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Dating of Old Houses
Henry C. Mercer, SC.D., Doylestown, Pennsylvania, 1923.


Mercer Museum
Construction Dating Information, especially Hardware, Center for Historic Preservation, Middle Tennessee State University
Nail Chronologies for Historical Archaeologists, David Moyer, RPA,
Iowa Office of the State Archaeologist


Wrought Nails Cut Nails After 1800Hammer-Headed Cut NailsStamp-Headed NailsWrought-Iron Door Hinges Cast-IRon Door HingesQuirked, Ovolo Door PanelsMachine-Made Door PanelsDoor Latches with Straight LiftsThe Norfolk LatchBlake's Cast-Iron Thumb LatchPointless Wood ScrewsSawed Laths Conclusions

The following observations are based upon notes taken upon the recent examination of about one hundred and twenty old houses in Bucks county and Philadelphia, Pennsylvania, built in the eighteenth and early nineteenth centuries, and it seems probable that the conclusions apply not only to old dwellings in Pennsylvania, but also to those in New York, New England, and the Southern states, where the same builders' material, carpenters' methods, tools and hardware were used during the period in question. The conclusions are as follows: that old houses may be dated within reasonable limits by the nails used; the hinges; the door panels; the wrought-iron thumb-latches; the Norfolk latches; the cast-iron thumb-latches; the wood-screws; and the sawed laths.

Wrought Nails

Handmade (wrought) nails of soft malleable iron, with rectangular shanks, drawn by hammer blows to a point and with clearly hammer-marked heads, were from time immemorial, universally used in house building, until about 1800 (in Philadelphia, 1797) when cut nails, because of their much greater cheapness, everywhere immediately superseded them. Therefore, where the original nails of a house are wrought, the house dates before about 1800; or, where cut, vice versa, after that date. All the evidence examined establishes this fact, with the following exceptions; namely, that long after 1800, wrought nails, to stand the jar, and because they would clench, continued to be used in the facings of window shutters; in the battens of doors; in the overlap of boards (old style) in lathed room partitions: or on door latches, etc., until about 1850. But these exceptions are not typical of the nails used to build houses after 1800. Nails used at the time a house was built are nearly always to be found in the garret floors. The wrought nail, no matter what its size, as generally used in house construction, is easily distinguished from the machine-made nails, called cut nails, above re-furred to, and described later. It was made from rectangular strips of malleable iron, several feet long, and about a quarter of an inch thick, called nail rods, which were furnished to the black-smith or nailer, who, holding one of them in one hand, heated its end in his forge, and then, on the anvil, pointed it with the hammer on all four sides. Next, he partly cut it, above the point, on the "hardy," with a hammer blow, and then, inserting the hot point into the swage hole, of his so-called ²'heading tool,' he broke off the rod and hammered the projecting end so as to spread it around the top of the hole; after which, the cooling, shrunken nail was easily knocked out of the orifice. Wrought nails, as free-hand forged products, vary greatly in style and shape, but the evidence examined has not as yet furnished any definite elate for any of their variations.

Cut Nails After 1800 

The far more easily made cut nail, as the evidence clearly shows, consists of a rectangular, tapering shank of iron, not hammered into a point by hand, but tapered, by a single cut, across a plate of iron. The smith was here furnished, not with a nail rod, but with a strip of plate iron, several feet long, about two and a quarter inches wide, and often about one-eighth of an inch thick. This strip he slid into a cutter, worked at first by hand power, resembling those used by bookbinders to trim books, and not here shown. This cutter, rising and falling rapidly, clipped off the end of the iron plate crosswise into narrow, tapering, rectangular slices or nails, whose length was established by the width, and thickness, by the depth of the nail plate. The taper of the cut alone, produced the point, but not the head. This was made at first by dropping the freshly cut piece, point downward, into a slotted clamp or vise, and then spreading the larger projecting end with a hammer, as in the case of the wrought nail. Cut nails are easily distinguishable from wrought nails by the following very apparent differences. Both have rectangular shanks, but the wrought nail tapers on all four sides; the cut nail, on only two opposing sides; the latter nail being as thick (namely the thickness of the nail plate from which it was cut) at the point as at the head. Moreover, the two cut sides of the cut nail show very plainly, minute parallel striations, always absent on the wrought nail, marking the down smear of the cutter. The evidence conclusively shows that these cut nails every-where superseded the ancient wrought nail at the end of the eighteenth century, namely, not long after 1797, when two cut-nail factories had been established in Philadelphia, and there-fore, if used by the builder, they will date a house as having been built after that year.

Hammer-Headed Nails c. 1800 to c. 1825.

A still further examination of cut nails, from dated houses, shows that they may be distinguished into two classes; namely those appearing between c. 1800 and c. 1825, with imperfect or irregular heads, or, more particularly, hammered heads; that is, heads showing the facets of more than one hammer blow, and those appearing after c. 1825, and throughout the following century, with stamped heads, showing level tops impressed by a single blow or stamp. Information gathered with difficulty from the Patent Office records and books, makes it probable (subject to correction by dated nails) that in general, up to 1825, the nail-cutting machines had not been perfected; in other words, that while after 1825, nail machinery produced cut nails at a single operation, before that time, two machines, run by hand power, but not yet by steam, nor even by water, one to cut, as described above, and another, probably nothing more than a special vise to hold the shank while hand-hammering the head, were used in the manufacture of cut nails. The hand-cranked machine, for cutting and heading nails at one operation, patented by Nathan Read of Salem, Mass., in 1798 (See model at Essex Institute, Salem, Mass.), was not a success. Neither were any of the other ²cutting and heading" machines, or simple ²heading" machines, in existence or patented at that time, as is shown by the evidence of the nails themselves, and further in the Diary of Rev. William Bentley, who visited Read's nail works in 1810 (See Essex Institute Historical Col-lections, April, 1918, page 113), and found that the workmen were then heading nails in the only way thus far successful, namely, by hand, "as it is found heading is done better by hand than by any machine as yet invented both as to time and good-ness of execution. Joseph Whitaker (See his manuscript diary in the library of the Bucks County Historical Society) was also thus making cut nails in Philadelphia, from 1809 to 1816-20, by a double operation; namely, cutting the plates with a hand-cranked ma-chine and afterwards hammer-heading the shanks held in a clamp worked by a foot lever. It further appears, that, at first, since the knife of the cutting machine was set diagonally so as to cross-cut the nail-plate into a tapered slice, the workmen had to turn the plate upside down at each stroke, so as to continue the taper by reversing the cut; and the very earliest cut nails (1800 to c. 1810) prove this fact by the down smear of the knife, round-edged above and sharp below, being reversed on the two opposing cut sides of the nail shank. They also show, that very early in the nineteenth century, this troublesome turning of the nail-plate was superseded by wriggling or staggering the blade of the cutter during the operation, so as to reverse the taper at each stroke without, turning the nail-plate. At first, also, in order to dispense with the difficulty of the usual heading, angle-headed (L headed) and headless nails called "brads" were made. But as these latter continued in use for certain purposes (often for floors) until long after the middle of the nineteenth century, their confused evidence should here be thrown out of consideration.

Stamp-Headed Nails After c.1825

An examination, not only of the records above mentioned but also of dated nails, shows that about the year 1825, the cut-nail machine, still working by water-power rather than by hand, and not yet by steam, had been so perfected as to make cut nails no longer by two operations but by a single operation in one ma-chine, in which the apparatus cut the nail, instantly clamped it and, at a single blow, stamped the head. These stamped heads, at first (c. 1825 to 1830) comparatively thin, lopsided and imperfect, became more thick, square and typically regular after 1830 and are always easily recognizable after about 1840. But regardless of their variations, in any case, stamp-headed cut nails, if used in constructing a house, reasonably date it as after about 1825.

Wrought-Iron Door Hinges

The evidence clearly shows that in the Colonial period in America the common iron, house-door hinges were made always of wrought iron until 1776 to 1783, when cast-iron hinges suddenly and universally took their place. The old wrought hinges appear in two common varieties in the houses examined; namely, the so-called H or HL hinge, cut out of heavy sheet iron and fastened against the face of the door with screws or clenched wrought nails, or the ²strap" or ²hook and eyeÓ hinge; namely, a long strap, bolted, riveted or nailed with clenched nails, against the door and turning on a hook or gudgeon which latter was either spiked into the lintel, or, where the lintel was too thin for spiking, set upon a plate, variously shaped, and sometimes strengthened with a projection or prop called a ²rattail." While the H and HL hinges (many of which were probably factory-made and imported from England) and nearly all of the strap-hinges, were found plain, a few of the latter, by no means typical and generally over-exhibited in museums, show floriated decorations. It further appears that hand-made, wrought-strap hinges (still common in 1923 on barn doors in eastern Pennsylvania and elsewhere), continued to be used on outer house doors and window shutters, long after 1783, and hence, when so found, should be disregarded as proof of dates, But with these exceptions, the evidence abundantly shows, that where wrought hinges (generally HL, more rarely strap) are found on original inner house doors, they date the house as Colonial, or built before the Revolution.

Cast-Iron Door Hinges

Cast-iron door hinges, called butt hinges, comparatively small, compact, book-shaped, mortised into the edges, not set upon the faces of the door, of the common present type (See Fig. 8), be-cause of their superior cheapness, came into universal use, no less suddenly, though a little earlier, than cut nails. They were invented in England by Izon & Whitehurst, and patented by British patent No. 1102, October 3, 1775, and were at first imported. After the interruption of British trade and house building by the Revolutionary War, they everywhere superseded the old wrought hinges, about 1784, after which they appear with- out significant exception, on all the dated houses examined by the writer. Hinges of this shape and name, i. e. butt hinges, of wrought-iron or brass, and never of cast-iron, bad been made before 1775, generally for closets, or furniture, but none was found by the writer on room doors, in the houses examined. Cast-iron butt hinges also show differences and improvements in construction (not studied closely) after about 1800. But regardless of these variations and allowing for the above noted survival of wrought strap hinges on outer doors and shutters, these cast butt hinges, found upon the original doors of houses, will date the latter as post Colonial or built after c. 1776-1783. This examination of old houses has shown no more remark-able and unlooked-for fact than that the door panels, before c. 1776, if edged as usual with mouldings, always show a plain. i.e. unbeaded ovolo or quarter-round molding on their outer margin, while immediately following the Revolution, after 1783, these same ovolo mouldings become scored with one or two quirks or beadings, or change into the ogee. It seems probable that this observation will apply not only to door and shutter panels, but also to wall and furniture panels. Nevertheless, lacking sufficient information, as yet, we here limit it to doors where it is significant enough. More probably caused by some technical change or improvement in journey, not yet explained, than by mere fashion, this sudden, marked and universal change in door panels seems all the more surprising, since beaded or quirked ovolo and ogee mouldings appear elsewhere in the woodwork of old houses, as, for instance, in cornices and the framework of mantels. Further, since old carpentersØ books describe hand-planes used to produce the latter mouldings considerably before 1776, it would seem reasonable to expect to find some exceptions to this rule; but the evidence of the houses in question shows none in the region examined, so that, subject to future correction, the information thus far gathered shows that hand-made door panels with plain ovolo frame work, if part of the original construction, will at once date a house as Colonial, or as built before c. 1776.

Quirked-Ovolo Door Panels, from c. 1776 to c. 1835.

As above stated, the evidence gathered shows that after c. 1776, door or shutter panels, in which the outer frame consists of an ovolo moulding with one or two beads or quirks (See Fig. 10), or an ogee, suddenly and universally supersede the old plain ovolo moulding, described as previously used, and continue in use on doors and shutters until machine-made mouldings take their place about 1835 (See Fig. 11). In all the old houses examined, no significant exceptions to this rule, or extended survivals of old, plain ovolo panels, during the period in question, have been found, so that thus far, the evidence abundantly shows that the more ornate (i.e. beaded or quirked ovolo) door panels described, if part of the original construction of a house, will date it as built between c. 1776 and c, 1835.

Machine-Made Door Panels After c.1835

Besides the two significant changes in door panels, above noted, a third change, later but no less marked, took place in their construction upon the general introduction of wood-working machinery, wood-planing mills, etc., about 1835. Revolutionary machines, of immense importance, to plane boards, make mouldings and otherwise work wood, had been in-vented in England by General Bentham, just before 1800 (See Knight's American Mechanical Dictionary) and no doubt were introduced into the United States and used about Boston, New York, Philadelphia, etc., between 1790 and 1835. Hence, very early machine-made door panels may be found later, in these and other old American cities, to prove the fact. But, in any case, these woodworking machines would have been run very restrictedly by water-power and not by steam, and the evidence shows that they were not established or their products used in the Pennsylvania country until after the general introduction of steam-power which gave birth to the modern factory about 1835. Before that time, in the houses examined, all mouldings on door panels, whether of the plain or quirked ovolo or ogee type, above described, were hand-made and appear as solid parts of the panel, planed by hand-moulding planes upon its framework; while after that time they were machine-made and nailed on, as loose strips, around the sunken outer marginal recess of each panel. It is not necessary for this purpose to consider the various sizes and shapes of these machine-made mouldings, nor to reason from the fact that they were introduced, not suddenly, but gradually, that the old styles of hand-made panels continued in use for a good while after their introduction. To discover that loose strips of moulding have been nailed on around the sunken outer marginal recess of a panel is sufficient: that fact, where they are part of the original house construction, establishes the date of the house as not earlier than about 1835.

Door Latches with Straigh Lifts, Before 1800

Besides other door fastenings, namely box knob locks, wooden latches, brass latches, German lever latches, boxed or unboxed, knob latches, etc. not here described, many original doors in old houses still standing, show their original wrought-iron thumb-latches, made of malleable iron by blacksmiths in five hammered pieces, i.e. the hand grasp, an lever with thumb press at one end penetrating the door to raise the bar; the bar thus lifted; the staple holding the bar against the door face; and the catch, a "figure 4" shaped, notched, iron piece, spiked into the lintel of the door, into which the bar falls. These old latches are sometimes decorated, but commonly plain, sometimes home-made and sometimes probably imported. Some-times they show their thumb-lifts fixed on swivels (the swivel-lift latch); sometimes the thumb-lifts are notched into holes (the perforated cusp latch), and sometimes their latch-bars appear with, but generally without, a knob or curl or pinch grasp. As yet no fixed types have been found to which dates may be ascribed beyond the following; namely, that the inner end of the lift, opposite the thumb-piece, commonly though not always appears straight before about 1800; after which it more and more often shows the familiar down curve under the bar, characteristic of modern cast-iron latches. Doors latched with these straight-lift latches, some of which are very short, are sometimes hard to open, and sometimes, as if to remedy the difficulty, knobs or pulls appear on the bars of latches of early Colonial date. But these early knobbed-bars are rare and it seems all the more remarkable that the very helpful down-curve above mentioned should not have been more generally used be-for 1800; nevertheless curved latch-lifts have been heard of by me, and seen by Mr. Frank K. Swain, in old houses in England, and in Pennsylvania, dating from the earlier period in question, e.g., several at the Community House, Bethlehem, Pa., built about 1742, and several at the Letitia Penn House, Philadelphia, c. 1682 (doubtful). Since the writing and first publication of this paper in Old Time New England, The Bulletin of the Society for the Preservation of New England Antiquities, for April, 1924, Mr. Albert H, Sonn has seen a curved lift-latch on a library door at Hadham, Conn., traced to an old mill built about 1740; one on a house at West Stockbridge, Mass., and one at Newfane, Vt., besides finding more recently a dozen or more in various parts of the eastern United States. Dr. A. Bertram Gilliland has also found several with scrolled, upturned lifts in the Stebbins House at Deerfield. Mass., built in 1772; one from the Pastor Williams House, Deerfield, built in 1770, and one at Washington's Head-quarters, Newburg, N. Y., built before 1800. If more should appear later, the present evidence shows that they will continue to occur 'as exceptions, and that in general a down turned latch-lift, if part of the original construction, will date a house after 1800.

The Norfolk Latch, After 1800

The very conspicuous Norfolk latch, is easily distinguished from the wrought thumb-latches, in having its hand-grasp not enlarged at each end into plates, or cusps, but riveted upon a long, narrow, sheetiron escutcheon. Though long known in England as hand-wrought by local blacksmiths, it nevertheless appears in the American houses examined, as a factory-made and not smith-wrought product probably at first imported from England. Gradually taking the place about 1820 of the other forms of thumb-latch and competing with the knob-latch and the German lever latch, it rivals, for a while, the newly invented earthen door-knob with cast-iron box, until it is generally superseded by the latter and by Blake's patent cast-iron thumb-latch of 1840. The evidence shows that these factory-made Norfolk latches were constructed sometimes with, and sometimes without, a knob on the bar; sometimes, at first, with a straight lift and sometimes, later, with a curved lift, sometimes, at first with a spiked catch and sometimes, later with a catch perforating or riveted upon a plate. But without attempting to infer too much from these variations, we may at least conclude, from the evidence, that the factory-made Norfolk latch, if contemporaneous with the building, will date a house between 1800 and 1840, or, allowing for survivals, 1850.

Blake's Cast-Iron Thumb Latch, After1840

Numerous dated examples found, show that Blake's typical cast-iron thumb-latch, with circular catch-plate mortised and screwed into the door lintel, hollow patent bar-pivot, hollow staple guard, and saucer lift with opposite down-curve, patented by United States patent No. 1704, July 21, 1840, first came into general use on and after that year. It seems probable that this latch was preceded by rare cast-iron experiments or improvements, i.e. cast-iron grasps on older wrought latches of the Fig. 12 type, etc., and was closely followed by evasive copies or patent infringements. But Blake's latch was, and still is, (1923) the cast-iron latch par excellence, and without concerning ourselves with earlier un-patented predecessors or variations of it or copies or patent infringements of its very typical catch or staple, this latch, when complete and original, as the evidence clearly shows, will date a house built after 1840.

Pointless Wood Screws Before 1846

The unmistakable pointed wood screw, now universally used, was patented by United States patent No. 4704, August 20, 1846, before which time, all wood screws in general use, unless pointed by hand-filing, were blunt. Because these pointless screws would not start by driving into the wood, penetrate, except by a previous gimlet or brad-aw hole, the pointed wood-screw suddenly and universally superseded them. Therefore, the wood-screw if pointless and original, will date a house before 1846; if pointed, after that date. These facts, marking the end of the old house-building period, though only applicable to the very latest buildings, are nevertheless important, since they may help to detect wholesale restorations or additions and show when kitchen fire-place doors stopped open-fire cooking, or where old latches, hinges, or doors have been shifted out of time or place.

Sawed Laths, After c. 1825 to 1835

Sawed laths, i.e. thin strips of machine-sawed wood, about three feet long, by two inches wide, by a quarter of an inch thick, as keys for interior wall furring and partition plastering, first appear about 1825 to 1835. Though sawed, they were not produced by the water-run, vertical-frame saw of the old saw mills, but were first made by circular saws, abou t1825 to 1835, on the general introduction of the circular saw, before which time, riven laths, i.e. hand-split with a frow and mallet, were invariably used, and no such thing as a sawed lath existod. Riven laths were occasionally made and used for some time after the introduction of sawed laths, and therefore will not date a house as built before 1825, while sawed laths will, if original, date it as built after that time.


In conclusion, it should be said in general, that in collecting and attempting tc estimate the above facts, it soon became certain that very few of the old houses examined had escaped alterations and repairs and therefore, unless the details above noted could be proved in each case to be part of the original construction, their evidence only led to error and confusion. With this reservation, reasonable certainty was always sought for and often found. Very few houses appeared to have been raised or broadened. Therefore their original garret floors remained intact and the conclusive evidence of nails used therein, was easiest reached. When rarely, because of new floors, or L headed cut nails. this failed, we generally found it on staircases, in wash-boards or else-where in the house, and when, at times, this evidence seemed contradictory, some Further fact, family tradition or historical record, showed that old doors or hinges, screws, or latches, had been inserted out of date into new houses, or vice versa. Doors appeared original if set in original partitions; if frequently duplicated; if not cut down on their margins: and if with their hinges not covering old mortise nail or screw holes or outlines of removed hinges. Door panels; if on original doors; if frequently repeated or matching shutter panels. Latches; if often duplicated, and not betrayed as resettings by the marks of nail, screw or lift holes, etc., or of other door fastenings. Pointed or pointless wood screws; by their general use or appearance with otherwise original wood or iron work; and sawed laths; by their original use in partitions or in original furrings over rough unplastered walls. Out of at least one hundred and fifty houses examined, about fifty were found dated by documentary evidence, or by date-plates or wall-stones; and (he evidence of nails, woodwork and hardware, first studied in these dated buildings, always repeated and never contradicted itself in the undated houses examined later. As far as this evidence goes, it is very positive; but as yet, though quite definite after the Revolution, it fails to fix any subdivisions of time for the Colonial period (1650 to 1776).