How Mount Rushmore Was Built: A Monumental Engineering Feat

Mount Rushmore, one of the most iconic landmarks in the United States, stands as a towering tribute to the nation’s history and ideals. Carved into the granite cliffs of South Dakota’s Black Hills, the monument features the faces of four U.S. presidents—George Washington, Thomas Jefferson, Theodore Roosevelt, and Abraham Lincoln—each chosen for their contributions to the country’s founding, growth, development, and unity.

Mount Rushmore’s origins trace back to Doane Robinson, a South Dakota historian who envisioned a massive sculpture to boost tourism in the state. Initially, Robinson suggested carving famous figures of the American West into the Black Hills, but sculptor Gutzon Borglum proposed a broader theme to honor America’s history.

Construction of the monument began in 1927 and spanned 14 years, involving over 400 workers and an array of innovative techniques. Despite the challenges posed by weather, the hardness of the granite, and the technological limitations of the era, the team successfully completed the faces of four presidents, each standing 60 feet tall.

The Vision Behind the Memorial

The idea for Mount Rushmore was conceived in the 1920s by sculptor Gutzon Borglum, who sought to create a monumental artwork that would honor key figures in American history. Borglum chose to immortalize Presidents Washington, Jefferson, Roosevelt, and Lincoln because of their roles in shaping the nation’s founding, expansion, and development. The site was selected due to its prominent location and the quality of the granite, which was ideal for large-scale sculpture.

Planning and Design

Before the towering faces of George Washington, Thomas Jefferson, Theodore Roosevelt, and Abraham Lincoln adorned the Black Hills of South Dakota, Mount Rushmore existed only as a bold concept in the mind of sculptor Gutzon Borglum. Transforming this concept into reality required extensive planning, artistic vision, and collaboration.

The Birth of an Idea

The idea for Mount Rushmore originated with Doane Robinson, a South Dakota historian. Robinson envisioned a monument that would promote tourism to the Black Hills region. Initially, Robinson proposed carving prominent figures from the American West, such as explorers or Native American leaders, into the granite spires known as the Needles. However, Borglum, already an acclaimed sculptor, believed the project should represent broader themes of American history and unity.

Borglum proposed focusing on four U.S. presidents who symbolized foundational ideals:

• George Washington for the birth of the nation.
• Thomas Jefferson for the expansion through the Louisiana Purchase.
• Theodore Roosevelt for industrial growth and conservation efforts.
• Abraham Lincoln for the preservation of the Union during the Civil War.

Choosing the Site

Mount Rushmore was selected for its stable granite composition and visibility. The granite was durable enough to withstand the passage of time, yet pliable enough to carve. Its southeastern exposure ensured ample sunlight would illuminate the monument, enhancing its visibility to visitors.

From Vision to Blueprint

Borglum’s approach to design was meticulous. He created several sketches and models to refine his vision. These included a 1:12 scale plaster model that served as the blueprint for translating the design onto the mountain. Each inch of the model represented one foot of the actual sculpture, enabling precise scaling.

To maintain proportion, Borglum developed an innovative measurement system. Using a pointing machine, his team transferred exact coordinates from the model to the mountain. This ensured the massive project retained the detailed features of the presidents’ faces, from Washington’s prominent nose to Roosevelt’s glasses.

Challenges in Design

While the initial design was grander, including torsos and hands, budgetary constraints and the difficulty of carving granite led to a more simplified focus on the faces. Additionally, Borglum and his team had to adapt to natural imperfections in the mountain’s surface, often revising elements of the design to accommodate cracks or discolorations in the rock.

Tools and Techniques Used

Constructing Mount Rushmore was no small feat. The monumental task required a combination of ingenuity, specialized tools, and innovative techniques to carve the 60-foot-tall faces of four U.S. presidents into the granite face of the Black Hills in South Dakota. Let’s take a closer look at the key tools and methods used during this iconic project.

Primary Tools

1. Dynamite:
   Dynamite was the cornerstone of the sculpting process, accounting for nearly 90% of the material removal. Expertly placed charges removed large sections of granite with surprising precision, thanks to meticulous planning. Workers drilled holes to insert dynamite, ensuring controlled blasts that adhered to the desired contours of the sculptures.
2. Jackhammers:
   Pneumatic jackhammers, powered by air compressors, were essential for shaping and detailing the rock. These tools were highly effective for rough carving after dynamite had done its job. Skilled operators used jackhammers to create the general outlines of the presidents’ features.
3. Hand Drills and Chisels:
   For fine detailing, hand drills and chisels were indispensable. These tools allowed sculptors to add intricate details like the wrinkles on Abraham Lincoln’s face or the edges of Theodore Roosevelt’s glasses. The painstaking effort required for this final stage demanded both patience and artistic precision.
4. Bosun’s Chairs and Rope Systems:
   Safety and mobility were paramount on the vertical rock face. Workers used bosun’s chairs, suspended by ropes, to access specific areas of the sculpture. These systems allowed them to hang securely while carving the towering granite surface.

Innovative Techniques

1. Honeycombing:
   One of the most ingenious methods employed was “honeycombing.” This technique involved drilling a series of closely spaced holes into the granite. By doing so, workers weakened the stone, making it easier to remove in smaller, controlled chunks. This approach was crucial for achieving fine detail without risking damage to adjacent areas.
2. Plaster Models and Pointing Machines:
   A 1:12 scale plaster model was created to guide the work on the mountain. Sculptors used a pointing machine, a mechanical device that translated measurements from the model to the granite. This method ensured proportional accuracy across the massive sculpture.
3. Trial and Error:
   Despite their meticulous planning, adjustments were frequently made. The team often improvised when unexpected cracks or inconsistencies in the granite surface emerged.

The Pointing Machine: Ensuring Precision on a Monumental Scale

One of the most innovative tools used during the construction of Mount Rushmore was the pointing machine, a device adapted from traditional sculpture techniques. This tool was critical in scaling the detailed features of the presidents’ faces from the small plaster model to the mountain’s massive granite canvas.

How the Pointing Machine Worked

The pointing machine consisted of a series of rods, hinges, and measuring devices that could record precise coordinates from the plaster model and translate them to the granite surface. Here’s how it functioned:

1. Creating Reference Points:
   Sculptors first measured specific points on the 1:12 scale plaster model. These points—such as the tip of Washington’s nose or the corners of Roosevelt’s glasses—were identified and marked.
2. Scaling Up:
   Using the 1:12 ratio, the pointing machine calculated the exact corresponding location on the mountain, magnifying each measurement 12 times. Workers would then drill small holes into the granite at these marked points to guide the carving process.
3. Maintaining Accuracy:
   The pointing machine’s measurements ensured that the overall proportions of each face remained consistent. This was particularly important for features that needed to be seen clearly from a distance, such as the deep set of Lincoln’s eyes or Jefferson’s mouth.

Challenges in Using the Pointing Machine

While the pointing machine was a remarkable tool for its time, it was not without limitations:

• Labor-Intensive Process: Taking measurements and transferring them to the granite required significant time and precision, especially when working on the sheer cliff face.
• Granite Imperfections: Natural flaws in the rock, such as cracks or color variations, sometimes forced workers to adjust the measurements and rework certain areas.
• Coordination Across Teams: Multiple teams worked simultaneously on different parts of the sculpture, making it essential to cross-check measurements to avoid discrepancies.

Challenges Faced: Weather, Precision, and Technological Limitations

Constructing Mount Rushmore was as much a battle against nature and technology as it was a creative endeavor. The team faced significant challenges, from unpredictable weather to the technological constraints of the early 20th century. Despite these hurdles, their perseverance transformed a rugged granite mountainside into an enduring symbol of American history.

Weather and Environmental Conditions

The location of Mount Rushmore in the Black Hills presented unique environmental challenges:

• Harsh Winters: Freezing temperatures during South Dakota’s winters often brought construction to a halt. Workers struggled to maintain equipment and their own safety in such conditions.
• Summer Heat: On the flip side, scorching summer days made the job physically exhausting, especially for laborers operating heavy equipment under the sun.
• Unpredictable Storms: Sudden storms posed risks to both workers and the integrity of the unfinished sculpture. Strong winds could make operating on the mountain’s steep face particularly dangerous.

Achieving Precision at Scale

Creating 60-foot-tall faces with lifelike detail was a monumental challenge, particularly given the tools available:

• Granite Hardness: Granite’s durability made it ideal for a lasting monument but incredibly difficult to carve. Workers had to strike a balance between removing enough material for detail and avoiding cracks or over-carving.
• Scaling the Design: Translating the 1:12 scale plaster model to the mountain required incredible precision. Any error in measurement could result in disproportioned features that were visible from afar. The pointing machine helped, but it was still a slow and painstaking process.
• Detail Work at High Elevation: Adding intricate details like Roosevelt’s glasses or Lincoln’s beard required workers to operate at precarious heights, often suspended in bosun’s chairs. Even minor mistakes could jeopardize the project’s progress.

Technological Limitations

The 1920s and 1930s were decades of technological progress, but the tools available to Mount Rushmore’s workers were still rudimentary by today’s standards:

• Manual Labor: While pneumatic tools like jackhammers helped, much of the detail work relied on hand tools, requiring enormous effort and skill.
• Limited Machinery: The heavy equipment needed to move materials and support workers was basic by modern standards, meaning tasks often took longer and were more labor-intensive.
• Communication and Coordination: Without modern communication tools, coordinating a team of 400 workers spread across a massive vertical worksite was a logistical challenge. Signals and visual cues were often the only way to convey instructions.

Unforeseen Setbacks

Natural imperfections in the granite presented ongoing issues:

• Cracks in the Rock: Workers had to adjust the design on the fly to avoid cracks that could undermine the structural integrity of the sculpture. For example, Jefferson was originally planned to the left of Washington but was moved after discovering unsuitable rock in that area.
• Material Removal Errors: Occasionally, workers removed too much material, requiring creative adjustments to the design. Each correction increased the time and complexity of the project.

Safety Risks

Despite the dangerous conditions—working at great heights, operating heavy machinery, and using explosives—there were surprisingly no fatalities during the project’s construction. This remarkable safety record speaks to the discipline and ingenuity of the workforce, but it doesn’t diminish the constant risks they faced.

Completion and Legacy

Mount Rushmore was officially completed in 1941, though some details, such as the planned inscriptions and the full sculpting of Jefferson’s face, were never finished. Despite its incomplete state, the memorial became an iconic symbol of American history and ingenuity. Today, visitors from all over the world marvel at the scale and craftsmanship involved in creating this landmark.

Amazing Facts About the Construction of Mount Rushmore

The Scale is Incredible
Each of the four presidential faces on Mount Rushmore is about 60 feet tall—roughly the size of a six-story building. The noses alone measure 20 feet long!

Dynamite Played a Key Role
Approximately 90% of the rock was removed using dynamite. Workers would drill holes into the granite, pack them with dynamite, and blast away large sections of rock. This allowed the crew to remove massive amounts of material quickly and efficiently.

It Took 14 Years to Complete
Construction on Mount Rushmore began in 1927 and was officially completed in 1941. Despite interruptions due to weather, funding shortages, and the death of the sculptor, it took a dedicated team to finish the project.

Borglum’s Vision Was More Ambitious
Gutzon Borglum originally envisioned a more expansive design, including carvings of the presidents down to their waists, as well as a large archway. Unfortunately, the project was never fully completed due to lack of funds and Borglum’s death.

No Fatalities During Construction
Despite the dangerous working conditions (including high-altitude work and dynamite usage), there was only one fatality during the entire 14-year construction period.

The Workers Had to Be Suspended on Ropes
Workers carved the monument while suspended on ropes from wooden scaffolding. It was an incredibly dangerous job, with many of the workers facing heights of more than 500 feet above the ground.

Gutzon Borglum Worked from a 1:12 Scale Model
Borglum’s initial model of Mount Rushmore was only 1/12th the size of the actual monument. The workers used this model as a reference to carve the massive figures in the mountainside.

Over 400 Men Worked on the Project
At various times during construction, there were over 400 workers involved in the project, including carvers, miners, and laborers. Many were local men hired from nearby areas.

The Memorial Was Nearly Lost
During the Great Depression, funding for the project was at risk. The U.S. government stepped in to provide financial support, and the memorial was saved from potential abandonment.

Borglum’s Son Finished the Monument
After Gutzon Borglum’s death in 1941, his son, Lincoln Borglum, oversaw the completion of the project, though it was never fully finished as initially planned.