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Nathan Lester & William (Bill) Morris Lester – The Origins Of Modern Injection Molding And Pyro Plastics Company

By Alan Bussie

Second Edition Notes

In the first edition, credit was given to one man for the first modern injection molding machine. This may or may not be true; evidence gathered over the last 3 years paints a more complicated picture. This revision is not an effort to take credit away from anyone but to give it where due.

I would like to thank artist and friend Michael Boss, Peter van Lune, Marsha Frantisak and the “Industry Watch” article cited below. Without these sources this article would not be possible. Marsha is niece of William Lester and granddaughter of Nathan Lester. Please note that any photos without credits are from the internet. If you did not receive credit or if any of these photos are copyrighted, please contact me for credit or removal. Thank you-AB

Introduction

Pyro is not the most famous of the US plastic model companies. Die-hard collectors know the name well, but even fewer are aware that Pyro’s founder, William Lester, was an entrepreneur, innovator and inventor. Furthermore, William learned molding from his father, Nathan Lester. Both of these men had a hand in inventing the modern plastic injection molding machine, which completely revolutionized American plastics manufacturing. Some details are lost to history but enough is known to create a rough portrait.

Modern Injection Molding Machine (courtesy Western Kentucky Plastics)

Biography

William’s father, Nathan Lester, was born in 1884 in Minsk, Russia and immigrated in 1905. Bill’s mother, Mrs. Gussie Lester, was also born in Russia in 1884. We do not know much else about his youth, but Nathan was a brilliant man and entrepreneur who reached the top of his industry. He owned Lester Die & Machine Company of Cleveland (1920s to ?, referred to as ‘Lester Tool’ later), Lester-Phoenix Die Casting Machines in Cleveland (30s/40s+), one of the leading die-cast companies in the USA. At least one trade catalog (dated 1941) of Lester-Phoenix Die has survived. He also owned Lester Engineering and held numerous patents. This is a small sample:

In the book “The Story of New Jersey(1945),” Nathan is credited as being one of the “leading die casters in the United States” and heading a company (identified later as Lester-Phoenix) which “…builds die casting machines and different types of plastic moulding machines.” Paul Orban, the second engineer hired by Lester Engineering (and later chief engineer) said that “He was a pleasant man to work with, a chain smoker, and he paced like a lion in a cage in the engineering department. He was cordial and honest. Nathan was originally a tool-and-die maker. He worked for Reed before starting his own company.”

Nathan’s son, William Morris Lester, was born in Brooklyn, New York on Jan. 14, 1908. He attended Brooklyn public schools and graduated high school in Worchester, MA in 1904. His father’s business impacted him early; William was still in school when he started designing molds and casting machines. After high school he enrolled in Worcester Polytechnic Institute. He graduated in 1928 with a BS in Mechanical Engineering and extensive background experience in die casting machines and mold design.

Worcester Polytechnic Institute

His first job was Developmental Engineer for Precision Castings Co., Syracuse, NY. After almost three years, his entrepreneurial spirit prompted him to leave in 1930/31. Bill went to his father’s shop, Lester Tool and Die Company, and Bill’s first job was Chief Engineer. Bill did own stock in Lester Tool, but it is unknown if he bought the stock before or after he became an employee. Bill designed molds and die casting machines for Lester, and Reed-Prentice Company manufactured the machines under license. Bill increased the efficiency of mold making through numerous improvements and attachments for tool- room equipment. He received several patents for these innovations in pressure and die casting equipment. Given the early dates (from the 1920) of Nathan’s patents and his leadership in the field, his son certainly learned the practical engineering and the business sides from his father. Bill worked about four years at Lester Tool. As we will see, he was a very fast study.

Bill married Betty Lubarksy of Brooklyn, NY on Sept 2, 1934. In 1935 Bill was invited to participate in the start-up of Commonwealth Plastics Company. The new joint venture was based in Leominster, MA. To earn his equity stake in the business, Bill had to design, build and perfect a commercial plastic injection molding machine in 10 weeks.

To put this task in perspective, the only machines that existed at this time were:

None of these machines could meet the cycle time or precision for modern mass production since they were hand operated or of low capacity. Given his education and background, Bill was the man to get the job done.

The deadline was made. The ‘Lester Machine,’ the first modern injection molding device, was born. Melted plastic was injected with thousands of pounds of hydraulic pressure into engraved metal blocks joined together like a closed waffle maker. The machine had a capacity of 4 ounces. The Lester machine did the same work as existing machines, but better and in only 6 seconds. Larger injection molding machines were already being used (primarily to mold rubber) but they took several minutes to create a finished part.

Controversy

There is a debate about the origins of the Lester Machine. It started with an article written for the New York Times by Jennifer Bayot on March 16, 2005. It opened with: “William M. Lester, who revolutionized the plastics industry 70 years ago with his design for an automatic molding machine, died on Saturday at his home in Delray Beach, Fla. He was 97.”

This article prompted one dated May 31, 2005 from “Industry Watch.” In this piece, Don Lewis, formerly a salesman for Lester (and eventually the president) states “Nathan Lester started the company and, as far as the injection machine design goes, Bill had nothing to do with it. He may have sold machines for his father, but his father was the brains behind Lester.” Bill Jaeckel was also a salesman for Lester and later for Reed. He states “Nathan Lester started it all. Nathan was the heartbeat of Lester Engineering.” Mr. Orban states ” “Bill helped his father, though I’m not sure to what extent. His daughter, Mae, helped, too. She worked at the drawing board. But Nathan was its originator.” The article’s author (who is not named) sums up his (or her) reaction to the NYT article:

“…it… says he (Bill) ‘designed, developed, and constructed first full automatic injection molding machines.’ That may have something to do with the mainstream media’s confusion. John Kretzschmar, chairman of the Plastics Academy, offers his opinion. ‘The reporter I spoke with had no clue of the industry and knew even less about what injection molding is all about,’ he says. ‘I know [Bill’s] dad was with him in the company, but I honestly don’t know who invented the Lester machine.’ The former officials, employees, and customers of Lester Engineering say they do.

So should Bill be stripped of all credit for designing the first modern injection molding machine and revolutionizing the plastics industry?

Fortunately, we don’t have to rely solely on the “Industry Watch” article. It was freely acknowledged in 1945 in the book “The Story of New Jersey” that Bill had a significant if not key role in the first injection molding machine and factory:

In 1935 William M. Lester started the first injection molding plant in Leominster, Massachusetts, for the Commonwealth Plastics Company, and he became the designer of the first commercially used machine for injection molding operations.

It is worth noting that this information pre-dates the NYT article by well over 50 years and was never disputed until the 2005 obituary.

Furthermore Bill was inducted into the Plastics Hall of Fame in 1986. I seriously doubt that a man with no technical ability or industry leadership would have been elevated as such. Clearly Bill’s peers thought that he should receive some form of credit and it was provided to him. At that time there plenty of people still alive who remembered when the plastics industry was born. Yet again there was no controversy.

No one is debating that Nathan Lester was a brilliant man, the founder and heartbeat of Lester Tool. But to state that his son Bill only “…may have sold machines for his father” is at best a curious statement. No available history agrees with that. If Bill was simply a salesman masquerading as an engineer, he would have failed when he struck out on his own. But he succeeded. From numerous sources we know that Bill Lester created important designs like cam core pulls, wedge blocks, and rack-and-pinion core operations. He was the founder and GM of two custom molding firms and holds original patents on tamper-proof packaging designs. But even well before those accomplishments, his large number of patents attest to his engineering prowess. Here, for example is one of Bill’s patents dated submitted in 1935 -US Patent 2112342 for a Pressure Casting Machine. And there are more and older patents.

No one is debating that Commonwealth Plastics was the first viable injection molded shop, courtesy of the Lester Machine. It is no exaggeration to say that it revolutionized the plastics industry. So who really built and designed the Lester Machine?

Was Bill capable of building the Lester Machine? No one could argue that Bill made it in his kitchen or basement; the only logical place to make it would be at Lester Tool, where Bill owned stock. Mr. Orban’s account strongly supports a family effort.

Was Bill capable of designing the machine? At this point in his career he was. On Feb 7, 1935, William M. Lester filed for a patent for Pressure Casting Machine (metal). The patent was granted with Bill as the inventor. He has similar patents dating back to 1931 and earlier. From the records, Bill was an accomplished engineer.

Would he get help from his father? Bill and Nathan had a history of cooperation on major machines. For example, they are listed as “Inventors William M Lester, Lester Nathan” for US Patent #US2112343A for a Pressure Casting Machine. They owned a business together. Bill’s father was a nationally-recognized expert in die casting and held numerous patents on casting machines and more. Bill studied under him, designed machines and owned a business with his father. Even Mr. Orban states that “Bill helped his father, though I’m not sure to what extent. His daughter, May, helped, too.” Clearly there was a great deal of cooperation.

Was it a cooperative venture? Clearly it was. Nathan was an incredible businessman and Bill proved to be one as well; if the machine worked, the company they owned would build and market the Lester Machine. There was certainly no animosity over the machine or the results. It was quickly integrated into the family business. This is reminiscent of Nathan’s past employment with Reed. When he had his own companies, he had Reed build his designs under license!

It is safe to say that Nathan was deeply involved in the design of the Lester Machine and Lester Tool probably manufactured it. How else would Nathan, Bill and sister May be working it together, as the only eye-witness recounts? No one had more experience or creativity than Nathan, and Bill, as chief engineer, was also clearly qualified and experienced. Furthermore, Bill’s equity stake in Commonwealth was on the line.

We will never know the exact contribution that each man made. Both were very dynamic individuals. Given their business relationship, it is impossible that the Lester Machine was not a team effort. Credit belongs to both great men. Modern technology is not formed in a vacuum; it is the aggregate knowledge of the past coupled with our current drive for improvement.

Expansion

As soon as the machine was practical, Nathan began producing the new machine at Lester-Phoenix. Commonwealth also sold this machine across the country. Very shortly, international companies heard of this innovation and got on the bandwagon. Father and son got it right the first time – even today, injection molding is one of only two primary ways of making plastic parts or products. (The other method is extrusion, which is primarily used for large items.)

Jumpin’ Jiminy Lapel Pin from Commonwealth Plastics

With the Lester Machine available, plastic materials technology began to expand. It is important to note that before the Lester Machine, very few things were ever made of plastic. John Kretzschmar, chairman of the Plastics Academy said it best:

“It just started an immense industry. There are your car parts, your appliances, your pens, your snow shovels. You know, combs used to be made of deer horn.”

1940s Engle Plastic Hand Press and Late 1940s Negri-Bossi Injection Molding Machine

Pyro Plastics Corporation

Bill was anxious to show the world what could be done with the new plastics industry. In 1939, with war already underway in Europe, he founded his own molding company, Pyro Plastics with his first wife, Betty (who died in 1993). Bill chose the name ‘Pyro’ because he wanted a short, catchy name that reflected the heat of the injection molding process. Pyro’s first location was No. 526 North Avenue East in Westfield (Union), NJ. Initially there were 50 employees. Pyro quickly became a leading contractor of custom made parts and products in plastic. During the war, Pyro, like everyone else, made parts for the defense effort. Some of these included aircraft parts, such as ventilator tubes and nozzles for P-47 Thunderbolts.

Pyro Trade Magazine Advertisements, Dec 1943 and January 1944 (click to enlarge)

In 1945 Pyro eagerly moved into post-war civil production. The entire range of products is too great to list so I will name just a few.

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