Joe Martin Foundation "Metalworking Craftsman of the Year" award winner for 1997
Jerry's 1/30 Corliss is accurate down to the smallest bolt. (Click on photo to view a larger image.)
If you haven't already done so, read more about Jerry Kieffer, his background and his quest for total scale in his introductory page. There you will also find links to other model engines, tools and clocks he has made.
Jerry's main introductory page has a pretty complete story of how this model came to be. It started with taking photos and dimensions from the real engine, which is in a museum in Ashland, Wisconsin. Scale was determined by the find of a 4" diameter piece of truck axle that would make the right sized representation of the original's 10' diameter flywheel at 1/30 scale. From there Jerry built the larger pieces, thinking all along that when it came time to getting down to the smallest fasteners he would just use screws from a ladies' wristwatch--the smallest screws he could find. Several years into the project, it became apparent that if he were going to stick to true scale all the way to the smallest parts, the smallest screws he could buy would be grossly out of scale on this model. Rather than compromise and use out of scale fasteners, Jerry decided to make his own. The smallest fasteners on the project--1/4-20 bolts on the real thing--ended up being less than .010" in diameter with threads a half a thousandth of an inch deep. To make the taps and dies to create these tiny fasteners was quite a project in itself.
Jerry brought a nice display with him to the NAMES show in Michigan one year that featured the Corliss and some of his other small parts and tools. This will give a good idea of their small size. (Click on photo to view a larger image.)
With oil lines made from hypodermic needle material with actual scale compression fittings on the neds and scale fasteners throughout, conventional wisdom was that an engine in this small a scale could never be made to actually run. Jerry proved them wrong. Using the pressure from a small aquarium air pump, the engine starts with a light turn of the flywheel and speed is controlled down to a few RPM with the control handwheel. Actual dashpots pull a vacuum rather than resorting to hidden springs as most modelers do.
Here are two photos of the actual Corliss engine Jerry used as a prototype. He made many trips to the antique steam museum in Sussex, Wisconsin where it is on display to take detailed photos and dimensions. (Click on either photo to view a larger image.)
(Click photo for larger image.)
|This model Corliss steam engine is built to 1/30 scale in every detail, down to the smallest bolt. The dashpots pull and actual vacuum (instead of using hidden springs) and even the tiny oil lines are functional. The 4" flywheel represents a 10' diameter one on the real engine, and it started life as part of a truck driveshaft.|
|A closer view reveals the hypodermic syringe material used as oil lines, the handwheel speed control and some of the delicate linkages. A US Quarter illustrates how small some of these parts actually are. A US quarter dollar coin is used for size reference in all photos.|
|The speed control handwheel, the tiny oil lines made from hypodermic needle material, valve linkages and the vacuum dashpots can be seen in this photo.|
|The "banjo" oiler is designed so that it remains vertical as the shaft turns. The counterweight at the bottom keeps it that way. It is an interesting motion to watch and can be better appreciated when actually seeing the engine run.|
|The back side shows a tiny photoengraved name plate with all the original information reproduced in scale. Unless you have extraordinary eyesight, you will need a magnifier to read it.|
|Note the extremely tiny threaded T-handle on the regulator.|
|The tiny bolt on the left is less than .010" in diameter and has a hex head and functional hex nut. Threads are only .0005" deep. If you drop one of these tiny bolts on the carpet, forget it! Jerry developed a way to make a tiny tap, and then using the tap--or rather many of them because they are easily broken--he was able to make threading die. On the right inside the watch bezel is a tiny wrench Jerry created to tighten the nuts. This tiny nut, bolt and wrench are on display in the Craftsmanship Museum in Vista, CA along with some of Jerry's other tiny parts.|
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