he does spend much time in extolling the virtues of the fact that the most esteemed tea ceremony bowl in Japan is a 15th century mass-produced Korean piece. It seems to me that the way the piece was made, in non-conscious reflexive perfection of movement, was a point about which he made considerable emphasis.

    As for, “What point is your career at?”

    Uh, that's never really crossed my mind and how would I know the answer to that? What do you think? Hopefully I'm not in the declining phase anyhow!

    I can see this topic is one which stirs you up, so I look forward to further discussion. One thing though – do you think that CNC cannot be used to produce aesthetically pleasing results?


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