Marine Compound Engine

March 2010.

John R. Bentley 2010.

Machining the
-  for the Stuart Compound Launch Engine  -

(Part 2 of the crankshaft assembly page)

The dual eccentrics are each twenty degrees from being directly opposed (total of 120 degrees apart)

Four-jaw chucks were just made for eccentric turning!

Finishing the collar and facing the outer eccentric

Pilot drilling the shaft hole

Centres located 140 degrees apart

Inner eccentric faced-turned

Turning the rim on the outer eccentric

Reversed in the chuck - now ready to turn the inner eccentric rim and face the back side

The basic shape

Drilling out in preparation to reaming to final 5/16" size

I would feel a lot better using undersize reamers on this cast iron - the smaller diameter holes tend to come out plenty large. The gunmetal is the opposite - small reamed holes (and tapped holes) are tight.

Turning a stub mandrel to form the collar exactly concentric with the shaft

Turning on the stub will prevent the collar from appearing to wobble when rotating

Tapping for the grub screws (setscrews)

The screws supplied are plenty long - better than too short

I will either cut them shorter or drill deep dimples in the shaft
when the final position is determined

Compound Launch main page


Castings, Materials and Fastenings


Cylinder Block

Top Cylinder Covers

Lower Cylinder Covers

Steam Chests

Crosshead Guides and Bracket


                 Eccentrics (this page)


Connecting Rods and Crossheads

Main Bearings


Fittings: Oil Cups

Fittings: Drain Cocks

Fittings: Exchange Pipe, Flanges and Glands

Stephenson Link Reversing Gear (5 pages)

Completing and Erecting the Compound Launch Engine


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(c) John R. Bentley 2010.