Author Topic: Twin Grasshoppers  (Read 7591 times)

Offline Chipmaster

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Twin Grasshoppers
« on: December 14, 2022, 01:02:24 PM »
I was given this part built Twin Grasshopper ten years ago by a friend who bought it about forty years ago from someone who worked at Reeves when the shop was at Marston Green Birmingham, we assume they used to sell the Grasshopper castings. The model is a pair of engines fastened onto a 1/8”thick steel plate sharing a long crankshaft. I machined the brass flywheel at the time otherwise the pictures below show the engine as received.
All the castings were present except for one of the four rocker shaft brackets. Luckily a fellow member of the Black Country Live Steamers BCLS used one of the brackets as a pattern and cast another plus three spares all in brass.

DSC04064 by Andy, on Flickr

DSC04066 by Andy, on Flickr

Twin Grasshopper Beam Engine bedplates and crankshaft. by Andy, on Flickr

DSC04074 by Andy, on Flickr

The castings of one engine are bronze and the other is all brass. It’s going to be rather heavy when it’s finished, the model is pretty heavy at this stage.

The drawings were in a very poor state but fortunately they identified the model,
Grasshopper Engine
by Sydney Owen
Model Engineer 1966

I bought a reprint of the article from the Model Engineer Magazine in the form of a series of .pdf downloads.

Grasshopper Article page 1 by Andy, on Flickr

At that time ten years ago I had a few model engine builds in progress and did no work on the Grasshoppers until last month November 22. Prompted by watching three YouTube videos by Keith Appleton in which he restores an identical single Grasshopper model engine.


<a href="https://www.youtube.com/watch?v=L5YSFJAY3jU" target="_blank">http://www.youtube.com/watch?v=L5YSFJAY3jU</a>
<a href="https://www.youtube.com/watch?v=GC0hWn6K1R8" target="_blank">http://www.youtube.com/watch?v=GC0hWn6K1R8</a>
<a href="https://www.youtube.com/watch?v=zCpjmXo4wMM" target="_blank">http://www.youtube.com/watch?v=zCpjmXo4wMM</a>

Links to be added when possible


The condition of the drawings that came with my model was so bad that I have ordered a set from Sarik Hobbies, they’re in the post at the moment. I can’t read some of the critical details in the Model Engineer Magazine reprints because the resolution wasn’t high enough.

Here are the rest of the castings

Twin Grasshopper Beam Engine by Andy, on Flickr

There are a few extras or spares such as two extra water pump castings, and a Stuart Steam Hammer cylinder casting on the left that has been misfiled.

Andy


« Last Edit: December 14, 2022, 04:44:32 PM by Chipmaster »

Offline Michael S.

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Re: Twin Grasshoppers
« Reply #1 on: December 14, 2022, 01:34:18 PM »
Hi Andy, that looks very interesting. And certainly very rarely seen as a twin.
I find it very interesting to take over old projects and learn the history of these model steam engines with a lot of research.

Michael

Offline Chipmaster

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Re: Twin Grasshoppers
« Reply #2 on: December 14, 2022, 02:41:03 PM »
Hi Michael, I'm not aware of any other twin grasshoppers.
I had considered whether the idea made sense and should I complete them as separate engines. As the model is simply a pair of left and right handed engines it should be easy to separate them if necessary. At the moment the crankshaft bearings are perfectly in line, the crankshaft is dead straight and rotates freely. As built the cranks are 180 degrees apart, I can't work out how they were assembled, there's no pins or evidence of solder so I'll leave them alone and see how it runs. The crankshaft could be  sawn in half then connected with a coupling between the engines that would enable them to be set 90 degrees apart for easy starting.   
Andy

Offline vtsteam

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Re: Twin Grasshoppers
« Reply #3 on: December 14, 2022, 03:55:59 PM »
Very interesting and impressive engine!  :ThumbsUp:  :ThumbsUp: :ThumbsUp:

I look forward to seeing what you do with it.  :popcorn: :popcorn:

(I'm also very curious about the horizontal milling attachment shown on Mr. Owen's lathe in the lower left photo on the ME page.)
Steve

Offline Chipmaster

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Re: Twin Grasshoppers
« Reply #4 on: December 14, 2022, 04:43:37 PM »
Thanks vtsteam,

I have no knowledge of the attachment and can't improve any further on the image quality unfortunately. 

Andy

Online Jo

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Re: Twin Grasshoppers
« Reply #5 on: December 14, 2022, 05:05:07 PM »
(I'm also very curious about the horizontal milling attachment shown on Mr. Owen's lathe in the lower left photo on the ME page.)

Its a bit of a hotch potch  ::)

Jo
Enjoyment is more important than achievement.

Online Jasonb

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Re: Twin Grasshoppers
« Reply #6 on: December 14, 2022, 05:12:20 PM »
It's not unlike the "globe" milling attachments

http://www.lathes.co.uk/globe/

The engine is not unlike the one Canadian Model Engineering do

https://www.cmodele.com/SteamEngines.html

And one from what looks like iron castings on Station Road steam

https://www.stationroadsteam.com/easton--amos-grasshopper-beam-engine-stock-code-6829/
« Last Edit: December 14, 2022, 05:18:22 PM by Jasonb »

Offline Chipmaster

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Re: Twin Grasshoppers
« Reply #7 on: December 14, 2022, 05:35:43 PM »
Yes the tenons or slots seem unnecessary to me, they've also been machined in the beds of my engine.

Andy


Offline Chipmaster

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Re: Twin Grasshoppers
« Reply #8 on: December 14, 2022, 05:52:59 PM »
I machined the two pairs of Motion Brackets that fit on top of the cylinders. After marking out and drilling the required holes I bolted the mirrored pairs together and began milling. The castings had two lobes, one side was sawn off after deciding which looked best.

Twin Grasshopper Beam Engine by Andy, on Flickr

Twin Grasshopper Beam Engine by Andy, on Flickr

 Twin Grasshopper Beam Engine by Andy, on Flickr

Twin Grasshopper Beam Engine by Andy, on Flickr

Twin Grasshopper Beam Engine by Andy, on Flickr

Cut off sections no longer required

Twin Grasshopper Beam Engine by Andy, on Flickr

Fitted to the top of a cylinder.
Twin Grasshopper Beam Engine by Andy, on Flickr

Used a Dremel with a burr to get the brackets to clear the cylinder covers.

Twin Grasshopper Beam Engine by Andy, on Flickr

Andy

Offline vtsteam

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Re: Twin Grasshoppers
« Reply #9 on: December 15, 2022, 03:21:32 AM »
Nice job shaping those brackets!  :ThumbsUp: :ThumbsUp: :popcorn:

(thanks Andy, JasonB re lathe attachment... finally realized it reminded me of J A Radford's "elevating heads")
Steve

Online Roger B

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Re: Twin Grasshoppers
« Reply #10 on: December 15, 2022, 11:04:13 AM »
A good start to an interesting project  :ThumbsUp:  :ThumbsUp:  :wine1:
Best regards

Roger

Offline Chipmaster

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Re: Twin Grasshoppers
« Reply #11 on: December 15, 2022, 04:57:25 PM »
Cheers Roger  :ThumbsUp: and I agree with you Jason the grasshopper sold by Canadian Model Engineering is identical but they use different metals for the castings.


The two beam castings cleaned up.

Twin Grasshopper Beam Engine by Andy, on Flickr

Milling the forked end

Flickr Video
Twin Grasshopper Beam Engine by Andy, on Flickr

Flickr video
Twin Grasshopper Beam Engine by Andy, on Flickr

Flickr video
Twin Grasshopper Beam Engine by Andy, on Flickr

Almost done apart from some of the holes need to be opened up.

Twin Grasshopper Beam Engine by Andy, on Flickr

Andy
« Last Edit: December 15, 2022, 05:03:28 PM by Chipmaster »

Offline Chipmaster

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Re: Twin Grasshoppers
« Reply #12 on: December 22, 2022, 09:36:37 PM »
The engine came with two pistons with mild steel piston rods and one of them was fitted with two iron piston rings.

Twin Grasshopper Beam Engine by Andy, on Flickr

I wasn't keen on the iron piston rings running in the bronze and brass cylinders. The rings weren't a good fit in the piston or cylinder and the piston rods would probably rust so I decided to make new pistons. At that stage after I'd ordered 1.1/2" O rings I discovered the engines had been made with a 1. 9/16" bores instead of the 1. 1/2" as per the drawings =  :toilet_claw:

Another pair of brass pistons were machined and grooved to take single silicone rings.

Twin Grasshopper Beam Engine by Andy, on Flickr

Twin Grasshopper Beam Engine by Andy, on Flickr

Twin Grasshopper Beam Engine by Andy, on Flickr

New stainless steel piston rods threaded 1/4 BSF at each end.

Twin Grasshopper Beam Engine by Andy, on Flickr

Twin Grasshopper Beam Engine by Andy, on Flickr

Twin Grasshopper Beam Engine by Andy, on Flickr

Andy

Offline Admiral_dk

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Re: Twin Grasshoppers
« Reply #13 on: December 22, 2022, 10:41:52 PM »
The new Pistons and 'Rings' are probably a Very Good Idea  :ThumbsUp:

They looks good and I'm sure you will be glad you did later  :cheers:

Per

Offline vtsteam

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Re: Twin Grasshoppers
« Reply #14 on: December 23, 2022, 06:48:01 PM »
Great photos, and progress!  :popcorn:  :cheers:
Steve

 

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