Milton in Halton Region, Ontario — Central Canada (North America)

The P.L. Robertson Manufacturing Company

Photographed by Tim Boyd, August 17, 2025

1. The P.L. Robertson Manufacturing Company Marker

Inscription. Click to hear the inscription.

The first firm in the world to produce socket-head screws, the P. L. Robertson Manufacturing Company was formed in Hamilton in 1907 and relocated here the following year. It was established by an Ontario inventor Peter Lymburner Robertson and using an ingenious process he had developed to punch square holes into cold metal, it manufactured the innovative new screw for industrial markets. In its first two decades the company steadily expanded operations. By 1930, when the last patent on the Robertson screw and the equipment used in its manufacture expired, the firm had already begun to diversity its products. Now operated as the Robertson Whitehouse Company, it has become one of the largest manufacturers of light fasteners, including the original Robertson screw, in North America.

Première firme au monde à produire des vis à tête creuse, la compagnie P. L. Robertson ouvre ses portes à Hamilton en 1907, puis s'établit ici l'année suivante. Fondée par un inventeur ontarien, Peter Lymburner Robertson, qui avait mis au point un ingénieux procédé pour percer des trous carrés dans du métal froid, elle fabrique cette

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nouvelle vis pour l'industrie Pendant les vingt premières années, la compagnie connaît une expansion progressive. Avant 1930, date d'expiration du dernier brevet pour la vis Robertson et l'équipement employé dans sa fabrication, la firme commence déjà à diversifier ses produits. Connue maintenant sous le nom de Robertson Whitehouse, elle est devenue en Amérique du Nord l'un des plus importants fabricants d'attaches légères, dont la vis Robertson originale.

Erected by Ontario Heritage Foundation.

Topics and series. This historical marker is listed in this topic list: Industry & Commerce. In addition, it is included in the Canada, Ontario Heritage Trust series list. A significant historical year for this entry is 1907.

Location. 43° 30.7′ N, 79° 53.525′ W. Marker is in Milton, Ontario, in Halton Region. It is on Bronte Street North 0.3 kilometers north of Victoria Street, on the right when traveling north. Touch for map. Marker is at or near this postal address: 125 Bronte St N, Milton ON L9T 2N8, Canada. Touch for directions.

Regionally, this marker is in Greater Toronto,

specifically on the Golden Horseshoe,

in the Hamilton-Halton-Brant

The P.L. Robertson Manufacturing Company Marker [français] image. Click for full size.

Photographed by Tim Boyd, August 17, 2025

2. The P.L. Robertson Manufacturing Company Marker [français]

Area,

and specifically in the Toronto Metropolitan Area.

It is also in Central Canada.

Globally, it is in North America,

on the Great Lakes,

in the Western Hemisphere,

in the Western World,

and in the Anglosphere.

Historically, it finds itself in what was once a British colony,

the Viceroyalty of New France,

the Haudenosaunee (Iroquois) Confederacy,

and Rupert’s Land.

Other nearby markers. At least 8 other markers are within 5 kilometers of this marker, measured as the crow flies: The Fred W. Armstrong Arena (approx. 0.6 kilometers away); Milton Cenotaph (approx. 0.6 kilometers away); Milton’s World War I Field Gun (approx. 0.6 kilometers away); Milton’s Commemorative Cenotaph (approx. 0.6 kilometers away); Victoria Park (approx. 0.7 kilometers away); Halton County Court House (approx. 0.7 kilometers away); Former Milton Town Hall (approx. 0.8 kilometers away); Milton Outlier (approx. 3.8 kilometers away). Touch for a list and map of all markers in Milton.

The 1909 patent for P.L. Robertson’s screw image. Click for full size.

3. The 1909 patent for P.L. Robertson’s screw

Source: Roberstonscrew.com

Photographed by Tim Boyd, August 17, 2025

4. The P.L. Robertson Manufacturing Company Marker

Facing northeast on Bronte Road

The original Robertson Manufacturing plant, in 2025 image. Click for full size.

Photographed by Tim Boyd, August 17, 2025

5. The original Robertson Manufacturing plant, in 2025

Credits. This page was last revised on August 19, 2025. It was originally submitted on August 18, 2025, by Tim Boyd of Hamilton, Ontario. This page has been viewed 127 times since then and 31 times this year. Photos: 1, 2, 3, 4, 5. submitted on August 18, 2025, by Tim Boyd of Hamilton, Ontario. • Andrew Ruppenstein was the editor who published this page.