Author Topic: 1802 Bell Crank Engine  (Read 77829 times)

Offline Jo

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1802 Bell Crank Engine
« on: November 30, 2014, 09:04:30 AM »
This will probably be the earliest engine I will attempt to build, and I was lucky enough to find some details of the original engine:



"The 1802 Bell crank engine is a very compact form of Mr Watt's double rotative engine which was arranged by Mr Murdock and Mr Southern, for steam-engines of small power, to enable them to be placed within a less space than Mr Watt's original construction, and also that they may be set up in any workshop or apartment of a manufacturey, without requiring a particular building for the engine. For this purpose they contrived to support one part of the engine by another"

Anthony Mount designed the model and published it in Engineering in Miniature. I have not seen the original model as Anthony was talked into selling it  :hellno: and later had to make himself a second:



Clearly it was not a very popular model engine as the original casting run was only 10 casting sets and they took nearly 10 years to sell  :shrug:. There has been at least one subsequent casting run but they were unable to get the quality necessary for the Cast Iron components and later ones have bronze flywheels and cam ring  :ShakeHead:. This is one of those original 10 casting sets :whoohoo:



As casting sets go it has lots of challenging parts which could account for so few people wanting to build one. If I say it is unlike any other steam engine I have ever built you will understand why it has been taking up space on my dinning table for a couple of weeks now  :naughty:

Jo
« Last Edit: November 30, 2014, 12:28:35 PM by Jo »
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Offline Jo

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Re: 1802 Bell Crank Engine
« Reply #1 on: November 30, 2014, 10:00:05 AM »
 :headscratch: It is a fascinating little engine to watch run:


As is traditional I will be modifying mine  ;)

Jo
« Last Edit: February 24, 2019, 07:23:51 PM by Jo »
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Offline moerman

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Re: 1802 Bell Crank Engine
« Reply #2 on: November 30, 2014, 10:15:29 AM »
Jo, that is indeed fascinating. Your description makes it sound as if this casting is a rare vintage product. Is it?

Wout

Offline ths

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Re: 1802 Bell Crank Engine
« Reply #3 on: November 30, 2014, 10:38:48 AM »
That is an interesting motion to watch, and I'm glad that tradition will be upheld. So, what are you going to do? Hugh.

Offline Jasonb

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Re: 1802 Bell Crank Engine
« Reply #4 on: November 30, 2014, 10:39:59 AM »
And I though you said this one had gone back into storage :headscratch: good to see it out though.

The castings can still be bought though with the GM parts, not much of a problem as the flywheel is painted and its only the bare edge of the cam ring that would look wrong

Offline Jo

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Re: 1802 Bell Crank Engine
« Reply #5 on: November 30, 2014, 11:30:50 AM »
And I though you said this one had gone back into storage :headscratch: good to see it out though.

It had as the dining table was getting a little busy and I was expecting visitors, still being good but not long now  :LittleDevil:

Jo
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Offline steamer

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Re: 1802 Bell Crank Engine
« Reply #6 on: November 30, 2014, 12:02:29 PM »
Nice!    Can't wait for the build!


Dave

"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline philjoe5

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Re: 1802 Bell Crank Engine
« Reply #7 on: November 30, 2014, 01:38:37 PM »
That's a new engine to me.  In some ways it resembles the James Coombes Table engine with the long connecting rod arms/crosshead guide and crossbar arrangement.  But instead of connecting that to the connecting rod and journal it goes through the bell crank mechanism.  This will be an interesting build and I'll be following along :popcorn:

Cheers,
Phil
If you pick up a starving dog and make him prosperous, he will not bite you. This is the principal difference between a dog and a man.  - Mark Twain

Offline Jasonb

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Re: 1802 Bell Crank Engine
« Reply #8 on: November 30, 2014, 01:44:40 PM »
So Jo will one of your modifications be the correctly shaped cam wheel or will you stay with AM's round one. This would be one advantage to having teh gunmetal casting as you could squash it a bit ;)

Offline b.lindsey

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Re: 1802 Bell Crank Engine
« Reply #9 on: November 30, 2014, 01:48:40 PM »
A very interesting engine for sure. Its nice to know the history of the castings as well.

Bill

Offline Jo

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Re: 1802 Bell Crank Engine
« Reply #10 on: November 30, 2014, 01:54:12 PM »
Hey Guys  8) pleased your are all interested. Jason I am not sure what to do with the cam wheel the instruction for machining it are a bit sketchy and as you say I cannot bend my Cast Iron one.

Now I am not sure if Anthony did what is called poetic license or just got it wrong  :( If you look at the original patent drawing you will see that the bell crank does not have a tail but Anthony's does. The bigger engines like the one in the London Science Museum does have this second power take off on the bell cranks:



But she is a bigger engine and has a very sexy governor  :Love:



Jo
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Online sco

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Re: 1802 Bell Crank Engine
« Reply #11 on: November 30, 2014, 03:12:46 PM »
This is looking a really interesting engine to build Jo - and a proper challenge even for your skills ;-)

Simon.
Ars longa, vita brevis.

Offline arnoldb

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Re: 1802 Bell Crank Engine
« Reply #12 on: November 30, 2014, 03:26:53 PM »
A very interesting engine indeed.  Looking forward to your build Jo  :ThumbsUp:

Kind regards, Arnold
Building an engine takes Patience, Planning, Preparation and Machining.
Procrastination is nearly the same, but it precludes machining.
Thus, an engine will only be built once the procrastination stops and the machining begins!

Offline Jasonb

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Re: 1802 Bell Crank Engine
« Reply #13 on: November 30, 2014, 03:58:58 PM »
But are you making the 1802 one or the 1810 one from the science museum, can't really add sexy features from a later engine. Also how complete is that Science museum engine can't see how the belt to drive the governor would work on that square shaft :ShakeHead:

AM certainly had to make some bits up as he went along with only an etching to go by he would not have had all the details and who is to say the original engraver got it right. There are also the compromises that need to be made to keep the costs of castings down so some detail may have been left off.

J

Offline Jo

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Re: 1802 Bell Crank Engine
« Reply #14 on: November 30, 2014, 04:09:33 PM »
Jason, I don't know how I have confused you  :headscratch: as I said at the beginning I am making this engine:



I am not adding the tails on the bell cranks and I am not adding a governor, they were only fitted to the larger engines. I am going to try to bring her back closer to the design in the original patent for the 4 horses power engine ;)

Jo
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