Dover Manufacturing Co. No. 4 Asbestos Sad Iron
SSC MUSEUM COLLECTION
Catalog No. SSC-DOVERMFG-SAD-4-001
Asbestos Sad Iron | Detachable Hood & Handle | No. 4 Size | Canal Dover, Ohio
c. 1900–1920 • Dover Manufacturing Co. • Ohio Foundry Corridor
Profile view showing the classic sad iron silhouette: the smooth, pointed soleplate tapering to a pressing tip at front, with the nickel-plated hood and wooden handle assembly seated on top. The spring-loaded latch mechanism—patented May 22, 1900 by Ole Tverdahl (U.S. Patent No. 649,968)—locks the hood to the heated core and releases with a thumb lever, allowing the user to swap handles between multiple cores heating on the stove.
Every woman in America ironed clothes. In 1900, that meant heating a heavy chunk of cast iron on a wood-burning stove, gripping it with a handle that grew dangerously hot within minutes, and pressing fabric until the iron cooled too much to be effective—then repeating the process with a fresh iron while the first one reheated. It was exhausting, time-consuming, and punishing on the hands. The Dover Manufacturing Company of Canal Dover, Ohio, built its entire business on solving one part of that problem: the hot handle.
The solution was asbestos. A layer of asbestos insulation was built into a removable hood that sat over the heated iron core, creating a barrier between the heat source and the wooden handle above it. The handle stayed cool—fifteen degrees below blood temperature, the company claimed—while the soleplate stayed hot. The design used interchangeable parts: a housewife could buy a set of cores in different sizes and shapes and swap a single hood-and-handle assembly between them, always using a hot iron and never burning her hands. It was an elegant engineering solution to a universal domestic problem, and it made Dover Manufacturing one of the most successful specialized foundries in early twentieth-century Ohio.
This No. 4 size sad iron is a complete unit: the cast iron core with its smooth soleplate, the nickel-plated hood with its asbestos lining, and the wooden handle with its spring-loaded latch. It carries the patent date May 22, 1900—the date of U.S. Patent No. 649,968, granted to Ole Tverdahl for the improved locking mechanism that allowed the hood to be quickly attached and detached from the core. It is marked “Dover Mfg. Co.” and “Dover Canal Ohio”—the company’s early marking, referencing the town’s original name of Canal Dover before it was shortened to simply Dover in 1915.
The Asbestos Sad Iron Design
Top view showing the wooden handle grip mounted on the nickel-plated hood via two rivets. The spring-loaded latch lever extends from the rear of the hood. The cast knob at the handle’s rear end provides a thumb rest for operating the latch. Inside the hood, an asbestos lining and air gap separated the handle from the heated core below—the key innovation that kept the user’s hand cool during ironing.
The word “sad” in sad iron has nothing to do with emotion. It derives from an Old English word meaning “solid” or “heavy”—and heaviness was the point. A sad iron worked by pressing wrinkled fabric smooth under the combined force of heat and weight. The heavier the iron, the less effort the user needed to apply. A No. 4 size was a small-to-medium iron, lighter than the full-sized No. 6 or No. 9 models, suited for lighter fabrics, collars, cuffs, and detailed pressing work. In a typical household, a set of asbestos sad irons would include two or three cores in different sizes—the No. 4 for fine work, the No. 6 for general pressing, and possibly a specialty shape like a flounce iron or fluter—all sharing the same detachable hood and handle.
The three-part design—core, hood, and handle—was the heart of the Dover system. The core was a solid cast iron body with a smooth, ground soleplate on the bottom and a raised lip or shelf around the top edge. The hood was a nickel-plated shell that fit over the core like a cap, with an asbestos lining on its underside creating an insulating air pocket. The wooden handle was riveted to the top of the hood. A spring-loaded latch at the rear locked the hood onto the core; pressing the thumb lever released it, allowing the user to lift the hood-and-handle off one core and drop it onto another that had been heating on the stove. The whole exchange took seconds. The user always had a hot iron and a cool handle.
Bottom view showing the smooth, ground soleplate of the cast iron core. The pointed pressing tip at front allowed the user to work into pleats, seams, and tight areas. The soleplate surface is smooth with surface wear consistent with use and age. The hood-and-handle assembly is visible seated on the core at the rear.
Piece Details
Manufacturer
Dover Manufacturing Co.
Piece Type
Asbestos Sad Iron (pressing iron)
Form
Cast iron core with nickel-plated asbestos-lined hood and detachable wooden handle; spring-loaded latch mechanism
Size
No. 4
Material
Cast iron (core), nickel-plated iron (hood), asbestos (hood lining), wood (handle)
Marking
“Dover Mfg. Co.” / “Dover Canal Ohio” / “Patent May 22, 1900”
Patent
U.S. Patent No. 649,968, issued May 22, 1900 to Ole Tverdahl — improved hood and core locking mechanism
Date of Manufacture
c. 1900–1920
Place of Manufacture
Canal Dover (now Dover), Tuscarawas County, Ohio
Condition
Good — hood, core, and handle assembly complete and intact; spring latch functional; wooden handle intact with age wear; nickel plating shows wear; soleplate smooth with surface patina; no cracks
Acquisition Date
March 7, 2026
Acquisition Source
eBay — Seller: radishrose
eBay Item Number
236661077807
Order Number
23-14314-48870
Purchase Price
$22.75 item + $10.50 shipping + $2.82 tax = $36.07 total
SSC Catalog Number
SSC-DOVERMFG-SAD-4-001
Collection Designation
Ohio Foundry Corridor
The Dover Manufacturing Co.: From Stoughton to Canal Dover
The Dover Manufacturing Company began its life five hundred miles from Ohio. In 1893, two men of Norwegian ancestry—Charles T. Johnson-Vea, an entrepreneur not yet thirty years old, and Ole Tverdahl, an inventor in his early forties—went into the sad iron manufacturing business in Stoughton, Wisconsin. Their company, Tverdahl-Johnson, started with a patent based on an idea from Tverdahl’s wife Mathilde. The product that would define the company came from another Stoughton resident: Dr. Lorenzo D. Clark, who gave Johnson-Vea his concept for a sad iron with an asbestos layer and air pocket between the handle and the hot pressing surface, along with a crude working model. Johnson-Vea and Tverdahl refined the design, produced an improved version, and brought it to market.
By 1898, Tverdahl-Johnson had more than forty employees. Johnson-Vea wanted to expand further—particularly to gain better access to markets in the eastern United States. In 1900, he moved the company five hundred miles east to Canal Dover, Ohio, secured additional capital investment, and reorganized the business as the Dover Manufacturing Company. Johnson-Vea became the company’s director. Canal Dover offered everything the expanding operation needed: proximity to eastern markets, access to the Ohio and Erie Canal transportation corridor, and a location in the Tuscarawas Valley’s established iron-working region. The Reeves family’s iron and steel mills had already made Canal Dover and the surrounding “Iron Valley” a center for metal manufacturing.
Dover Manufacturing described itself as the only “exclusive sadiron concern” in the world—a company in touch with “the housewife’s ironing problems.” Within a few years of the move to Ohio, it employed more than two hundred men and sold between three hundred thousand and five hundred thousand items annually. The asbestos sad iron became a nationally advertised product, sold through hardware stores and mail-order catalogs across the country. The company spent years and thousands of dollars securing its patents, with the critical Clark-Johnson patent coming through on May 22, 1900, and Tverdahl receiving additional patents for the locking mechanism in 1903 and subsequent years.
The asbestos sad iron’s commercial window was relatively brief. The product flourished in the first two decades of the twentieth century—the last generation before electric irons began to transform domestic laundry work. By about 1920, new asbestos sad irons were fading from the American market, though they continued to be exported internationally. The town of Canal Dover itself was renamed simply “Dover” in 1915, which is why earlier pieces like this one carry the “Dover Canal Ohio” or “Canal Dover” marking, while later production carries just “Dover, Ohio.”
Corporate Timeline: Dover Manufacturing Co.
1893
Charles T. Johnson-Vea and Ole Tverdahl establish the Tverdahl-Johnson Company in Stoughton, Wisconsin. Initial production based on a patent from Tverdahl’s wife Mathilde.
c. 1895–1898
Dr. Lorenzo D. Clark provides his concept for an asbestos-insulated sad iron. Johnson-Vea and Tverdahl refine the design and bring it to market. Workforce grows to over 40 employees.
1900
Johnson-Vea moves the company to Canal Dover, Tuscarawas County, Ohio. Reorganized as the Dover Manufacturing Company. U.S. Patent No. 649,968 issued to Ole Tverdahl on May 22, 1900 for the improved hood-and-core locking mechanism.
c. 1900–1910s
Dover Manufacturing grows to over 200 employees, selling 300,000–500,000 asbestos sad irons annually. Nationally advertised through hardware stores and catalogs. Described as the only “exclusive sadiron concern” in the world.
1903
Additional patents secured by Tverdahl for locking mechanism improvements.
1915
Canal Dover officially renamed “Dover.” Earlier products marked “Dover Canal Ohio” or “Canal Dover”; later products marked “Dover, Ohio.”
c. 1920
Electric irons begin displacing sad irons in the American market. New asbestos sad iron sales decline domestically, though exports continue.
Canal Dover and the Iron Valley
Canal Dover’s name tells its own history. The town was founded by Christian Deardorff along the route of the Ohio and Erie Canal, which was constructed between 1825 and 1832. By 1840, thanks almost entirely to the canal, Dover’s population had grown from just 46 people in 1820 to 598—larger than the county seat of New Philadelphia. The canal brought raw materials in and finished goods out, enabling the Tuscarawas Valley to develop into what locals called the “Iron Valley”: a corridor of iron and steel manufacturing anchored by the Reeves family’s steel mills and surrounded by dozens of smaller manufacturers and foundries.
The Dover Manufacturing Company fit naturally into this industrial ecosystem. When Johnson-Vea relocated from Wisconsin in 1900, he was choosing a town with an existing infrastructure for metalworking, a skilled labor force experienced in iron and steel production, and transportation connections to eastern markets. The Tuscarawas Valley offered coal for fuel, iron for castings, and railroad connections that the Ohio and Erie Canal had originally established. Dover Manufacturing joined a manufacturing tradition in Tuscarawas County that stretched from early blast furnaces through the Reeves iron and steel era and into the twentieth-century diversification that would eventually include plastics, chemicals, and other materials.
For the SSC collection, this piece represents the first entry from Tuscarawas County—a new county on the Ohio foundry map and a new pin on the SSC’s Ohio Foundry Directory. Dover is approximately seventy miles south of Cleveland and ninety miles east of Columbus, placing it in the eastern Ohio industrial corridor that connected the state’s coal and iron resources to its manufacturing centers. The Dover Manufacturing Company is exactly the kind of specialized, single-product Ohio foundry that the SSC collection is designed to document: a company that built its reputation on one product, served a national market from a small Ohio town, and left its name cast into iron that survives more than a century later.
Why This Piece Matters
The Dover Manufacturing Co. No. 4 asbestos sad iron matters because it represents the SSC collection’s first piece from Tuscarawas County and its first piece from the sad iron category by a dedicated pressing-iron manufacturer. Dover Manufacturing was not a general-purpose foundry that happened to make sad irons alongside skillets and kettles. This was a company that made nothing but sad irons—the self-described only “exclusive sadiron concern” in the world—and it made them in Canal Dover, Ohio, in a factory that employed over two hundred men at its peak. The “Dover Canal Ohio” marking dates this piece to the early production period, before the town dropped “Canal” from its name in 1915, making it an early example of what became one of the most widely distributed cast iron products in early twentieth-century America.
The piece also tells a broader story about Ohio’s foundry economy. Dover Manufacturing did not grow organically from a local tradition. It was transplanted from Wisconsin because Ohio offered something that Wisconsin could not: proximity to eastern markets, access to the Iron Valley’s manufacturing infrastructure, and a place in the industrial corridor that connected Ohio’s natural resources to the national economy. The company’s success—three hundred thousand to five hundred thousand units a year—was built on that Ohio advantage. And the product itself captures a moment in domestic technology: the last generation of non-electric pressing irons, engineered to the limits of what cast iron, asbestos, and mechanical design could achieve before electricity rendered the whole category obsolete.
The iron endures. The markings tell the truth. The story deserves to be told.
Sources & Further Reading
Smithsonian National Museum of American History — “Asbestos Family Cabinet” (Object NMAH 311817): Complete Dover Manufacturing Company asbestos sad iron set. Notes on company founding by Johnson-Vea and Tverdahl in Stoughton, WI (1893); move to Canal Dover, OH (1900); U.S. Patent No. 649,968 issued May 22, 1900.
HomethingsPast.com — “Asbestos Sad Irons – Cool Ironing Days”: Detailed business history of Tverdahl-Johnson Company and Dover Manufacturing Company, including Dr. Lorenzo D. Clark’s contribution, move to Canal Dover, employment figures, annual production volumes, and patent history.
Powerhouse Museum (Sydney, Australia) — Sad iron collection entry (Object 209120): Dover Manufacturing Company, Canal Dover, Ohio, c. 1900–1930s.
Dover Ohio: A History (blog) — “Canal Dover and the Current of History”: Ohio and Erie Canal development, town founding by Christian Deardorff, population growth, Reeves iron and steel mills, Great Flood of 1913, renaming from Canal Dover to Dover.
SSC Internal Collection Records.
About Steve’s Seasoned Classics
Steve’s Seasoned Classics is an online museum dedicated to preserving and documenting the heritage of American cast iron, with a focus on Ohio foundry pieces from the 19th and early 20th centuries. The SSC collection features over 130 pieces with detailed provenance, historical research, and photography for each item.
