LTDSE

[Webpage under construction]

LTDSE AKA "Low Temperature Differential Sterling Engine". Built using only a Sherline Mill and Lathe.

Play the video to see the engine in action!

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At one point, I thought about using something like this to drive my telescope mount. Not directly but to drive a generator that would supply electrical power to the mount (sorry about that but I need to make sure that all pages on this site have some astronomical reference ;}  Perhaps a "SteamPunk" telescope application???

Anyway, once finished and adjusted, the engine would begin to run at about a 3 degree F differential.  At 5 degrees f, a steady 60 RPM is maintained. A good hot cup of coffee will cause it to run above 400RPM.

Fabrication of the major assemblies (Click images for higher resolutions):

Truing the hot and cold plates using the Mill as a Lathe

The cold and hot plates (top and bottom) are six inches in diameter but the Sherline lathe can only handle diameters up to about five and a half inches. The Mill was turned into a lathe in order to turn these parts.

 Cutting the spacer. Again a job for the Mill as a lathe

Final sizing and truing of the displacer disk

The headstock was rotated 90 degrees so the tailstock could hold a dremel tool.

Completed Displacer

 Axel and link components:

Bearing assy.

Hub assy

Linkage

The linkage is composed of precision parts smaller than a half inch. I learned alot about how to machine parts this small and have a scrap pile to prove it ;) I think the most satisfying thing was holding tolerances and dimensions smaller than 1/2 ten thousandths of an inch with this equipment.

Completed axle assy

Note this shot shows the original design that used wire drive rods. That was redesigned into the connecting rod configuration seen in the final version. The cap screws hold temporary counterweights for friction reduction tests. A lot of energy (relatively speaking) was lost due to wire flex. The loose links reduced the minimum run temperature differential from about 5 degrees C to about 2 degrees C.

Base

Axle, base, flywheel and top plate test fit

 Finished engine