(Click on photo for larger image.)
Jerry Kieffer is not a lifelong machinist. He has developed his skills in many areas simply because he was not satisfied with the work of others and felt he could do the job better himself. He has applied his skills to watch repair, gun repair, clock making and model engine construction to name just a few. The project that first brought him to our attention was a 1/30 scale Corliss steam engine model. The tiny bolt shown above was a 1/30 scale version of a 1/4-20 bolt used as an actual fastener on the model. Jerry developed a system of taps and dies to produce these tiny fasteners so that the model would be completely scale down to the smallest detail. He was making the model because he had been told by others that a running engine could not be made completely to scale at that small size. One of the long-term projects he is now working on is a running model of a 1947 Harley Davidson "knucklehead" motorcycle. Not only must it run like the full size version, Jerry is hoping to be able to have it sound like the real thing too.
Many of the projects Jerry takes on are driven by a challenge, either from himself or from a friend, and this was no exception. The following magazine article details the project and also gives a good insight into what makes Jerry tick and how he goes about tackling a project.
The tiny bolt and wrench shown above where what first brought Jerry's skills to the attention of Joe Martin. The ladies wristwatch on the right gives you some idea how much smaller this bolt is than the smallest existing bolts that can be purchased for watches. The following magazine article will tell you a lot about Jerry and how he works. The 1/30 scale 1/4-20 bolt is about .009" in diameter with threads .0005" deep and has a hex nut that threads on.
A detail at the left shows part of the valve mechanism of Jerry's operating 1/30th Corliss engine. At the bottom, a portion of a U.S. 25-cent coin can be seen to give scale. The "dashpots" at the bottom actually pull a vacuum like on the real engine rather than being actuated by hidden springs as on most models of this engine. Tiny handles and other details are perfect, even under strong magnification. (Click on either photo for larger image.)
It seemed like a fairly straightforward project when he started. Jerry Kieffer of DeForest, Wisconsin wanted to build a model of a Corliss steam engine, he wanted to make it inn a smaller scale than usually attempted and he wanted no compromises when it came to scale. He saw the engine he wanted too model in a steam show in Sussex, Wisconsin, so he could get all the dimensions and pictures he needed from the original. The flywheel was ten feet in diameter, and he had a piece of 4-inch thinwall tubing from a truck driveshaft in his shop that would be just the right size if he worked in 1/30th scale. He had done some watch repair and had a selection of the smallest bolts, nuts and screws commercially available, so he figured when he got to the smallest parts, he would use those as fasteners. He had never liked other models he had seen where the builder compromised on the scale by using larger, no-scale bolts and pipes to represent the smallest parts. He wanted a running engine with everything to scale.
Though he had no formal training in machining and only about eight years experience as a hobbyist, he was always good with tools and enjoyed working on very small projects. He built the flywheel first and then parts of the cylinder. Working his way down from the larger to the smaller parts. By the time he had about a year and a half in the model and had told several friends of his project, he found that the smallest screws from a tiny lady's wristwatch were still going to be much too large. There were twice the size of a regulator shaft he needed to cross drill and bolt at a pivot joint. Rather than give up on the project or compromise on the scale of the smallest parts, he began to work on ways to make smaller and smaller bolts. The smallest bolts on the real engine were 1/4-wo size, which scaled out to a bolt smaller than ten thousandths of an inch in diameter with hundreds of threads per inch at 1/30th scale! There was nowhere to go for advice on making threaded parts that small, as his friends in the hobby told him working bolts that small couldn't be made.
After many efforts at trial and error and "just playing with things until they work", Jerry developed techniques of making extremely small taps and dies the size and thread count he needed. From these he could make tiny hex head nuts and bolts. There were no shortcuts, and many taps would be broken to make a single die, but once he had a die, making the little bolts was relatively easy. In fact, if you ask him if it is hard making bolts that small, he'll tell you, "Making them is easy. It was figuring out how to make them that was hard."
When drilling holes in a steam chest that will eventually receive a number of these tiny bolts, it is not uncommon to break off a tap in one of the drilled holes. When this happens, Jerry throws away the part and starts over. When asked why he doesn't just drill out the broken tap with an oversize hole, fill it with a dowel pin and re-drill rather than scrapping the part, Jerry replied, "Because someday, somebody is going to take this thing apart and they'll know I screwed up." He simply refuses to compromise his goals for perfection at any level...even if it will probably never be seen by anyone else. He would know the mistake was there, and that is enough to make him redo the entire part until it is perfect. Jerry goes on to say, "Most people are willing to do about 90% of the work on a project and then say, 'That's good enough'. I guess my motto would be 'Good enough just isn't good enough'".
Each handwheel, lever and fitting is a miniature reproduction of the exact shapes of the original, and each presented its own problems and resulting solutions. Some details are not even seen once the parts are assembled, but they're there. For example, the model needed a very small, hollow oil line. Jerry finally located a company that manufactured hypodermic syringes and purchased some of the very fine, hollow tubing used to make the smallest needles. He bent that to shape and made tiny compression fittings for each end so that the oil line is functional. Just looking at it, there is no way to tell it is not just a piece of wire, but it is hollow and it does work, and Jerry knows that when he looks at his model.
The real Corliss engine uses vacuum dashpots to retract part of the valve gear. On virtually every model of this type of engine, the modeler hides a spring inside the housing that acutally retracts the rods, as no one looking at it can tell the difference. On Jerry's model, however, the dashpots actually pull a vacuum to retract the rods...another example of his total devotion to realism.
Jerry lubricates the system with a few drops of light oil and attaches a tube from a small electric aquarium air pump to the input pipe, gives the flywheel a gentle push and the little engine springs to life. Delicate adjustment with the tip of a finger on the regulating handwheel of only a few degrees produces an instant change in speed. It operates smoothly and almost soundlessly as low as just 3 RPM! The tiny "banjo oiler" on the main bearing seems to hang suspended in space as the shaft rotates around it. The rods and valves circulate in an intricate motion as the cylinder pumps back and forth. It runs as perfectly as it looks. This model has made believers out of a number of "experts" who told Jerry it was impossible to maintain scale sizes down to this level and still have an engine that works.
To complete the challenge to himself, Jerry made the Corliss engine using a Sherline Model 4000 miniature lathe and Sherline Model 5000 vertical milling machine that only cost about $500 each. This should be encouraging to those who think that you need both years of experience as a machinist and a big shop full of large and expensive machine tools to do good work.
Here is a close-up of the blacksmith's triphammer Jerry is holding in the photo at the right. No castings were used, and the model remains unpainted to show that no mistakes were covered up or fillers used. The look of cast parts was achieved by bead blasting the finish. Some of the parts were made from several pieces silver soldered together. (Click on either photo for a larger image.)
For his work on this and other models he has completed, Jerry was recently awarded the honor of "Metalworking Craftsman of the Year" by the Joe Martin Foundation for Exceptional Craftsmanship. This annual award goes to craftsmen in various fields of miniature machining and is accompanied by a check for $1000. Jerry is a marketing representative for a Wisconsin utility company and has only been working with machine tools in his spare time for about eight years, which makes his accomplishments all the more impressive. Prior to this recognition, Jerry says the only thing he had won was "a quart of oil for an entry at a county fair". Jerry's current work illustrates that some of the most interesting projects can be found at the small end of the size scale and require little more than time and the determination to do a really good job.
© 2003, The Joe Martin Foundation