Excerpted from The Chronicle Vol. 31 no. 1, March 1978
by Warren E. Roberts
A close examination of any wood screws used is of great importance in attempting to discover the date at which a wooden artifact was made. The artifact in question may be a house. a piece of furniture, a tool. or anything else of wood. If one can remove wood screws from it and has reason to believe they were used when the artifact was originally made, the screws may provide valuable evidence as to the date of construction.
Henry G. Mercer, that remarkable scholar whose wide-ranging interests made him an authority in many fields. dealt frequently with wooden artifacts made in the eighteenth and nineteenth centuries. His early interest in prehistoric archaeology led him to apply some of the approaches of the archaeologist to artifacts from the much more recent past. Consequently, he realized the importance of the wood screw for dating purposes. He showed that early wood screws were laboriously made by hand and that they tapered to a point. By the early 1800s, however, screws were being made in large numbers by “a continuous-motion mandrel lathe, axled on a guide screw. This lathe. therefore, advancing as it revolved and clasping at one encl the screw shank, threaded the shank by twisting it through a knife-edged hole, or, more exactly, between two steel cutting points compressible by a lever.” Mercer continues, “Nevertheless, the screw so produced was conspicuously deficient in a very important feature. namely. that it lacked a point. In other words, those nineteenth century screws, so much more rapidly machine-made, though often somewhat tapered in the shank, unless retouched by hand, were invariably blunt-ended, and would not, before 1840, penetrate wood without a previously bored or punched hole. Then, by United States Patent no. 4704. August 20, 1846, T. J. Sloan of New York, patented a machine to point them, after which, because when thus pointed, they would more easily grasp the wood and would screw into it after a hammer tap, they so universally superseded the pointless screw, that their sudden and novel presence, as part of its construction, would very closely date a house as built after 1846.” (1)
To summarize then. it may be said that a screw may be elated with fair precision as follows: if it is pointed but uneven in shape, it is from before about 1800: if it is blunt-ended. it is from between 1800-1846: if it is pointed but even in shape, it is from after 1846. It should de noted that Mercer used this type of evidence in dating carpenter’s tools. In describing a spokeshave, for instance, he says, “In No. 9053, made after 1846, as proved by its pointed wood screws …” In describing a level, he says, “Pointed wood screws used in its construction date it after 1846.” (2)
Finding the date of construction of old houses presents many problems. In my experience, it is rare to find reliable written records. The records maintained at county courthouses in Indiana, at least, deal only with land and not with the buildings on the land. In the absence of written records, a close examination of the fabric of a house is about the only way to arrive at an approximate elate of construction. If written records are available, it is still important to scrutinize the fabric of a house as a supplement to or a check on the records. Many of the pieces of evidence found in a house give only rather general indications as to date. For example, if we find the marks left by a water-powered ”up-and-down” sawmill on the undersides of floorboards or on floor joists, about all we can say is that the house was built before steam-powered circular saws came into use in the area. For southern Indiana that would mean before about 1875.
We can usually ascertain whether or not the hardware used in a house is original. While the hinges. door latches. and the like may have been changed in the front part of a house where visitors are usually entertained. it is generally possible to find original hardware on closet doors, cellar doors, and other more hidden spots. While the hardware itself may give reliable elating information, in my experience it is the wood screws that hold the hardware in place that are most frequently useful.
In my efforts to elate old houses in southern Indiana, I have often relied on the evidence from wood screws, for the period between the time of first settlement around 1820 and the Civil War is often important. As far as I know, no one has challenged Mercer’s dictum that the machine-made point wood screw suddenly superseded the machine-made blunt wood screw in 1846. Recently, however, in investigating two old houses, I have found screws in each house that I am convinced are part of the original fabric, some of which are pointed while some are blunt. In such a situation, it is clear at once that the house in question cannot be older than 1846. The puzzling question, though, is how long after 1846 were blunt screws in general use?
Among a small number of woodworking tools that I have collected is a heavy rosewood spirit level and plumb. The screws in the brass encl plates are number 8, 3/4 of an inch long, and are blunt ended: those in the brass top plate are number 4, 1/4 inch long, and are pointed. On the brass top plate is a touchmark of an eagle with a shield and the makers’ names: Lambert, Mulliken and Stackpole. Boston. Mass.(3) My experience with the houses, each of which had both blunt and pointed screws, motivated me to try to determine when this level was made. A survey of Boston city directories, which were available to me on microfiche, showed that the company is first listed in 1852 as “manufacturers of plumbs and Levels” at 6 Haverhill (4), while in 1856 the company name is listed as “Mulliken and Stackpole.” Since the company may have been founded in 1851 and not listed in the directory until 1852, we can say that the level must have been made between 1851 and 1856.
In this case, it is clear that blunt screws were being used some years after 1846. What is needed is more evidence to aid in the elating of a wide range of artifacts made of wood. It would seem that tool collectors are in a very favorable position to compile this useful evidence. There is obvious difficulty in locating and visiting large numbers of houses whose elates of construction are reliably ascertained, and the same would hold true for accurately dated pieces of furniture. In the hands of tool collectors, however, there must be a reasonably large number of examples of tools that can be dated with fair accuracy on the basis of patent dates, dates carved by the owner or maker, or by other means. Collectors would not only assist their fellow collectors but also would aid research in other fields if they would share the information they have or could acquire in this connection. I would propose that those who have information or who can obtain it by removing and examining screws from the tools in their collections send it to the editor of The Chronicle so it can be published and made generally available. It might then be possible to amass firm data or corroborative data on the following questions:
(1) When were machine-made blunt ended screws first used? Mercer was unable to supply a firm date, using only the phrase ”towards the end of the 18th century.”
(2) When were machine-made pointed screws first used? Even though a patent was grantee\ in 1846 for a machine to make them, it may have been some time before they were produced in any quantity. Moreover, there may be a difference between British and American manufacturers, and many tools used in the United States in the first half of the nineteenth century were made in England.
(3) How long were machine-made blunt-ended screws used after 1846? It is, of course, possible that stocks of blunt-ended screws on hand were used up even though pointed screws had become available.
(4) Were screws in smaller sizes made with points before the larger sizes of screws were made? The evidence I have would indicate that they were, but much more evidence is needed.
While on the subject, I may venture to request information on another matter concerning wood screws that may also help in dating artifacts. Most of the old screwdrivers I have seen have tips that taper like a wedge, no matter whether the screwdriver is large or small. Modern screwdrivers, on the other hand, have a blunter end and parallel sides for a short distance from the end. My first impression was that the old screwdrivers had been reground carelessly, but as I saw more of them it became apparent that there was too much consistency in this respect to be the result of accident. The slots in the heads of blunt-ended screws I have been able to examine also seem to taper, being wider at the top than at the bottom. Unfortunately, I own only a few tools from the first half of the nineteenth century and the heads of the screws in these tools are mostly so rusty as to make it impossible to tell about the slots. Moreover, while I have been able to remove a number of screws from old houses, the heads have usually been either very rusty or covered with layers of paint. More evidence from examples of screws in good condition would be useful in this connection; dated screwdrivers with wedge-shaped tips would likewise give valuable evidence. It would seem that if there was a change in the shape of the slot in screw heads, the makers of screwdrivers would have to likewise change the shape of the tips of their screwdrivers. A wedge-shaped screwdriver tip in a screw slot with parallel sides does not work at all well. Information on this question would help date screwdrivers, screws, and artifacts with screws in them.
It is entirely conceivable that there are written records available that would throw light on the questions raised in this paper. There may be catalogs, manufacturing records, advertisements, inventories, and the like that show with great accuracy when the change from blunt screws to pointed screws occurred. For example, if such written records can he found, information should likewise he published, but it still would be valuable to have corroborative evidence from specific datable tools.
Since writing the above, I have acquired a plane that can serve as an illustration of the importance of knowing when pointed screws superseded blunt screws. The plane is an iron plow plane with a wooden handle. It is designed to take cutters of different widths and is basically a metallic version of the common wooden-handled plow plane. I acquired only the main stock of the plane; the arm, the fence, and the cutters are all missing. The cutter in the stock is made from a broken chisel.
The only marking on the stock is the word “PATENT” cast in the metal in large letters. A search through patent records failed to unearth any information. The plane’s wooden handle, however, is fastened to the metal stock with two blunt wood screws. The screws would seem to indicate a date of manufacture not much later than 1850.
In a brief article entitled ”Patent Plow and Combination Planes, 1850-1900,” John Juby implies that the first iron plow plane was patented in 1867. He cites an example patented in that year and calls it a ”solid first step in the evolution.” (6) The question at once arises, is it safe to assume that the plane described above is earlier than 1867 on the basis of the screws used in it? If we had a substantial amount of data from well documented sources, it would be possible to answer this question.
- Henry C. Mercer, “Ancient Carpenter’s Tools”, 3rd ed. (Doylestown, Pennsylvania: The Bucks County Historical Society, 1960), p. 256. Essentially the same information is given in Mercer’s The Dating of Old Houses (Doylestown, Pennsylvania: Bucks County Historical Society, 1923). pp. 21-25.
- “Ancient Carpenter’s Tools” p. 104, Figure 98 and p. 66, Figure 64.
- The level is 25-1/2 inches long by 3-3/8 inches by 1-3/8 inches The top plate is 8-3/16 inches long with semi-circular indentations at each encl. The side plates forming the “brass lipped side views” as they are called in older catalogs, are rectangular. The small plates over the hole in which the plumb glass is inserted are round and of brass. The end plates of brass are so constructed that they wrap around the body of the level and are help in place by two screws at the lop and two at the bottom.
- The Boston Directory for 1852. (Boston, George Adams, No. 91 Washington St., 1852.)
- “Ancient Carpenter’s Tools” p. 256.
- Iron Horse Antiques, Inc, 1976. Catalog Number 12, p. 7. Juby includes a photograph of another example of the plane described but is unable to give any information as to the date of manufacture or patent.