Lee's Mills Steamboat Meet

[steamer]

Had a great time at the meet, and had my batteries charged a bit.

Saw this honey of a launch engine.....You'll be in love with this one Jo.

Herreshoff..2.5 x 5 with slip eccentric....all bronze.

[b.lindsey]

Lovely engine Dave, not sure it has enough studs for Jo though 

Bill

[steamer]

She'll overlook it....LOL

[steamer]

Bonus points for the those who figure out the slip eccentric design.......very slick....and simple

Dave

[Maryak]

Turn the handwheel roughly 90⁰

Simple yes, clever yes, not my idea of safe with that handwheel flanging around near your feet, hands or any overhanging body parts.

IMHO the engine needs to be stopped before going near it for reversing. On a good day watch where you step, on a not so good day OH $H1T.

Best Regards
Bob

[steamer]

Yes ...that is the function of a slip eccentric, but this one is different.   The eccentric is integral with a bushing just behind it that surrounds the crank journal and who's OD is the crank journal.  The outside cheek of the crank has a pin sticking out which engages with a flange mounted to the eccentric bushing.   This times the eccentric position.    As the engine is a D valve, the valve is near impossible to throw until the engine is stopped.   Once stopped, the hand wheel is turned in the direction of desired travel and the crank turns inside the eccentric bushing until the pin makes contact with the flange, Then you just open the throttle, and as long as your not right on dead center, it will start up...otherwise give the wheel a bump with your foot and off she'll go.   Kind of an ingenious implementation of the design.

Typical of the Herreshoff design, everything is as big as it needs to be, and no bigger.  He did have a knack for making pretty engines.    But I hear you regarding safety Bob, Ol Nat lost his engineering license because he caused a boiler explosion on a boat trying to get more performance out of it....a long story.....after that he built America's Cup boats.

This engine is from about 1875 or so.

Dave

[steamer]

The crank pin is hollow, the wristpin is hollow, and the casting is about 3/16" thick maximum.   Even the eccentric has got lightening holes in it.   He had some good pattern and foundry people working for him!

Dave

[steamer]

You'll also notice the valve stem guide is a simple lever?....no linear guide, so the end of the stem flexes through an arc.....this design is FAR easier to keep in good working order than a linear guide....easier to make too!
When is wears, you bush the hole down and your done.    The engine turns over VERY  smooth.    It would appear that the mains are grease cups, while the big end bearing is oiled.    The ports are very large for an engine this size also....typical of the brand.

Dave

[Johnlanark]

Beautiful engine. I am building a replica of a slightly later version, which has Stephenson's link reversing and a hotwell with air pump. A long term project. Regards, John, a lurker and admirer of the skills on the forum

[steamer]

Nice looking engine John....I think I know you over at the Steamboating Forum.....I'm "Mcandrew1894" there .....


Dave