What Was in Sandusky's Secret Plane Making Room?

Joseph A. Montgomery's 1890 patent for a machine that beveled the tips (b) of bench plane wedge grips.

Visitors to the Sandusky Tool Company in the late 1800s would have been awed by its sheer size. Spread out over three and a half acres were five massive lumber sheds and dozens of buildings for steaming timber, forging, blacksmithing, box making, painting, shipping, and packaging, all connected by a network of hand cart tracks. In the main building, a 160 hp steam engine powered saws, planers, and a machine shop on the first floor, a turning shop on the second floor, and “beaters” and mortising machines on the third floor, where 36 planemaker’s benches turned out 1,200 planes a day.¹

But there was one room on the third floor that would have been off limits to visitors. All bench planes passed through this “special private room,” as one company manager described it. When they came out, the miter in the plane’s throat, and the bed the iron sits on, was perfectly cut. But how it was done was a secret. As the manager explained, “This special room, I speak of, is for the purpose of keeping other manufacturers from learning the secrets of this particular machine and its operation.”²

Commercial plane making in the United States has its roots in the early 18th century, in quiet workshops where craftsmen made each tool by hand. By the late 1800s, plane making had become a global business, with companies like Sandusky shipping tools as far away as Australia, India, and China. Firms needed a manufacturing process that was streamlined, repeatable, and, above all, fast. They needed machines.

The 19th century saw the invention of hundreds of new tools and machines for sawing and planing. Large firms, like Sandusky, the Ohio Tool Co., Greenfield Tool Co., and the Chapin family’s companies, as well as some smaller companies relied on these machines, which were often powered by water or steam engines. Small, general-purpose hand- and foot-powered machines were also used in plane making. Roy Underhill has a great demonstration of these circular saw, boring and mortising machines. (Boring machines are likely the source of the uniform point marks often found in the bottom of tote mortises.)

Joseph A. Montgomery's patent for a machine that shaped the throat on moulding planes and some types of joinery planes.

Planemakers also needed specialized machines, and specifically something that could cut the diagonal surfaces inside a bench plane’s throat. As Sandusky Tool Superintendent Joseph A. Montgomery explained in 1890, power mortising machines weren’t sufficiently accurate to cut the back of the throat that the iron rests on, also known as the bed. That work was done by hand, but, he wrote, “such hand-work was slow and expensive and seldom entirely satisfactory.”³

Sandusky's "true mechanical genius"

The founders of Sandusky Tool knew they needed someone who could solve these kinds of mechanical problems when they were getting ready to launch their company in 1869. Montgomery, who was known as “a true mechanical genius of his time,” was the obvious solution. Montgomery began making planes in Boston in the mid-1840s before moving to Columbus, Ohio, where he was involved in the founding of the Ohio Tool Co. in 1851. He joined Sandusky Tool and worked there until his death in 1899. Because of his role in the founding of both Sandusky and Ohio Tool, he’s ranked as one of most influential planemakers of the 19th century.⁴

While at Sandusky, Montgomery patented four plane making machines (see American and English Plane Making Machinery Patents below), including one that solved the bedding problem he described above. His machine for hollowing out wedges reduced the amount of time it took to make a wedge to just a few seconds, allowing a worker to turn out about 10 wedges per minute.⁵

Another machine simplified the time-consuming process of shaping the throats of rabbet planes, moulding planes, and other similarly sized planes. Workers built custom jigs, or patterns as Montgomery called them, to hold the stock for these types of planes at the correct angle as they passed over a table saw. Each type of plane required its own pattern. As Montgomery pointed out, not only could the patterns vary depending on the worker, they would warp and wear out over time. “These patterns had to be made with great care and accuracy,” he wrote, “and each workman was supposed to provide his own patterns, so that a plane-factory was likely to be cumbered with absolutely cart-loads of these patterns.”⁶

His machine eliminated the need for patterns and resulted in a final product made with “perfect uniformity,” as he put it. Montgomery also patented a tool for shaping the ends of fence pickets and was likely the creator of many other un-patented tools. Did he invent the machine in Sandusky’s special room? His “Machine for Dressing the Throats of Wooden Planes” certainly sounds like it, but as far as I know, the company never revealed what it was. It was a secret they took to the grave.

Circular saw marks found in planes made by Dewey & Newton. Photo: Plane Talk.

The Ohio Tool Co. also had plane making patents. But these kinds of machines weren’t just used by the large firms. In 1857, Vermont planemaker Henry S. Dewey received a patent for a “Machine for Cutting the Throats of Carpenters’ Plane-Stocks.” The machine used a small circular saw to cut the bed for the iron. It left behind marks that you can still find in planes made by Dewey and his partner Levi W. Newton. While the machine clearly worked, their partnership appears to have lasted only one year. (The Komori Small Plane Factory in Japan also uses a small circular saw to bed their irons.)⁷

A rare English patent

Large British planemakers like Greenslade and Mathieson may have developed their own machinery, but I’ve been able to track down only one patent from the UK (see American and English Plane Making Machinery Patents below). It was filed by Thomas Slater, a London optical technician, and Joseph Tall, a toolmaker, in 1854. It covered three different machines: one that used parallel circular blades to cut a plane stock to the correct width, one with blades set at opposing angles that mortised the throat, and another with vertical blades that cut the cheeks in the throat.⁸

Slater and Tall partnered with Robert Neilson Tennent and made planes under the name “R. N. Tennent” at Pembroke Wharf in Islington in London. The men dissolved their partnership in November 1855. When Tennent died in May 1856, The Gazette referred to him as a “patent plane manufacturer.” (Goodman’s British Planemakers 4th ed. doesn’t have an entry for this Tennent. There is an entry for a Robert Tennent, but he was active in Scotland 36 years after Robert Neilson Tennent’s death.)⁹

Thomas Slater and Joseph Tall's patented machines that cut the sides of a plane stock (left) and mortised the throat (right). Image: The Practical Mechanic's Journal 7, April 1854-March 1855.

It might be possible to trace where at least one of Slater and Tall’s machines ended up next. In 1858, the Sheffield plane making firm Wm. Brookes & Sons purchased eight “extensive and beautiful” plane making machines, as a local newspaper described them. The newspaper was among a group of city officials and business leaders who were invited to Brookes’ Howard Works on Carlisle Street to see how each machine worked. The first cut a plane stock to its rough dimensions. The second, “by the action of two circular cutters, planes their sides,” the same as the Slater and Tall invention. The third cut the stock to the correct length.¹⁰

“Then comes a very curious machine for sinking the mortice. Two chisels, from opposite directions, work to and from a point in succession,” the newspaper explained. This is a concept that’s similar to the mortiser used by the Komori Small Plane Factory in Japan, but it’s not the same as the Slater/Tall invention, where the blades worked simultaneously.¹¹

Another machine used a “minute circular cutter” to create the mouth and an even smaller circular blade to cut the mortise for the tote. The next machine cut the abutment in the throat. Slater and Tall’s description of their third invention is so convoluted and garbled that I honestly can’t tell if it’s the same as this Brookes machine. Then the iron was bedded. A final machine made the wedge. When the machines were auctioned off in 1868 following Brookes’ bankruptcy, they were described as “valuable patented plane making machinery.”¹²

While American and British plane making machines took care of much of the manufacturing process, finishing the tools was still done by hand. At Sandusky, each finisher completed about 200 planes a day. And some planes, like plows, likely required a great deal of hand-work, that “slow and expensive and seldom entirely satisfactory” work Montgomery complained about. If they could have automated every step, every plane, they would have.¹³

The mechanization of plane making allowed companies like Sandusky and Ohio Tool to reach global markets on a scale that would have been unfathomable to those early 18th century craftsmen in their quiet workshops. But it was a near-fatal blow to the craft of plane making. It would take nearly a century for those skills to be rediscovered by modern makers. But for the men of the late-19th century, it was a lost profession. As a former apprentice planemaker recounted as he looked back on his life, “When the age of progress made planes by machinery, this occupation too was swept like sand from under my feet.”¹⁴

American and English Plane Making Machinery Patents

• Thomas Slater, Joseph Tall (R. N. Tennent, London, UK), Improvements in the construction of planes and in cutting apparatus, and in the machinery or apparatus employed therein, 12/30/1854, #2761. The Practical Mechanic’s Journal 7, April 1854-March 1855 has detailed engravings of the machines.
• Henry S. Dewey (Newton & Dewey, Bethel, VT), Machine for Cutting the Throats of Carpenters’ Plane-Stocks, 3/31/1857, #16,954.
• Francis B. Marble (Ohio Tool Co., Columbus, OH), Improvement in Machines for Dressing the Throats Of Plane-Stocks, 2/14/1865, #46,372.
• John Richards (possibly Ohio Tool Co., Columbus, OH), Improvement in Machines for Mortising Plane-Stocks, 2/14/1865, #46,392.
• Charles Carter (Ohio Tool Co./H. Chapin’s Son, New Hartford, CT), Improvements in Mortising-Machines, 10/6/1868, #82,692.¹⁵
• Benjamin F. Barker, Improvement In Machines For Making Plane-Stocks, 9/23/1879, #219,900.
• Joseph A. Montgomery (Sandusky Tool Co., Sandusky, OH), Machine for Scooping Wedges for Planes, 7/1/1890, #431,380.
• Joseph A. Montgomery (Sandusky Tool Co., Sandusky, OH), Machine for Dressing the Throats of Wooden Planes, 7/1/1890, #431,381.
• Joseph A. Montgomery (Sandusky Tool Co., Sandusky, OH), Machine for Sawing the Mouths of Molding Planes, 7/1/1890, #431,382.
• Joseph A. Montgomery (Sandusky Tool Co., Sandusky, OH), Machine for Beveling the So-Called Wedge-Grips of Wooden Planes, 7/1/1890, #431,383.

A 1914 photo of a machine Stanley Rule & Level Co. used to mortise the throats in their wood-bottomed transitional planes. Photo: Plane Talk.

Interested in more stories about plane making companies?

• 'I want to Knock this Man out of the Market'
• What Was in Sandusky's Secret Plane Making Room?
• The Ohio Tool Co. (Briefly) Paid Its Convict Workers
• How to Run a Plane Factory in 1853 (It Was Surprisingly Complicated)

Editor’s note: The English patent section was updated 7/1/2025 to provide more information about the Goodman’s entry. Footnote 8 was added so that I could include a link to Slater’s background.