Author Topic: Stephenson's Rocket  (Read 28597 times)

Offline Craig DeShong

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Re: Stephenson's Rocket
« Reply #180 on: June 22, 2020, 10:55:01 PM »
Excellent!!   :whoohoo:

I’ll agree!  Well done. 
Craig
The destination motivates us toward excellence, the journey entertains us, and along the way we meet so many interesting people.

Offline Brian Rupnow

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Re: Stephenson's Rocket
« Reply #181 on: June 23, 2020, 11:56:31 PM »
Today was a major lurch forward. I started with a 3 1/2" x 12" long piece of aluminum, turned half of it to 3 1/4" diameter, cut it in half, and counterbored both ends to receive the end caps. There is lots of exciting machining yet to come on that main cylindrical body. I had to quit half way thru the day and fabricate some brackets for a new flower box that my daughter was given, then jumped back into the shop to finish the main body so I could make a "mock-up".


Online crueby

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Re: Stephenson's Rocket
« Reply #182 on: June 24, 2020, 12:07:00 AM »
Boiler is taking shape, its a very distinctive shape. On the original, the right side of the firebox was lopsided, so the frame on that side had to be different than the left. So, if a part comes out a little off, you could say it faithful to the original!


 :popcorn:

Offline Brian Rupnow

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Re: Stephenson's Rocket
« Reply #183 on: June 24, 2020, 07:34:54 PM »
I just finished adding the "wood cladding" to my boiler. I used a small (3/16") center drill and set it up to interfere with the boiler o.d.x about 0.020". Set the table stops up on the mill x axis, and rotated the rotary table 19 degrees between each linear cut. It turned out nice.

Online crueby

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Re: Stephenson's Rocket
« Reply #184 on: June 24, 2020, 08:51:37 PM »
Nice trick, gotta remember that one!

Offline Brian Rupnow

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Re: Stephenson's Rocket
« Reply #185 on: June 25, 2020, 12:18:16 AM »
This afternoon I put in locating counterbores and #10 threads in the "boiler" to accept the steam dome and the safety valve. I never knew until this afternoon how badly I sucked at freehanding a "dome". It turned out okay, but the finished result does not reflect the first two attempts. I am not tearing down the set-up on the mill, because the slots for the axles and pivot rods still have to be machined.

Offline Brian Rupnow

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Re: Stephenson's Rocket
« Reply #186 on: June 25, 2020, 10:52:30 PM »
Today I finished the work on the milling machine, and was able to tear down my set-up. You will see in the picture the end of the motor-mount bar, which runs completely thru the boiler from side to side. I was able to drill and mill the slotted hole thru, but that of course left round ends on the slot. I drove across town and bought a 1/2" square file to make the ends of the slot rectangular. There was a HUGE amount of time required to make those rounded ends rectangular, and I have a new blister in the palm of my hand from filing. The main "boiler" is almost finished. The motor mount bar will be held in place by bolts which are hidden by the end cap on the boiler. My initial thought were to Loctite the boiler endplates in place, but I have figured out how to use a "thru-bolt" that is hidden inside the firebox and goes completely thru the boiler and is threaded into the endplate which sets at the front of the boiler. Tomorrow I will make the bracket which supports the rear axle and the pivot shaft for the eccentrics. Then it will be time to start transferring the engines from the test stand over to the actual chassis. The wheels will be left as the last thing to do.

Offline Brian Rupnow

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Re: Stephenson's Rocket
« Reply #187 on: June 26, 2020, 09:11:22 PM »
I'm finished with the chassis of the Rocket, to the point where I have to start transferring engine parts from the test stand over to the Rocket. I ended up having to put rubber o-rings on both pistons. The machine is setting beside me as I type this, running on 10 psi. It still doesn't want to self start, and it should. May be a matter of how I have the timing set, or may be there is still some friction in the system that it has to work thru. It's getting rather exciting now. Tomorrow should see the engines moved, and then I have to start on those big drive wheels.

Offline Brian Rupnow

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Re: Stephenson's Rocket
« Reply #188 on: June 26, 2020, 09:49:44 PM »
Okay, we're good now. After running the engine for half an hour, it self starts. A bit of explanation---I'm not using Viton rings, just plain old rubber Buna-N o-rings. These rings are fine because there are no high temperatures to contend with.--But---they have an amazing amount of "stiction" when first used in an engine. If you give the engine a few drops of oil in the cylinder and run it for half an hour, the "stiction" from the ring goes away. There was enough air getting past the un-ringed piston to prevent the engine from self starting. Now, with rings on both pistons and half an hour run time, there is no residual "stiction" and the engines self start fine. The crank throws are 90 degrees out of phase.

Online crueby

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Re: Stephenson's Rocket
« Reply #189 on: June 26, 2020, 10:15:23 PM »
Terrific, this is coming along great!   :ThumbsUp:

Offline stevehuckss396

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Re: Stephenson's Rocket
« Reply #190 on: June 26, 2020, 10:26:27 PM »
But where is the pictures or video???
Do not be like the cat who wanted a fish but was afraid to get his paws wet.

Offline Brian Rupnow

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Re: Stephenson's Rocket
« Reply #191 on: June 26, 2020, 11:05:36 PM »
The video I posted earlier of the engines running won't change any---Just the engines will be running slower. This is the threaded rod that holds all of the chassis together. It passes thru a clearance hole in the firebox and the rear "cap", thru a clearance hole in the "boiler" and threads into the front cap and smokestack mount. It will get shortened up and the nut will be hidden inside the fire-box. The next picture I post will be with all of the engine parts in place on the chassis.

Online crueby

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Re: Stephenson's Rocket
« Reply #192 on: June 26, 2020, 11:17:12 PM »
The threaded rod is sorta accurate, the real one had a number of rods inside to keep the endcaps from bulging. During testing they added more as they figured out how many were needed.

Offline Brian Rupnow

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Re: Stephenson's Rocket
« Reply #193 on: June 26, 2020, 11:20:53 PM »
That just shows you that "Great minds think alike"----or----"Fools never differ."

Offline Brian Rupnow

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Re: Stephenson's Rocket
« Reply #194 on: June 27, 2020, 03:54:26 PM »
Oh Wow---If I just had some wheels, I could almost go for a drive!! All of the engine parts bolted right up where they were supposed to go. I have a few simple cosmetic detail to figure out, but I'm happy with the way this is looking.

 

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