Author Topic: Twin Oscillators  (Read 5907 times)

Online Jo

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Twin Oscillators
« on: April 11, 2019, 05:35:47 PM »
In the UK there are a number of suppliers of casting sets for Twin Oscillators. In Surus' collection he had acquired a Stuart Twin Oscillator at vast expense :ShakeHead: on my part for him at the midlands Show:



To enable me to have an engine to make this week I managed to purchase a set of Blackgate Castings for their Twin Oscillator:



If you buy these new the Stuart's set works out at 115 and the Blackgate one 62.50, the Blackgate engine is actually bigger than the Stuart one  :)

As expected both sets of castings came with legacy imperialistic drawings  :disappointed: so first they need to be converted into metric. While the drawing that came from Stuarts is very nice and clear the copying of the Blackgates drawing has degraded through poor photocopying (sample of drawing attached) :ShakeHead:

As with all legacy drawings my first job is to part them out into individual part jpegs, clean up the drawing of each part and lay them out on A4 sheets. They can then be printed out and ISO Metric measurements added - I normally do these in red pen. The drawings are then rescanned and individual pages can be printed off to take out into the workshop as required  :wine1:

Jo


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Online Jasonb

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Re: Twin Oscillators
« Reply #1 on: April 11, 2019, 06:30:59 PM »
Jo is the Barstock included in the Blackgates price or have you added that to the photo? Also what material is the flywheel as it does not look like iron or steel?

It's about time you got the little fellow to make some of his own rather than just hoarding them away :)

Online crueby

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Re: Twin Oscillators
« Reply #2 on: April 11, 2019, 06:32:07 PM »
Yeah,. get him a Sherline, he can reach the cranks on those...

Online Jo

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Re: Twin Oscillators
« Reply #3 on: April 11, 2019, 06:36:18 PM »
Both kits come with all of the required bar stock JB. The Blackgates flywheel is BMS, the Stuart's one looks to be disc of brass :thinking:

I think Surus is still a bit young to be let loose on a Lathe  :o

Jo

P.S. He has Little C (ME Cowells) in the same room as his casting collection but has not shown it any interest  ::)
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Online Jasonb

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Re: Twin Oscillators
« Reply #4 on: April 11, 2019, 06:40:22 PM »
That's a good buy then compared with the Stuart.

Online Jo

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Re: Twin Oscillators
« Reply #5 on: April 11, 2019, 08:05:40 PM »
That's the theory but both seem to be having foundry problems at the mo   :(

Jo
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Online Jo

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Re: Twin Oscillators
« Reply #6 on: April 12, 2019, 08:04:32 AM »
Having spent our Thursday evening fondling the two sets of Oscillator castings the main observations are that while the Blackgate's engine is bigger the Stuarts Engine is much neater as it has a built in passages leading to the reversing mechanism and lost wax castings rather than sand castings.


Importantly the Blackgate's drawing does not detail the connecting up of the steam/air pipes. When I visited the Alley Palley show earlier this year I photographed the original Blackgates engine that has all the plumbing and a steam valve but I am not sure if that valve is also a reverser. It must be possible to do something prettier with the plumbing :noidea:

Jo

« Last Edit: May 12, 2019, 09:49:49 PM by Jo »
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Offline Ramon

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Re: Twin Oscillators
« Reply #7 on: April 12, 2019, 08:50:48 AM »
It must be possible to do something prettier with the plumbing :noidea:
Jo


How's this Jo ?  :)


"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Online Jo

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Re: Twin Oscillators
« Reply #8 on: April 12, 2019, 09:17:01 AM »
That's a big improvement Tug  :)

It would be much easier than trying to plug the lines in what I have been playing with.

Jo
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Online Jo

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Re: Twin Oscillators
« Reply #9 on: April 16, 2019, 05:05:50 PM »
A few features of making the Blackgates engine:

Crankshaft - Having chucked the piece of bent bar stock provided for the crankshaft in a suitable storage container it was replaced with a nice piece of straight ground stuff. The balance weight has to be fitted on the end of the shaft then milled to allow the pin to be fitted.

Covers: nice and easy to make and lots of spare metal provided  :)

Cylinders: These castings have suffered with the two haves of the pattern being somewhat out of line and who ever hacksawed them apart doesn't know how to cut square :ShakeHead: Following a bit of filing to get the two haves level the cylinder could be held in a three jaw chuck for boring.

While there is still lots more to do on the cylinders - a pic of the bits of the engine so far.

Jo
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Offline Roger B

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Re: Twin Oscillators
« Reply #10 on: April 16, 2019, 07:37:21 PM »
Good progress  :ThumbsUp:  :ThumbsUp:  :wine1: I hope Surus is happy with it  :)
Best regards

Roger

Online Jo

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Re: Twin Oscillators
« Reply #11 on: April 16, 2019, 08:39:39 PM »
Thanks Roger,

I haven't brought them back in yet as I am planning to get the cylinders completed before he gets his feet on them. In the mean time he is still fondling/guarding the Stuart Casting set, it looks like the stand is getting very shiney ::)

Jo
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Offline K.B.C

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Re: Twin Oscillators
« Reply #12 on: April 16, 2019, 11:34:19 PM »
JO,
You could also make a reversing block like this  which is much neater than Blackgates who have never attempted to make something neater than what they do.

Another thing that I do is to fabricate the cylinders and scrap the ones supplied, I think that they have been copied from existing casting,
You then need only buy the standard.
George.
Your never too old to learn.

Online Jasonb

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Re: Twin Oscillators
« Reply #13 on: April 17, 2019, 07:15:25 AM »
That's a neatly plumbed setup George and I'm sure the shorter pipe runs help with reducing condensate.

However do you really thing that the big eared one will ever let Jo scrap castings :LittleDevil:

Online Jo

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Re: Twin Oscillators
« Reply #14 on: April 17, 2019, 07:45:20 AM »
That is a very neat reversing block George  :)

Why did you scrap the cylinders? Were yours also suffering from out of line pattern parts  :facepalm2:

Jo
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