Don Bancroft (Left) and Les Zeman (Right)
By The Metric Maven
I grew up in an interesting household, with my mother, an artist, and my father, a technical person. One of my earliest recollections is spending time at my grandfather’s workshop. He had a scale model steam engine that briskly rotated. At other times there was a cat-whisker and crystal used to make a crystal radio. I never knew what might appear on his workbench.
My father worked in a small house-sized dwelling, below a very tall radio antenna. From there he maintained radio traffic, and teletype traffic, at Iowa Police Radio. In the days when long distance telephone was very expensive, it was amazing to hear my father instantaneously talk with Albert Lee Minnesota, or Story City Iowa, with the flip of a switch. He had to type both ends of the radio traffic on a mechanical typewriter–real time. My father worked on one of the first cable television systems in the United States, where he picked up some electronics knowledge. He worked on cars and mechanical equipment, which taught him a lot about mechanical devices.
My father is a very thrifty man. He discovered a television set whose cabinet had been severely damaged in shipment was on sale for a pittance. My father purchased the set, created a mounting bracket inside of a closet that adjoined our living room and mounted the television so it looked much like a flat panel television of today. I knew of no other, and it was really futuristic cool in my single digit years. I liked to look at the orange glow of the television tubes when I looked into the closet. It inspired wonder. When I was asked what I wanted for my birthday, I said I wanted a built-in TV in my bedroom, just like in the living room had. Amazingly, my father found a small television, and mounted it into the wall of my room, again inside an adjoining closet. I fell asleep watching Lassie, and tinkered around as Saturday morning cartoons were displayed above me. My house was the coolest hi-tech house in my small town—In my opinion anyway.
My parents purchased a chemistry set for me, which included two thermometers mounted side-by-side. One had a small reservoir for water, and a wick that lead to the bulb of one thermometer. The other thermometer bulb remained dry. I added water, and on an included set of instructions, it showed me how to compute relative humidity. It was a nerdy thrill when I noted the temperatures were different on each thermometer, and computed the relative humidity. It was almost certainly my first scientific measurement and computation.
My father founded and ran a small offset printing business in conjunction with his other work. Graphic arts would become his lifelong vocation. He learned how to screen print, and then considered printing glassware. One problem was that ink would not stick to glass. My father (and family’s) long time friend Skeez Hartsock had a friend at National Gypsum in Chicago. The friend was a chemist. He tried to mix an experimental white colored epoxy that he thought might stick to glass. It was in the early days of epoxy, probably around 1960. Skeez obtained some of the custom epoxy, and my father experimented with it by printing on some green ice tea glasses for Tomco (a local seed company). It worked reasonably well, but was clearly not dishwasher-safe, and after a few washings, the print would slide off like a decal.
The only way my father could make this business successful was to use ceramic ink, and fire the ink and glassware at about 566 Celsius (1050 Fahrenheit). A lehr is a long continuous “kiln.” One can place glassware on one end of a conveyor belt, it will ramp the glassware up to firing temperature, maintain it for a prescribed length of time, and then cool it down. Commercial Lehrs existed, but they were all way too long to fit in my fathers print shop, and all were fired using natural gas. My father went to local electrical contractor Bud Packard, and Skeez to see if it might be possible to make an electric “fired” Lehr that would be short enough to fit into his building.
Skeez calculated the electric current required to raise a known mass of glass to 566 Celsius, and how long it would take to attain that temperature. The calculation was taken to Bud Packard, who was asked if it would be possible to attain these temperatures using using Calrod type elements. He said it should not be a problem because the Chromalox company had that type of unit available with a sheath temperature of 1093 Celsius (2000 Fahrenheit). It would take about 30 minutes to go from room temperature to the firing temperature. The gas lehr was about 37 meters (120 feet) long. The electric lehr my father, Skeez, and Bud designed was expected to pre-heat, fire, and cool-down in only 12 meters (40 feet). The glass had to cool down slowly enough to anneal, so it would not shatter, and everything seemed achievable, based on preliminary calculations.
Bud and one of his assistants, Roy Green, wrote-up a pre-design to determine how much room, and length of Chromalox element they needed to obtain the desired temperature. There was no existing technical literature about how to design an electric lehr. Another person my father knew, George Samus, contacted an engineer at Bartlet Collins Glass Company to provide some guidance on proper preheat and cool-down times.
Coal Stoker Used to Drive Stainless Steel Conveyor Belt (click to enlarge)
It was determined that a stainless steel conveyor belt would be required to withstand the necessary temperatures. The next obstacle was how to drive the belt along at the required speed. After some thought, Roy Green figured out that using a drive from a coal stoker would have about the right speed ratio needed. As I recall, a coal stoker was located in the Montgomery Ward store next door. Roy Green did the design and built the drive for the conveyor belt.
The lehr was finally ready for testing. Bud suggested to my father, that because the lehr would present such a large load to the three phase power line, they should talk with the power company, and obtain their blessing before they begin testing. My father approached a high ranking employee, named Cecil, from the power company. Bud Packard suggested Cecil come down and inspect the device in-person. He replied that “He didn’t need to come down and look at it, because anything you were going to put on the line, we could handle.”
My Father’s Lehr for Firing Printed Glassware (click to enlarge)
Honeywell Pyrometer for measuring the temperature inside the lehr (click to enlarge)
The following evening testing began. After they achieved a temperature of around 375-425 Celsius (700-800 Fahrenheit), mother nature suddenly informed the designers they had overlooked the expansion of the metal rail along the side of the lehr in the firing zone. The lehr lifted off the floor, and was belching so much smoke from the insulation dust burning off, that Bud (who was fire chief at the time) obtained gas masks from the fire department. The smoke was so thick they had to lay on the floor to observe the test. As the lehr continued to further rise from the floor, they suddenly lost power.
The group went out to the alley to see if Bud could see why power had been interrupted. They discovered the transformers were boiling oil down the power pole. The power company showed up later to replace the fried transformers. The main line for all the businesses on that side of main street including a large grocery store (P&G) were off-line. The power company had to install larger transformers to handle the expected load.
The next morning a power company engineer was quite pissed-off, and paid my father a visit. When my father was confronted about what the lehr had done, he pointed out that his manager stated you could handle “any load we could put on the line” and had approved it. That was the end of that. It also was a clear lesson on the importance of measurement and quantification. The power company manager simply assumed, without any attempt at quantification, there was no load which could overload the transformers. My father, Bud, and Skeez had carefully followed numbers, the representative of the power company could not be bothered with evaluating numbers. My father’s lehr was in operation at Pyrographics until a few years ago.
Bulova Accutron Spaceview Watch
As stated previously, my father also worked as a radioman at Iowa Police Radio. It was the first time I saw a mechanical clock with a digital output. Its display was in 24 hour time. My father was very interested in accurate time pieces, especially watches. In that era, the average person had to make a phone call to an automated phone, which would announce time for setting one’s watch or clock. The gold standard was WWV in the US or CHU Canada. CHU Canada would announce the time in both English and French. One could access each of these stations using a shortwave radio. My father had a friend add a power supply to an amateur radio receiver designed for a car, and gave it to me as a birthday present. I recall letting WWV or CHU act as background sound as I puttered around my room. My father then purchased a Bulova Accutron Spaceview Watch. I thought it was the coolest thing I’d ever seen. I could see all the electric and mechanical design, and this I found fascinating.
I would finally work in the print shop (after my father had sold it). I discovered that it was an operation run on measurement. Offset presses work on the principle that oil and water don’t mix. The water used has a small amount of acid added to it to continuously etch the water receiving areas of a printing plate. The amount of acidity is critical, and one would constantly check to make sure the pH of the water was within operating range. The thickness of plate and “blanket” packing was critical to producing quality images.
My father also supervised screen printing, which he had taught himself when I was a boy. For years the screens had been stretched “by hand.” One needed a tight screen on a frame to produce a sharp image with a measured amount of “off-contact.” In the late 1970s, I recall that metrication was still discussed, and my father purchased the first tension gauge to measure how tight silkscreen material was in its frame. The force was in Newtons over a given metric area. At that point I still had optimism that we might become metric in the US.
I would later attend Engineering School at a nearby university. Each year they had a spring festival where the engineering departments would show the results of serious, and not-so-serious projects. One in particular was to create a device to fire an egg into the air, and have it shatter in the center of a cast-iron skillet perhaps 10-20 meters away. I recall they would get three tries. A number of “contenders” showed up with all manner of serious, and perhaps not-so-serious contraptions. A few contestants came within a few hundred millimeters of the pan.
A pair of Asian students then showed up with a simple spring loaded catapult-like design. They carefully measured the distance from the pan to their “catapult.” The compression length of the spring was then measured with a scale (I could only hope it was metric). My father turned with his hand shielding his face, and whispered to me: “these are the first guys that bothered to measure anything.” I shook my head in complete agreement. The first shot was a bit off. After a quick computation they changed the length of compression. The egg shot up into the blue Iowa sky, and scored a hit, directly centered in the skillet.
I had been encouraged to measure by my father, and as my readers know, I took to it like a duck on an Iowa June bug.
My father passed away on April 29, 2019 or 2019-04-29 10:47 This designation is fitting, as he had changed all his computers and documents to use international date and time, just after he read my blog on the subject in 2014.
If you liked this essay and wish to support the work of The Metric Maven, please visit his Patreon Page.