the Carpentry Way: Computer Numeric Re-Considerations (II)                                                          

Computer Numeric Re-Considerations (II)

The topic of CNC (Computer Numeric Control)-operated woodworking equipment has been on my mind a lot in recent days. I have had many discussions with my wife, with the woodworkers upstairs in the building where my shop is located, with the jewelry shop people in that same building, and in the exchange I have had with one of the commenters following up from the first post in this series. I was surprised there weren't more comments, more people up in arms. it seems like a contentious topic to me at least.

One of the comments raised a point, and it is one leveled frequently at CNC-produced objects: the 'coldness' which arises from their 'perfection'. In relation to CNC-produced bicycle components, the commenter (my friend in Nagano, furniture maker Dennis Young) mentioned:

"What is gained in precision and lightness, is lost in warmth",


"No two are exactly the same, more individuality in that, less sterility."

Fair comment, and I do agree that such is often the outcome with a lot of machine-produced items. But I don't think CNC-produced items are especially unique in this regard, nor do I think it is necessarily the case that CNC-produced items can only be inherently cold or sterile. Are Karl Holtey's planes, which feature much CNC-work, sterile?

I'd like to explore that idea of uniformity/sterility/warmth in terms of workmanship a little further today, and I want to be clear that I am not trying to persuade so much here as share the thoughts and ideas that have been current in my consideration of this topic. I find it an intriguing area to explore, and in which to question my own assumptions and prejudices, having never used CNC machinery and been critical of it in the past.

Here's a point that occurred to me in regards to the hand-wrought product: as a craftsman, my objective in making things is in fact to obtain as much precision as I can. I don't imagine too many joiners, come to think of it, working with an intention to create sloppily-fit joints. Some may perhaps be inattentive, or satisfied with mediocrity, but they do not seek to produce poor work, unless they are mad, say, at their boss.

My interest and drive in my process of working wood and creating things is that I want joints to fit with just the right amount of pressure and with good alignment. I want the hand-planed or scraped surface to come out dead flat with no tool marks left behind. I want the molded bead on one side of the table apron to be the same shape and size as the bead on the other aprons. And you know, I never seem to quite achieve those objectives, though I do strive hard to do so, and will continue to strive in that direction. It might be an impossible task to achieve such perfection. It seems to me that if I did achieve that degree of perfection in my product, there would be some observers who might therefore think that product 'cold' or who would think it must be a machine-made product.... It's a little perverse. Welcome to the modern world.

Some craftspeople go to the trouble of making their work look deliberately imperfect so that it looks more 'hand-made', leaving behind -or adding - tool marks, or making things look like they are joined together traditionally when in fact they are not, using materials which look more overtly like the tree they came from (with waney edges, knots, inclusions, rusty bolt holes in salvaged material, etc.. A case in point are Greene and Greene chairs, sideboards, etc., where the pegs often cover screws or are simply decorative, and interior trusses are often simply decorative interior accessories, grand as they do look.

And, as many woodworkers know, the term 'hand-made' is a bit nebulous/subjective to begin with - not that it needs to be, only that it has become so it would seem. On the recent table project, I indeed used such classic hand tools as chisels, planes, scrapers, marking gauges, and hand saws. But I also used powered planers, jointers, routers, drill presses, and so forth. Is that table therefore hand-made? Not strictly speaking. Is it machine made? Not exactly, or at least, not entirely. It's somewhere in the middle. I suspect that vast numbers of woodworkers, at least those making furniture, arrive at their results in much the same way as I did, albeit with less hand tool involvement, and more machine work, being more typical of the process I would say.

I don't, in fact, want to do all the work by hand. Hands up, those out there who would choose to hand plane 1/4" of material off a 12" wide curly bubinga plank to get it down to a thinner dimension? That task would take at least a full day of fairly strenuous labour I would suspect. And if there were a stack of boards upon which the same work need be performed? The novelty might wear off of planing it all down I suspect. Give it a try and see.

Or, hands up again, would you rather run the plank through the planer and get the work done accurately in a few minutes? Or, who would have opted to rip the 20" wide table top panels for that Ming table with a hand saw off of the 3" thick piece of stock? I suspect few takers, and even if there were one or two, I am going to guess that they aren't professionals in the woodworking arena. Nothing wrong with being an amateur, but time constraints are less of a worry in that form of the endeavor obviously.

I might add that it is not always the case that hand tool work is slower - it can often be faster in certain aspects. But not usually when there are large numbers of parts to be processed identically at one time, which is a large portion of the process of making - then the machine is much more efficient.

So, the vast majority of us, we 'hewers of wood', are using machinery to one extent or another. Indeed, based upon what I have seen, I would say 99% of woodworkers utilize powered machinery for virtually all of the work they do. I rarely come across woodworkers with sharp hand tools, for instance, though their business card might depict a jack plane or handsaw. These hand tools are becoming decorative, I dare say, in many shops

All that said, for many, the hand touches, few as they may be, are often the points of pride in the making of the piece. In the western tradition, for instance, there is a tremendous emphasis on hand-cut dovetailed drawers, as one example. Let me digress slightly if I may....

The dovetailed carcase as such is approaching a form of fetish in fact, an obsession among woodworkers - a detail which might be scarcely noticed by the clients who buy the pieces. I think most woodworkers are aware of that point.

It was interesting to note what happened when machines to cut dovetails appeared on the scene in the early 1920's or thereabouts. While the bulk of hand-cut carcase dovetailing was done fairly quickly - and not always all that tidily - in most production settings, the machinery allowed for even faster production of these joints, and got greater uniformity and, I would say in some cases, more predictable quality in production. It can be said that in many cases the machine-made stuff was a form of cheapening a product, and little else.

Those who didn't like the new technology decried the sterility and uniformity of the machine-made dovetail. They still do. And then they chose an interesting course of action in their handwork in relation to dovetails: to focus on making dovetails with ultra-narrow pins, even 'zero-point' dovetails. This now became the hallmark of craftsmanship. Why? Because the spaces on the 'tails board' for such pins could not be cut with a machine!

It's a little whacky though, when the joint is considered from a mechanical integrity perspective. While narrowing out the pins could allow for dovetails to be crowded more tightly together, which would mean greater surface area and a stronger joint, in practice, from what I have observed, the pins get spaced in much the same way as they would with thicker pins. And so, in the quest to lay claim to some apparently hallowed ground in which the machines can't gain entry, the product now makes use of pins which are so skinny as to be weaker than is ideal. Or so it would seem to me.

Further, the dovetailed carcase joints while it is a mechanical connection in one direction at least, without glue it would come apart. So, since glue is really what keeps it together, and since, as many have asserted, modern glues are so wonderful, finger joints would be just as fine a connection. Dovetailed drawer ends are more visually dramatic and are a point of show-off for the maker in a sense. But if you consider the highest class of woodwork, the full through dovetail is somewhat down the list of preferability- considered superior were half-blind dovetails, then full-blind dovetails, and, in the best work, the ultimate method was considered to be concealed mitered dovetails, which are "true craftsmanship without ostentation", as I have read of them being described. Do that though, and many might think you had used dowels or biscuits to put it together. So, since it is not something that can be easily shown, most woodworkers would not opt to make such joints. In short, the reason for the dovetails is largely for show, to communicate a meaning, to make a statement. If they weren't so obvious to view when a drawer was opened, I'm willing to wager that you wouldn't see them done so often.

And the other point in regards to all this fuss about the dovetails which scarcely bears mentioning but I will do so anyhow, is that the consumer, while they may understand to an extent, or have at least been told that 'dovetails' are a sign of quality construction (and, as an aside I would add that no buyer in Japan looking at a high class tansu would be giving any thought to dovetailed drawer construction), if you were to show that consumer a drawer with dovetails that had been produced by one of the better jigs on the market, and a drawer with dovetails made by hand, they would not likely be able to spot the difference. And even if the craftperson pointed out, beaming with pride, the skinny pins in the hand cut dovetails, and told the client what they signified, I expect that at best you would get from that client a shrug, or a slightly hesitant and uncomprehending nod and murmur of 'oh, I see', when in fact they are perhaps thinking 'what is the nut going on about?'

So, these skinny dovetails are often, I dare say, something done to impress other woodworkers, to make a show (that only another woodworker would likely notice) of a part being hand made - - when the rest of the piece may well have been cut almost entirely with power tools. It's a funny thing. It may not always be a show for others - it may be something the woodworker does to simply validate to themselves what they are doing as a maker, to tell themselves that they are still, uh, hewing that material the old fashioned way, at least in some small part. And I'm not saying there is anything wrong with that, per se, only to show the lengths some makers will go to claim some of that precious 'hand-made' cachet in their work.

The zenith of quality handwork, from a 19th century perspective at least, is the perfect surface, the crisp carving, the light-tight joinery. And if you achieved it in a piece, people would likely think, in this day and age, that it was machine made. This puts the craftsperson in a position of having to have some portion of their work clearly look hand-done if they want to signify clearly that the piece is hand-made.

So, given that inhuman, 'cold' perfection is associated to the machine, many will associate some slight irregularity in a piece with the work of the hand - the errant tool mark here and there, the scraper mark left behind, the one leg that is subtly shaped differently than the others, the carved flower with detail differences from the other ones nearby, etc.. This is the sort of imperfection and diversity that delighted Ruskin. And here's the shocking thing: there's no reason you can't have the exact same outcome with CNC, if that is the desired result. I find that somewhat humorous actually.

It is no issue to program the CNC such that each piece, say one cabriole leg, is varied from the next in some slight way. This is not what happens in practice, from what I've seen, however it is very much within the realm of the machine's capabilities. Or, as is already done in some non-CNC work, one could go over the CNC'd 'perfection' and deliberately place tool marks. Yes, it's not what might be called honest craftsmanship, and it's not something I would be interested in doing, but as an approach it would be nothing new in the world of furniture making.

So, I've given some attention to the idea that CNC-produced work need be inherently sterile. I don't think it is necessarily the case, at least in terms of the capabilities of the technology. I might add that certainly there is no shortage of conventionally produced woodwork that is sterile, lacking in variation, craftsmanship, or visual interest. Even hand carving can be insipid or magnificent, depending upon talent of the carver.

In the following posts on this topic - and I've got a fair amount to say yet - I'll delve into other facets of this intriguing CNC question.

Thanks for coming by the Carpentry Way today. Comments always welcome. --> on to post III

Labels: ,