The present demand for hard-wood finish for the interior of dwellings in what might be called cabinet-work style, is tending to displace the ordinary house joiners, and to put in their places men who heretofore have been simply cabinet makers. The style of finish in vogue necessitates the employment of workmen of the greatest skill. Ordinary carpenters, or even joiners of moderate skill, stand very poor chances of turning out satisfactory work where every joint must be invisible, and where neither paint nor putty is allowable.
This demand for house finishing has taken many men from the regular cabinet-making shops into those shops which also engage in house work. At present the pay is better upon house finishing than upon regular shop work, while the additional advantage of being more certain of steady employment in those shops which conduct both branches of the business than in those which carry on but one, takes many men away from the latter. (more…)
It is often hastily assumed by employers that artisans wearing glasses are not so well fitted to do certain classes of delicate work as those who depend exclusively upon their natural eyesight. This notion, it would appear, is a mistaken one, and in a recent work on the subject, Mr. R. B. Carter mentions one very remarkable proof of the harmlessness of using glasses—and even of employing a single glass.
Among watchmakers it is an unavoidable necessity of their calling to work by the aid of a single glass, and they appear to enjoy an enviable immunity from eye diseases. It is, he says, exceedingly uncommon to see a working watchmaker among the patients of the opthalmic department of a hospital, and he entertains little doubt that the habitual exercise of the eye upon fine work tends to the development and preservation of its powers.
The persons who suffer most, according to Mr. Carter, from popular prejudice and ignorance on the subject of spectacles, are men of the superior artisan class, who are not engaged on work which requires good eyesight, and who, at the age of 50 or sooner, find their power of accomplishing such work diminishing.
It is, he tells us, a rule in many workshops that spectacles are altogether prohibited, “the masters ignorantly supposing them to be evidences of bad sight, whereas the truth is they are not the evidences of bad sight at all, but only of the occurrence of a natural and inevitable change, the effects of which they entirely obviate, leaving the sight as good for all ordinary purposes as it ever was.”
Mr. Carter adds that “in many shops in which they are not prohibited they are still made an excuse for a diminution of wages; and the result of these practices is that hundreds of good workmen struggle on, perhaps for years, doing their work imperfectly, when a pair of spectacles would instantly enable them to do it as well as at any former period. In the present state of knowledge there is no excuse for rejecting a man’s services, or for diminishing his payment, because he requires spectacles, unless it can be shown that, even when he is furnished with them, his sight is below the natural standard of acuteness.”
Persons who are condemned to the use of spectacles will thank Mr. Carter for thus coming forward as their champion.
Carpentry and Building – August 1880
Quotations from:
Eyesight, Good and Bad: A Treatise on the Exercise and Preservation of Vision
Robert Brudenell Carter – 1880
The painting is John Cuff and his assistant (1772) by Johann Zoffany, commissioned by George III. John Cuff (1708-72) was a Fleet Street optician, maker of spectacles and microscopes.
Flitch-cut cherry log, showing end-grain splits (the boards are 2″ thick)
I recently returned from a week and a half in Colombia. While there, I got to experience some of the temperature and humidity extremes that we subject our furniture to: We traveled from the warm, humid llanos at Villavicencio, to the cool, wet cloud forests near Bogotá and in the Santa Marta range, to the hot, near-desert thorn forests of La Guajira. Fortunately, I personally contain very little cross-grain construction, so I emerged without any significant structural damage, save for a few mosquito and chigger bites.
Water exists in wood in two forms: Free water is water that occupies the voids in the wood, and generally behaves like a liquid. Bound water is water contained within the solid structure of the wood itself, and behaves more like a vapor “dissolved” in the wood. For our purposes, free water isn’t very interesting, as it moves freely (duh) via capillary action, and doesn’t contribute significantly to moisture-related wood movement. There is, however, some evidence that movement of free water is hindered when the surface of a piece of wood is very dry, which may be another contributor to the why-won’t-my-thick-slab-dry? phenomenon. As Chris noted previously, thick slabs often act as if the dry surface wood somehow seals in the moisture in the bulk of the wood, and it may be the case that free water is being trapped.
Bound water moves via diffusion. Imagine a large room containing 500 drunken woodworkers (e.g., the banquet hall at Woodworking in America). They’re all in there, randomly staggering around. We draw an imaginary line through the middle of the room, and discover that there are 450 woodworkers on one side of the line, and only 50 on the other side. Why? Guess which side of the room contains the open bar?
When the bar closes, the distribution begins to even out. This doesn’t happen because the woodworkers are purposefully trying to move away from the bar; it’s just that anything moving around randomly is more likely to move from an area of high density to an area of low density than the other way around, simply because there’s more “stuff” in the high-density area.
If the room has open doors, then some of the woodworkers will occasionally exit and end up in the hallway. As long as there aren’t very many woodworkers out there already, there will be more woodworkers exiting than coming back in. Eventually, a point will be reached where there are as many woodworkers randomly coming back in as randomly leaving, and the system will be in equilibrium. This is diffusion in a nutshell.
In a future installment, we’ll get into the nuts and bolts of diffusion, but for now we’ll skip all that and look at some wood, namely three boards, each 8′ long and 20″ wide, and 1″, 2″ and 4″ thick, respectively:
Imagine that you’re a molecule of bound water, located smack dab in the center of a board. Your quickest escape is through the face of the board, as the edges and ends are too far away. If you’re in the 4″ board, you have to travel four times as far (2″) to get out than you would if you were in the 1″ board. Remember from last time that the drying rate in this case goes as the square of the board’s thickness, meaning that it’s going to take you 16 times as long to go four times as far.
Now imagine that you’re a molecule of bound water very close to the end of a board. Your quickest escape is through that end. As we go from the 1″ board to the 2″ board to the 4″ board, your local environment doesn’t change; you’re still very close to the end of the board. In other words, the rate at which you leave the board is independent of the board’s thickness. And this is what gives dry kiln operators nightmares (and why many of them won’t touch thick slabs): The disparity between drying rates at the center and ends of a board increases dramatically as the board gets thicker, and along with that disparity comes increased stress in the board. The rapidly drying ends shrink faster than the center, with end splits being the inevitable result, as in the photo above.
This also applies to the faces and edges of the board, but as we will see next time, it’s usually less of an issue there, except for certain species, such as oaks, that have a strong tendency to develop surface checks, especially on tangential (flat grain) faces.
Even though some of the boards in the photo aren’t cracked at the ends, they nevertheless contain a substantial amount of built-in stress, leading to an increased likelihood of cracking after the board is placed into service. Knowing how the board’s neighbors behaved, and depending on how it will be used, I might inset a butterfly key on the underside of such a board to help restrain it. If I’m really nervous about it, I might even cut the board in half lengthwise, plane the cut edges and then glue it back together, just to be on the safe side.
We can reduce the drying rate disparity by covering the ends of the board with a substance that retards diffusion. (Again, slowing moisture loss from the end grain is usually more important than slowing loss from face or edge grain.) People have used a lot of different materials for this. In my own experience, latex paint offers some protection, but seems to be more or less worthless in the long term. I currently use a commercial water-based wax emulsion product, Anchorseal from UC Coatings, with good results. The absolute best product for eliminating moisture loss that I’ve tried is Leak Stopper aerosol roof sealant, but it’s a bit messy and kind of on the expensive side. I’ve also heard that oil-based aluminum paint works well, but I haven’t tried it.
Next time: The scary-looking diffusion equation! (You may want to ask small children and sensitive adults to leave the room before reading.) Also, we’ll answer the question of whether or not it makes sense to drill holes in a thick slab to hasten drying.
I have worked at coopering in all its different branches off and on for about thirty years; have seen it in its prosperity and felt its adversity. I have known the cooper who worked journey work to have a kit of tools weighing 100 to 150 pounds, and many curious-shaped tools they were, among which the only machine in use was a boring machine. Twenty staves from the rough were called a set and made a load to carry into the shop— rough heading four or six pieces—often causing the cooper to go back and make a second load to get a complete set for a barrel.
Old-time coopers will remember how a new man was broken into the traces; then, when his staves were equalized, shaved and jointed by hand, and heading made into a head, all of which required a mechanic to do the work, and our journeyman had his first barrel raised, there would go up from every cooper about the place a yell, “blockwash, blockwash!” that, only for the difference in the way it was done and the word itself, you would think there was fire in the next yard. The new cooper understood the rules, and if he hadn’t the money he got the boss to help him out, and the nearest saloon got the benefit of his first earnings by furnishing the ingredient (blockwash). (more…)
We know of no reason whatever that should prevent a good joiner from working hardwood as skillfully and as speedily as a trained cabinetmaker. As a rule, a good joiner can make superior cabinet work—Work that will stand more wear and tear than that usually turned out by furniture men; but the trouble lies in the fact that good joiners are very scarce.
The cabinetmaker must possess a certain amount of skill in the use of tools and finishing, or he will prove very unprofitable to his employer, a state of things not permissible nowadays; this skill may not be much; but much or little, it must be there.
On the other hand, there is certain rough work that can be done, about a building by any one having brains enough to dig a post-hole, and the rougher the work and coarser the operative, the more profitable to the employer.
Again, the wages paid the more skillful joiner is so little above the amount paid the coarser workman that it is scarcely worth striving for, more particularly so, when we take into consideration the fact that the higher the class of work the more expensive are the tools required to do it. (more…)
