© Philadelphia Year Book, 1917.
Disston and Sons, Keystone Saw Works, 1872-
6700-6800 State Road & 5100-5200 Unruh Street, Philadelphia PA 19135
(between Unruh Street and Princeton Avenue, east of State Road to the Delaware River)
© Harry C. Silcox, Ed.D.,
Workshop of the World (Oliver Evans Press,
At its zenith, Henry Disston
and Sons employed an average of 2,500 workers, covered
sixty-four acres, and comprised sixty-four buildings.
Until its sale to H.K. Porter in 1955, it was a
family-run firm. It had sales branches in nine cities,
including Tokyo, and a plant in Canada. The largest saw
manufacturer in the world, Disston and Sons also produced
files, tools of all types, springs, and steel plate, as
well as special steel jobs. The company's Keystone
trademark on a product indicated high-quality to all who
knew the reputation of the firm. 1
Saws remained Disston's best known product throughout its existence; indeed every imaginable sort of blade for cutting wood or metal was produced at the saw works. The process of creating a handsaw blade involved eighty-two steps. It began with the making of steel in crucible pots which were poured into molds that produced ingots. The ingots originally were flattened by screw-type vices; later steam pressured hammers were used. The process of flattening continued in the rolling mills, where large sections of rolled steel plate were routinely turned into saw plate steel. After teeth were cut in the steel "in the soft," the metal was tempered in a precision furnace before hardening in a bath, it was then heated again in a tempering oven and allowed to cool naturally. Tempering gave the steel elasticity (spring) and durability. The next step was "smithing,"—hand-hammering the blade to perfect flatness and subjecting it to several stages of grinding and filing. The trademark then was etched on the blade and the teeth were set by angling every other tooth to the left or the right. Thus, when the saw was in use, the teeth cut a channel slightly larger than the width of the blade, which prevented the blade from binding in the channel.
Disston produced wooden saw handles and the brass screws with which they were attached to the blades. This process involved eighteen steps. Handles were made from applewood logs, which were first cut to the proper thickness and then aged in the open air for three years. The applewood was then "ripped" cut, marked to pattern, sawed inside and outside, oiled, nose-fonned, sanded, varnished, carved, polished, bored, and split. Finishing the handles was one of the few jobs that women performed in the Disston works, (the company employed 195 women and 2,605 men in 1916). 2
During its peak years ofproduction, Disston used some 35,000 files per year to sharpen saws. Thus, file-making machines and mechanical sharpening machines were important components of the Disston plant. Files, like saws, demanded the best hard steel available. The steel ingots for the files received a slightly different treatment in the rolling mills than those used to produce saws. The file ingots were reheated and rolled into large bars. These bars were cut into pieces, which in turn were rolled into bars of decreased diameter and increased length until they formed the size of file required. Once the desired thickness and widths were reached, the strip of steel traveled to the file works where it was cut into proper lengths. The file blank was then "tanged," the tang being the smooth, pointed end on a file which is usually fitted with a handle, although frequently it could be employed without a handle. This was done by heating one end of the file and forging a tang from it. The worker in this operation was seated before an automatic hammer with a small furnace close at hand. The temperature in the file oven was crucial to this operation, as too much heat would prevent the file from being properly teethed and too little heat would not allow the workman to successfully mold the tang.
The files were put into air-tight boxes and placed in annealing ovens, which were set to a predetermined temperature. Once removed from the oven, the files cooled in the boxes, not in the open air. These processes caused the file to warp, or become uneven, so that it then had to be taken to the straightening department, and thence to the grinding department where the files were made perfectly smooth so that teeth could be cut evenly into them. The teeth were then cut into the soft metal with a chisel-like machine, and a final heating hardened the file. In all, Disston produced 50 types of files, some flat, some rounded, and with variable teeth that ranged from the rasp file to a fine file for aluminum. 3
The Disston plant site is divided by Knorr Street into two main components. North of the Knorr Street gate on New State Road are the steel and power plants, and the rolling mills, to the south are the offices and production buildings. The steel plant consists of an armor-plate building, a steel-fumace building, and rolling mills. The armor-plate building had large dies that stamped out plates of steel for tanks in World War II. Making steel required raw iron and steel scraps which were stored in a large yard located next to the steel furnace building. The crucible pot method was used to melt the ore and scraps to form ingots. Adjacent to the steel-fumace building were the rolling mills, where the steel ingots were rolled into sheets of steel. The stack on the power plant, which dominated the Tacony landscape for years, was destroyed by an explosion in 1951 when workmen did not properly blow out the gas fumes from the stack before igniting the furnace. Except for the rolling mills and the annor-plate building, these structures are empty shells today.
The area south of Knorr Street is far more complicated to describe, it contains a jumble of varied buildings, some dating back to the 1872-1878 era. These include grindstone sheds, a hardening shop, lumber yard, file forge building, jobbing building, machine building, and production buildings for hand saws, long saws, circular saws and band saws. With the exception of the lumber yard and the grindstone sheds most of these buildings are still standing today.
A small part of the site south of Knorr Street remains industrially active under ownership of Disston R.A.F. Industries. This company produces large circular saws for cutting hot steel. A small hardening shop, a torch-steel cutting shop, and a teeth-cutting and smithing shop function daily. More than twenty employees work under the direction of Roland Woehr. However, this factory at New State Road south of the Knorr Street gate is a shell of the once mighty Disston and Sons Keystone Saw Works. 4
1 Harry C. Silcox, "Henry Disston and Sons 1840-1955: The Rise and Fall of America's mightiest Saw Works," unpublished manuscript, (Philadelphia, 1989).
2 Philip Scranton and Walter Licht, Work Sights, Industrial Philadelphia, 1890-1950 , (Philadelphia, 1986), pp. 170-181.
3 "The File, Its History and Making," The Disston Crucible: A Magazine for the Millman, (January, February, March, April, 1914), [available at the Free Library of Philadelphia, Logan Square, Philadelphia].
4 Interview with Bob Bachman and Roland Woehr at Disston and Sons site by Harry C. Silcox, December 27, 1988.
Update May 2007 (by Torben Jenk):
Many buildings remain, but most are in poor shape.
The buildings along the north side of Unruh Street include decorative cast iron "star bolts" (describing their common shape)which are here shaped like keystones with the letter 'D' within, a clear reference to Disston and the Keystone Saw Works. Stacks of grinding stones are visible where Unruh Street meets the Delaware River, some stuck together with concrete and formerly used as a bulkhead. Truck and auto repairs seem to be the only use today. It appears that the buildings directly north of those along Unruh have been demolished. Farther up State Road, at #6795, is the entrance road to Disston Precision and the rest of the former Disston complex. The wall along State Road to the north is made of sandstone, possibly from used grinding stones. On the south side you get the best idea of the campus of two-story brick buildings. To the left are 20th century buildings, tall single-story metal structures, mostly vacant. Farther east along the Delaware River is a finer collection of used grinding stones.
Most impressive is the steel furnace building with a date stone that reads, '1940.' Only forty feet of the chimney remains beside this robust building. Ovalized iron flues pierce the roof-like glassless skylights, while the interior is gutted and rotting.
Farther west is the rolling mill, identified by a date stone that reads '1936', and shows a keystone and a roller in relief. An auto scrap yard occupies the space to the north.
Disston Precision is still in operation and makes huge saw blades, valve components, press plate, clutch components, shredder knives and slitters. Disston offers the following services: heat treating, flattening, grinding, laser cutting, plasma burning, waterjet cutting, precision machining and fabrication.
Other tenants include Marjam, which distributes building materials; and American Lighting and Signalization, which installs and maintains roadway lighting, traffic signalization, airport lighting, street lighting, interstate signing, and underground and overhead utility lines.
There is talk of adapting the Disston complex for loft apartments, and commercial and office space. Most of the other industrial sites along the Delaware have or will be demolished. The complex at Disston offers an opportunity and challenge for a creative developer who wants to offer something more enticing than the two-thousand vinyl-clad, vanilla box townhouses being proposed just north and south.
To the north of Disston, on the south side of Princeton Street, was the Tacony Army Plating Plant, built in 1941 with the mission of making plates for tanks in WWII. The 200,000-square-foot building remained open through the 1970s and officially closed in 1983. At a cost of $10 million, the US Army Corps of Engineers demolished the building in 2004. The site was sold at auction for $2.5 million and plans exist for 407 residences to be known as "Tacony Pointe." A small park is along the Delaware River with a public access Tacony Boat Launch. Just north of Princeton Street, along the Delaware, is the Quaker City Yacht Club, a private club for boating enthusiasts and social members, established in 1887. It leases land from the adjacent and still operating St. Vincent's Orphan Asylum, which is shown on the 1895 Bromley Atlas (plate 48). The same plate shows the “American Wire Glass Mfg. Co. of Frank Shuman.
Harry C. Silcox, "A Place To Live and Work, The Henry Disston Saw Works and the Tacony Community of Philadelphia" (Pennsylvania State University Press, University Park, PA, 1994).
Hexamer General Survey #707-708 (1873) "Henry Disston & Sons' Tacony Works."
Hexamer General Survey #955 (1875) "Henry Disston & Sons' Tacony Works."
Hexamer General Survey #1266 (1878) "Henry Disston & Sons' Tacony Works."
Hexamer General Survey #1407 (1879) "Henry Disston & Sons' Tacony Works."
Hexamer General Survey #1763-1764 (1883) "Henry Disston & Sons' Tacony Works."
© Edwin T. Freedley, Philadelphia and its Manufactures (1867), p. 306.