Author Topic: AOG’s version of the Stuart twin oscillator  (Read 3293 times)

Offline AOG

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AOG’s version of the Stuart twin oscillator
« on: March 04, 2018, 08:47:27 PM »
I’ve been working on a Stuart twin oscillator for a while now and I think it’s time to start another build log.



Unfortunately, family issues have severely limited my shop time so this will not be a quick build. Anyway let’s get started. The first part is the standard casting. I flattened the bottom and drilled some mounting holes.



Then the standard was mounted to a tooling plate to act as a reference surface. The part was set back into the vise and the valve area and shaft bosses were skimmed, drilled and reamed.



Next the horizontal air passages were drilled with the part at 90 degrees from the vertical.



Then the vertical passages were drilled.



The part was placed on angle blocks and the sloped passages were drilled.



At this point I broke a drill bit in one of the passages. After stretching the boundaries of the English language trying to get the tip out, I gave up and ordered a new casting. The rest of this section will based on the new casting. After redoing everything I set up and drilled all of the ports for the cylinders and the valve.



Next I deviated from the drawing by drilling and tapping the casting to directly take the PMR intake and exhaust pipes. Then I plugged all of the necessary holes and filed the plugs flat.



I drilled a hole in the valve handle and painted the standard and handle. While those were drying I started working on the cylinder extrusions . First I squared up and flattened the valve area.



Then I turned each cylinder to length.



I was going to bore the cylinders on the lathe but I realized that it would be easier on the mill because of the flat valve area. So I set it up then step drilled and reamed the cylinders.



The cylinders were drilled for the center pivots and then placed on angle blocks to drill the valve holes.



Next I drilled the four holes to mount the cladding.



All of the holes were tapped which completes the cylinders. I’ll end this with the first family shot.



Till next time.

Tony


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« Last Edit: March 04, 2018, 08:50:51 PM by AOG »

Offline b.lindsey

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Re: AOG’s version of the Stuart twin oscillator
« Reply #1 on: March 05, 2018, 12:13:37 AM »
That's a very nice looking little engine Tony and you are well along on it. Nice to see the various set-ups too.

Bill

Offline Thor

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Re: AOG’s version of the Stuart twin oscillator
« Reply #2 on: March 05, 2018, 05:09:00 AM »
Hi Tony,

 Your twin oscillator is coming along nicely, looking forward to see the finished engine. I made a similar twin oscillator without reversing mechanism based on the Stuart, but with no castings. I just used steel for the standard and managed to drill the steam (air) passages without breaking the small drills, and fabriated the cylinders from some brass pieces. It runs well with a fair amount of torque.

Thor

Offline Jo

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Re: AOG’s version of the Stuart twin oscillator
« Reply #3 on: March 05, 2018, 08:30:30 AM »
I have always loved this little Oscillator, nice to see one being built Tony :)

Jo
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Offline bent

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Re: AOG’s version of the Stuart twin oscillator
« Reply #4 on: March 05, 2018, 07:05:12 PM »
Wobble engines don't usually grab me...but this one looks pretty neat considering.  I like that the cylinders and stand are bronze (thought they were only available in alumin(i)um?).  Following with interest.

Offline AOG

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Re: AOG’s version of the Stuart twin oscillator
« Reply #5 on: March 06, 2018, 07:28:54 PM »
Thanks everyone, hopefully I’ll get some shop time this weekend to make some progress on this build.

Tony

Offline b.lindsey

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Re: AOG’s version of the Stuart twin oscillator
« Reply #6 on: March 06, 2018, 07:32:06 PM »
Tony, were these intended for marine use in scale boats (I know PMR offers a twin oscillator for that purpose though not in casting form), and if so do you have plans to do that or will it be for display only?

Bill

Offline AOG

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Re: AOG’s version of the Stuart twin oscillator
« Reply #7 on: March 06, 2018, 08:09:19 PM »
From what I understand, this engine was originally offered as a completed motor for boats. This particular one will be a display piece when I’m done with it. I get my fun from building them. After they’re running I loose interest and they go on a shelf.

Tony

Offline AOG

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Re: AOG’s version of the Stuart twin oscillator
« Reply #8 on: March 12, 2018, 01:25:09 PM »
I guess it’s time for the next update. I had a good shop session this weekend and I accomplished a lot. The next components made were the upper cylinder covers. I turned the profile and parted off the cover.



Then it was into the mill to drill the mounting holes.



Next was the lower cylinder covers. First I turned the part to shape.



Then I drilled and reamed the cover.



After shaping the reverse side of the cover it was over to the mill to drill for the mounting screws.



With the cylinder covers out of the way I decided to make crankshaft. I was originally going to make a built up crankshaft but Stuart calls for a single piece unit. I decided to go for the single piece version. I can always use the practice in accurately turning long skinny parts. It actually came out well.



After parting off and cleaning up I drilled the piece for the crank pin.



The pin was Locktited into place completing the crankshaft. I still had a little shop time left so I made the flywheel. The end was faced and a decorative groove was cut into the face.



Then the center was drilled and reamed.



The piece was parted off, cleaned up and put in the mill. A hole for the grub screw was drilled and tapped.



I’ll end this with an updated family shot.



Till next time

Tony


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Offline Thor

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Re: AOG’s version of the Stuart twin oscillator
« Reply #9 on: March 12, 2018, 06:23:32 PM »
Hi Tony,

 The cylinder covers and crankshaft are looking good, looking forward to see the finished engine.

Thor

Offline AOG

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Re: AOG’s version of the Stuart twin oscillator
« Reply #10 on: March 23, 2018, 06:04:08 PM »
Time for an update. The next parts made were the pistons. They were turned to shape threaded and parted off.



Then the piston rods were cut to length and threaded 7BA.



While I had the three jaw chuck installed, I turned the spring collars and knurled nuts.



I swapped out the three jaw for the four jaw self centering chuck and turned the lower end of the piston rods round.



The end was drilled and tapped. It was then moved to the mill. Two sides of the stock were milled to dimension and the end was drilled.



Then the offset was milled and the parts were separated from the parent stock.



This completes the machining on this project. I ended up cutting the cladding short so I am going to get some brass strips and remake the cladding pieces. In any case I will end with a final family shot.



I still need to make a base, the cladding and fit it all together. Final pics will be in the showcase.

Till next time

Tony


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Offline b.lindsey

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Re: AOG’s version of the Stuart twin oscillator
« Reply #11 on: March 23, 2018, 10:56:12 PM »
Looking forward to it Tony. All the parts look great on their own.

Bill

Offline Thor

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Re: AOG’s version of the Stuart twin oscillator
« Reply #12 on: March 24, 2018, 05:28:26 AM »
Hi Tony,

 You have nearly finished the engine, looking good so far.

Thor

Offline AOG

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Re: AOG’s version of the Stuart twin oscillator
« Reply #13 on: April 15, 2018, 01:24:42 AM »
It’s done and it’s a runner. Pics and a video here:

http://www.modelenginemaker.com/index.php/topic,8037.msg171421/topicseen.html#new

Till next time

Tony

 

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