JEAN Tips on Building a Scale Wobbler

A 1/2-Inch Bore,1-Inch Stroke Wobbler


| May 2005



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Ed Warren supplied these drawings to assist Gas Engine Magazine readers in building the scale “Jean” engine.

Editor's note: Noted model engine builder Ed Warren created this wobbler engine especially for the readers of Gas Engine Magazine.

Ed loves to design and build models, and what follows is a list of tips Ed has compiled to make building "Jean" fun and easy.

Special thanks go to George Broad, former publisher of Modeltec magazine, who published Ed's book (now out of print), Home Made Steam Engines, Volume 1 - The Wobblers, in 1998. Ed supplied George the computerized drawings shown on the top of the opposite page, which George further refined for their book. Enjoy!

For those of you who don't have a reamer, there is another way to drill and ream a hole to the proper size; drill the hole 1/64-inch smaller and then go back through the hole with the proper size drill. Under most circumstances, when a hole is drilled with the proper size drill, it will drill oversize, making for a sloppy fit.

The bearing brass that goes into the cylinder mount can be held in place with thread locker. I let the bearing protrude a few thousandths of an inch to act as a bearing surface for the flywheel.

Starting with the cylinder mount, very carefully lay out the holes and drill them, being extra careful laying out the port holes in the bottom of the cylinder mount so they can be lined up with those in the base. I use brass for the bushing, and after it is pressed or glued in place, I drill an oil hole through the top part of the steel and down through the bushing. This is not shown in the drawing, but it runs better when oiled.