The Fastener That Started It All: The Original Huckbolt®
Huck Manufacturing has had innovation in its DNA from the very beginning. In the early 1930's, founder Louis C. Huck identified a production bottleneck at Dornier. His solution became the first Huck structural blind fastener.
The original Huck® blind rivet was a game changer in improving production speed. It was designed for single-sided installation. Even better, it installed using an easy-to-use tool that kept costs down and broadened the available labor pool.
Archival photo of an early Huck® structural blind fastener
Less than a decade after Lou Huck was granted a patent for it, the Huck rivet was being installed in every B-24 bomber that came off the assembly line at Ford's Willow Run factory in Detroit. It's not a stretch to say that the fastener's ease of installation contributed significantly to the stunning improvement in assembly speed the plant experienced.
But Willow Run was just the beginning of Huck's World War II production story - both for the war effort and for Huck Manufacturing.
Innovative Production Was Key to the War Effort
Photograph of a German Luftwaffe crew relaxing beside the formiddable Bf 109 fighter
By the time World War 2 began, the German Luftwaffe was the best air force in the world. Its pilots were highly skilled, flying some of the most advanced aircraft in the world. The Luftwaffe’s main challenge was the loss of pilots during the air war and the Reich’s inability to repair manufacturing plants, transportation infrastructure, and fuel plants fast enough under the pressure of the Allied bombing campaign in the last year of the war.
The story of the US Army Air Corps is almost the inverse of that of the Luftwaffe. When war began, the Americans were woefully underequipped, with a fledging bomber force that sent green bomber crews to war.
The air war strategy developed by the “Bomber Mafia” depended on heavily armed bombers like the B-17 Flying Fortress defending themselves during formation flying. This was a theory that got tested in real, brutal conditions, but it was also necessitated by limited production capacity in the US at the outset of World War II.
Factories for producing war materiel in quantity just didn’t exist prior to the bombing of Pearl Harbor and as they came online in 1942 and 1943, the War Production Department had to make difficult calls on which products to produce and where to send them.
Photograph of a B-24 production line at Willow Run, from the National Archives
Production facilities like Ford’s Willow Run plant were built quickly. The US started turning out ships, vehicles, and planes in record numbers. These huge increases in production were due in no small part to incredible advances in innovation in the areas of product design and process efficiency.
In short order, the United States and her Allies were able to replace equipment losses fast enough to gain air superiority in the European theater and to support key offensives like the D-Day landings in Normandy.
Production Needs Trumped Technological Specifications
The Allies didn’t just fight in Europe though. The bombing of Pearl Harbor drew the United States immediately into war with Japan. Luckily, the U.S. Navy was better equipped than the U.S. Army, even considering the losses suffered on December 6, 1941.
Photograph of the USS Pennsylvania, a battleship, and three cruisers at sea
Established 150 years before the US Army Air Corps, President Franklin D. Roosevelt considered the Navy to be the country’s first line of defense. Even in the wake of the Great Depression, Roosevelt managed to push through funding to develop and build new naval equipment. Part of this funding went to developing new naval aviation programs.
Requirements for Navy planes were slightly different than those used by the Air Corps. While both needed to find ways to fly long distances, Navy planes needed to be robust enough to withstand carrier landings.
Photograph of a biplane from the National Archives, ca. 1918
Showing just how quickly technology changed by the end of World War 2, one of the original fighter planes in the Pacific theater, the Grumman F4F Wildcat, was originally designed as a biplane in the early 1930’s. It was quickly redesigned as technology progressed, but never managed to meet the base specifications for speed that were set forth by the Navy. Luckily for Grumman, its competitor was unable to produce its winning design, and the Navy began to order the Wildcat at the end of 1939.
Despite its “vintage” roots, the Wildcat saw service with the Navy in the battles of the Coral Sea and Midway and it was sold to the British Navy for protecting convoys in the Atlantic, defending Scapa Flow, and aiding the Greek resistance in the Mediterranean.
When “Good Enough” Needs to become Better
The F4F Wildcat fighter was a tough plane, able to be flown and landed after suffering significant combat damage. But it was less agile than the Mitsubishi Zero it often flew against and had manual landing gear that pilots engaged and retracted by manually turning a hand crank.
Interestingly, this was the beginning of the jet era. The Navy F4 Corsairs were deployed into the Pacific theater around the same time as the Wildcat. These were heavily armed jets that flew over 400 miles an hour – the first single engine plane to do so.
Photograph of an F6F Hellcats preparing to take off from the deck of the USS Yorktown, from the National Archives
Grumman needed to do better than the Wildcat, and they did.
In October 1942, the company had its first flight test of the next generation of Wildcat, the fighter they called the F6F Hellcat (Fun fact: Grumman initially wanted to call their new fighter “Tomcat” but this was deemed too risqué for the time. They had to wait 25 years but finally got to use the name with a strike fighter they called the F-14 Tomcat.). The Hellcat had more armor, more guns, and a greater range than its predecessor.
Like the Wildcat, the Hellcat could take significant combat damage and still fight. Both planes were easier to land on aircraft carriers than the Corsair, so the Corsair became more of a land-based fighter while the Hellcat reigned supreme over water. It was widely considered to be the most successful fighterv in World War 2, providing its pilots with the brute power needed to counter the Mitsubishi Zero’s agility.
Archival photo of woman installing Huck fasteners, believed to be at the Willow Run plant
The Hellcat was also a marvel of production efficiency. The fighter was only made for 30 months, with production shutting down in November of 1945. At full production, Grumman averaged 16 planes a day off their assembly line. The company was manufacturing so quickly that the Navy asked them to slow down.
Huck’s Connection with the Grumman F6F Hellcat
Photograph of the founder of Huck Manufacturing, Louis C. Huck
Little is known about how Louis Huck came to be involved with Grumman, the maker of the F6F Hellcat.
Lou was an engineer who received his degree from Cornell University, not far from Grumman’s Bethpage, New York manufacturing plant. Enrollment in Cornell’s mechanical engineering program grew rapidly in the early 1900’s and aeronautics was a documented focus as early as 1910.
After graduating from college in 1917, Huck joined the U.S. Navy. It was there, in the waning days of World War I, that it is believed he learned to fly planes.
His career took him from naval aviation to the automotive industry. But Huck never lost his love of flight. This was the Golden Age of Air Travel. Barnstormers traveled the country, performing stunts far above the heads of spectators. Charles Lindbergh made the first nonstop flight from New York to Paris. Air travel between cities, unremarkable today, was glamorous enough to be newsworthy.
It was a small community as well. Pioneers in the design and manufacture of aircraft would have been connected one way or another. And with the onset of World War 2 and the urgent need to speed up production of military aircraft, innovative ideas would have been noticed.
Photograph of F6F pilots on the USS Lexington in November 1943, from the National Archives
However it happened, Huck and his structural blind fastener got noticed by Grumman. The Huck blind rivet was used in the construction of the F6F Hellcat fighter, a plane so trusted that many WW2 fliers preferred it to the jets that were the future of naval aviation.
Reputation Matters
Louis C. Huck’s resourcefulness wasn’t limited to his structural blind fastener. Clearly well thought-of by his peers, Huck was called to consult on a problem that vexed engineers, designers, and strategists.
In World War 2, aircraft needed to travel long distances in both the Pacific and Atlantic theaters. There was a critical need, particularly early in the war, to find ways of extending the fuel range of military aircraft.
Fuel range was a truly deadly problem. As the AppleTV+ series Masters of the Air superbly demonstrates, heavy bombers in the European theater – particularly early on in the air war – often flew deep into enemy territory without escorts because the fighters didn’t have enough fuel to accompany them.
The problem also existed in the Pacific theater. There it was scouting missions that created the greatest need for increased flight range. The US Navy began researching solutions well before WW2 began.
One solution to expand the range aircraft could fly was to utilize drop tanks for fuel. These tanks provided extra reservoirs of fuel that attached to the wings or the fuselage of a plane. Once the fuel was consumed in flight, the pilot could jettison the tanks to reduce weight and improve maneuverability.
108 gallon English-made drop tank at the Imperial War Museum Duxford
Early in the war, the British developed drop tanks were made from a type of paper mâché. This paper and glue concoction was waterproof but would start to leak as the fuel interacted with the glue.
Later WW2 aircraft drop tanks were constructed from steel, but they still experienced problems with leaking at the seams. Not only did this mean the planes couldn’t fly as long, it meant pilots could never know exactly how much extra flight time they’d gain.
There were also issues with the mechanisms that were used to fasten the droppable wing tanks. Once the fuel was used up, pilots would sometimes have trouble releasing the tanks. Masters of the Air illustrates this well in one of the final episodes.
The Fastener that Changed the World
Legend has it that Huck headed east on December 2, 1944 to take a look at the droppable wing tanks the US Military so desperately needed. It was unusually cold that month, with significant snowstorms across the northeastern United States.
In the European theater, the Allies were dug into foxholes in the Ardennes, fighting off what would become Hitler’s last major offensive. In the Pacific, Japan initiated kamikaze attacks and the US Navy had begun the naval bombardment of Iwo Jima. The Allied victory was still not certain.
Design had begun on a steel drop tank that assembled by fastening two halves together. It’s very likely that Huck was called in to consult either because the manufacturer was looking to improve speed of assembly or because they saw conventional fasteners loosen under vibration.
Lou attended the meeting and analyzed the problem. When it was over, he boarded a Wabash passenger train, sitting in car #2, and headed home to Detroit. It was mere weeks before Christmas.
One of the original sketches of the Huckbolt®, used as part of the patent filing
When inspiration struck, Lou grabbed a napkin, got out his pen, and sketched his idea for what would become the original Huckbolt®.
Many wartime innovations were soon to be outpaced by the very technologies they advanced. But the Huckbolt® was a revolutionary piece of engineering that quickly became the go-to problem-solver in industries ranging from ships and bridges to railcars, track, heavy trucks, construction equipment, wind, solar, and more. Today, the Huckbolt® is still in use all over world – both in its original design and in new iterations like the Bobtail.
Frequently Asked Questions
What is a HuckBolt®?
A Huckbolt® is best explained as bolt and a nut. Instead of the bolt, a Huckbolt® has a pin with lock grooves. Instead of a nut, the Huckbolt® uses a collar that gets locked into the grooves during the installation process. It’s a system that forms a permanent lock which is resistant to vibration loosening in a way conventional fasteners aren’t.
What makes the Huckbolt® so successful?
Instead of using torque, the Huckbolt® uses a unique installation method to fasten with direct tension. This delivers controllable clamp that makes it ideal for a wide range of fastening applications. Its also vibration resistant, due to a unique installation process called “swaging”.
What is swaging?
Swaging is what happens when the installation tool essentially presses, or re-forms, the collar into the grooves of the pin. This results in a permanent fastener that does not vibrate loose.
