Author Topic: Oscillating Engine Pivot Speculation  (Read 3221 times)

Offline Jasonb

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Oscillating Engine Pivot Speculation
« on: December 18, 2017, 04:12:18 PM »
Would anyone care to speculate how the cylinder pivot in the foreground is constructed on this engine?

As I see it there is a finger screw which allows  adjustment of the friction/fit of the opposite port face. This screw is locked by a collar which has its lever hanging vertically. Assume the screw has a point to it that mates with a conical hole in the stub on the side of the cylinder. I don't think there is any spring in the pivot which would allow the port face to lift off in condensate built up.
 
Thanks, J.

Offline pgp001

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Re: Oscillating Engine Pivot Speculation
« Reply #1 on: December 18, 2017, 04:27:49 PM »
Jason

I think your description sounds to be pretty good. Its hard to see how else it could work.

Phil

Offline Gas_mantle

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Re: Oscillating Engine Pivot Speculation
« Reply #2 on: December 18, 2017, 04:35:42 PM »
Given that the supports look reasonably robust I'd have thought if the taper screw is properly adjusted the port face wont lift at realistic operating pressures.

Is it possible there may have been a small spring on the port side pivot ?

What is the engine ? I saw something similar a week or 2 back on ebay - if I can find it I'll post a pic.

Offline Jasonb

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Re: Oscillating Engine Pivot Speculation
« Reply #3 on: December 18, 2017, 05:31:29 PM »
Thanks Phil, that is what I have gone for.

Peter, sometimes it is desirable for the port and cylinder to be able to separate as it will let out condensate much like a slide valve lifting of the port face. A parallel screw into a hole and a spring would have been another option but would have thought a less easily adjusted lock nut would have been used in that case.

The engine is one that Jo took a couple of pics of at the Midlands show, I had fancied doing an oscilator for a while and it court my eye so have drawn it out to use up another of those 24mm O rings that I have, flywheels suit a pair of Stuart No10 size. I had sketched out the rough sizes and being stuck home with a sore back decided to draw it up this afternoon as provided I can stand up it will make a nice little project fir the Christmas hols to run along side the more involved projects. All seems to move as it should on the screen so hopefully it might run.

J

Offline Gas_mantle

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Re: Oscillating Engine Pivot Speculation
« Reply #4 on: December 18, 2017, 05:38:26 PM »
Ah ok I see what you mean.

Heres the ebay engine I mentioned, its a bit different to how I remembered it so I don't think it will be of much use but it does have a few similarities.

https://www.ebay.co.uk/itm/EARLY-ANTIQUE-VINTAGE-CAST-METAL-STATIONARY-STEAM-ENGINE-WHEEL-PISTON-PUMP-MODEL/222757108955?hash=item33dd5bbcdb:g:f9oAAOSwke9aM9lS

Online b.lindsey

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Re: Oscillating Engine Pivot Speculation
« Reply #5 on: December 18, 2017, 05:41:21 PM »
Interesting design Jason, and what you are describing sure sounds like it will work. One to follow through the holidays if you decide to go for it.

Bill

Offline Gas_mantle

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Re: Oscillating Engine Pivot Speculation
« Reply #6 on: December 18, 2017, 05:46:36 PM »
How about making one like this :-


I think it's a great looking engine and has great chuffabilty  :)

Online Jo

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Re: Oscillating Engine Pivot Speculation
« Reply #7 on: December 18, 2017, 06:05:34 PM »
If you had asked I would have shown you the other side  ::)

Jo
« Last Edit: December 18, 2017, 06:08:53 PM by Jo »
Usus est optimum magister

Offline Jasonb

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Re: Oscillating Engine Pivot Speculation
« Reply #8 on: December 18, 2017, 06:11:05 PM »
The E-bay one is not unlike one designed by Muncaster which in his book also uses a pointed screw. Julius has drawn up a version that uses a ball into two connes and a spring but I can't see how the spring would compress to let water out if the ball is making good contact with the cones to keep the cylinder in line.

http://modelengineeringwebsite.com/Muncaster_double_oscillator.html

The one in the video link is not unlike the Coventry that a couple of members have posted about on here.

About the time Jo posted the photo there were a nice pair of cylinders on e-bay that I was tempted to buy that look like they would have suited this design well

https://www.ebay.co.uk/itm/OLD-VTG-Brass-OAK-BOUND-Piston-Cylinder-Spare-Part-for-Toy-Steam-Engine-MODEL/222699211159?hash=item33d9e84997:g:CxEAAOSweM1Z90rn

Thanks for the interest Bill, will see what comes of it.

J

PS Please Miss can I see your the back side ;)

Online Jo

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Re: Oscillating Engine Pivot Speculation
« Reply #9 on: December 18, 2017, 06:15:06 PM »
PS Please Miss can I see your the back side ;)

 :hellno: This is all I will let you see.

Jo
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Offline Jasonb

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Re: Oscillating Engine Pivot Speculation
« Reply #10 on: December 18, 2017, 06:18:34 PM »
Thanks Jo

May have another think about how I did the passages for the steam, I kept them under the cleading but having that larger block would be easier and also give somewhere for the banding to fit, I was going to join it underneath.

The one in the Photo sits a bit lower than mine, I went with a thicker base and slightly taller pivots so heh flywheels clear without having to use the wooden plinth but anyone building could reduce these and use a plinth if they wanted.

Not quite decided on all the materials but will probably go for a built up bronze/brass cylinder and iron pivots despite them showing bronze on the rendering. Bed will be aluminium for ease of machining but could be done in steel or iron.

Offline Gas_mantle

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Re: Oscillating Engine Pivot Speculation
« Reply #11 on: December 18, 2017, 06:21:43 PM »
I do rather like oscillators despite their simplicity.

Sometime ago I posted a few questions in forums and asked the youtube member about the brass engine in the video but cold find nothing about it. I'd quite like to make one sometime in the future if I could find the plans.

Online Jo

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Re: Oscillating Engine Pivot Speculation
« Reply #12 on: December 19, 2017, 08:55:06 AM »
We might have found the original build details  :whoohoo:   

:-X

Jo
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Offline Jasonb

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Re: Oscillating Engine Pivot Speculation
« Reply #13 on: December 19, 2017, 09:22:22 AM »
What will it take to unzip you? Maybe an offer of my metric drawings in nice whole millimeters ;)

Jo do you remember if the engine was on a club stand or the SMEE one? SMEE have another more detailed oscilator that is also on my to do list.

Online Jo

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Re: Oscillating Engine Pivot Speculation
« Reply #14 on: December 19, 2017, 09:54:18 AM »
What will it take to unzip you? Maybe an offer of my metric drawings in nice whole millimeters ;)

The model engine drawing hoarder is still looking for the book it is in  :Doh: but I will (and he might once I have PDF'd them) accept a set of Alibre drawing files then it could be made to look more like the original engine design. I have found the vertical version so it is looking likely to be the right engine ::)

Quote
Jo do you remember if the engine was on a club stand or the SMEE one? SMEE have another more detailed oscillator that is also on my to do list.

It is not a SMEE engine  :hellno: It was exhibited at the Midlands on the Tee publishing stand  :headscratch:

Jo
Usus est optimum magister