Author Topic: Stephenson's Rocket  (Read 28562 times)

Offline Brian Rupnow

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Re: Stephenson's Rocket
« Reply #75 on: May 16, 2020, 11:19:36 PM »
I'm getting close to making a start on the Stephenson's Rocket cylinders. I went to my metal suppliers this week and bought a 12" length of 1 1/4" square brass. This will give me enough material to make two cylinders and two steam chests.---and maybe 4 cylinder end caps but I'm not sure yet. There's going to be a bit of finagling, because this brass is 1 3/4" across the diagonals and the bore in my lathe spindle is only 1 1/2". I don't want to waste any of the brass, because that 12" length cost me $50. I will probably hold one end in my four jaw chuck and use a live center to support the outboard end. I can turn the outboard ends of both cylinders in one set up, but I can't bore the cylinders in the same set up, so I"ll have to think more about this.

Offline Jasonb

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Re: Stephenson's Rocket
« Reply #76 on: May 17, 2020, 07:41:01 AM »
Can't you just saw off a piece just over length and then hold in the 4-jaw to face the end, turn OD of one end and also bore all at the same setting then just turn it around to do the non piston rod end which is not so critical?

This cylinder is a bit longer and larger diameter but easy enough to hold though I used a soldered on port face so turned more of the OD



And this one is only 3/16" shorter


Offline Brian Rupnow

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Re: Stephenson's Rocket
« Reply #77 on: May 17, 2020, 03:10:01 PM »
Maybe, Jason. My original idea was to turn both cylinders and four end-caps in one set-up, but I may have to rethink that.---Brian

Offline Brian Rupnow

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Re: Stephenson's Rocket
« Reply #78 on: May 18, 2020, 05:00:42 PM »
Now---If I've done this right, there should be two identical cylinders in there. It is set up so that each cylinder, when sawed from the square stock should be the right diameter and have a 1" long "spigot" attached to one end of each cylinder, to mount it in the three jaw chuck for boring. After the cylinder has been bored, the 1" stub length will be cut off and turned to give me four cylinder end caps.

Offline crueby

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Re: Stephenson's Rocket
« Reply #79 on: May 18, 2020, 06:08:38 PM »
Nice gang turning - this is going to be a fun project for us to watch along with!
 :popcornsmall: :popcorn: :popcorn: :popcorn:   (me and the elves)

Offline Brian Rupnow

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Re: Stephenson's Rocket
« Reply #80 on: May 18, 2020, 07:56:24 PM »
And now you know how I spent my Monday. Everything went very well, no drama. There is more machining yet to be done on the cylinder bodies, but not today.

Offline Mike Bondarczuk

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Re: Stephenson's Rocket
« Reply #81 on: May 18, 2020, 10:33:34 PM »
Hi Brian,

Very smart and a novel approach to a common problem with stock material builds.

I watch your progress on your previous engines and am amazed at your speed and ingenuity.

Mike
"Everything I can't find is in a totally secure place"

Offline Brian Rupnow

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Re: Stephenson's Rocket
« Reply #82 on: May 18, 2020, 11:03:17 PM »
Thanks Mike--I generally take a couple of weeks between builds, but with this damned virus there is absolutely nothing else to do.

Offline Art K

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Re: Stephenson's Rocket
« Reply #83 on: May 19, 2020, 12:14:41 AM »
Brian,
I like your creative lathe dog. Looks great so far.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline Craig DeShong

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Re: Stephenson's Rocket
« Reply #84 on: May 19, 2020, 02:04:52 AM »
Following along Brian  :popcorn: :popcorn:

Thanks Mike--I generally take a couple of weeks between builds, but with this damned virus there is absolutely nothing else to do.

I’m with you there, I’m not looking forward to finishing the Witte, I’ll need another project or I will go stark-raving-mad  :o

And actually, I may have a doozy in the works!

Craig
The destination motivates us toward excellence, the journey entertains us, and along the way we meet so many interesting people.

Offline crueby

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Re: Stephenson's Rocket
« Reply #85 on: May 19, 2020, 02:52:01 AM »
Following along Brian  :popcorn: :popcorn:

Thanks Mike--I generally take a couple of weeks between builds, but with this damned virus there is absolutely nothing else to do.

I’m with you there, I’m not looking forward to finishing the Witte, I’ll need another project or I will go stark-raving-mad  :o

And actually, I may have a doozy in the works!


Scale Dusenberg engine?

Offline Brian Rupnow

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Re: Stephenson's Rocket
« Reply #86 on: May 19, 2020, 05:25:58 PM »
The outside of the rectangular areas of the cylinder have been machined this morning, all except for the radiused area. This was simple stuff, with the cylinders held in my milling machine vise. The rest of the things I have to do are mostly all rotary table work, so I need shafts mounted in each of the cylinders for my 3 jaw chuck on the rotary table to hold onto.  I could have made an expanding arbor to mount the cylinders on, but this works just as well. I cut a couple of 5/8" cold rolled steel shafts, long enough to stick out each end about 1", and Loctited the shafts into place. After all my machining is finished, a bit of heat applied to the cylinders and the shafts slide right out. If any loctite residue remains in the cylinder it will easily come out by running a 5/8"reamer thru.

Offline Brian Rupnow

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Re: Stephenson's Rocket
« Reply #87 on: May 20, 2020, 11:35:43 PM »
Shopgeezer was asking how I machined the radius on the cylinder. This is a picture of my set-up. I'm end-milling with a 1/4" diameter endmill. The endmill is cranked down until it contacts the part and is locked there. The travel stops on the front of the mill are set to keep me from running the endmill into the larger diameter bands at each end of the cylinder. The mill bed travels in the X axis to the extent of the travel stops, then cranked back, and the rotary table is indexed about three degrees, then repeat---and repeat---and repeat. Eventually you will have milled all the way around to the next "flat" surface on the cylinder. It will need a bit of file and sandpaper cleanup, but it works very well.

« Last Edit: May 21, 2020, 12:07:12 AM by Brian Rupnow »

Offline Brian Rupnow

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Re: Stephenson's Rocket
« Reply #88 on: May 21, 2020, 09:45:23 PM »
I always consider it a huge success when I have to drill and tap 20 holes, drill 20 clearance holes, and all the parts fit together!!  Tomorrow I will probably work on steam chests.

Offline Craig DeShong

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Re: Stephenson's Rocket
« Reply #89 on: May 21, 2020, 10:51:08 PM »
I’m with you there Brian.  Give me a one time difficult task, and I’ll probably get it done without incident.  Give me a highly repetitive task, and the mind wanders and errors occur.  It’s hard to maintain your concentration. Same reason why I never build the same model twice.  It would be “ho, hum; boring, I’ve done this before”.

I have a friend in Ohio who builds engine models on commission.  He has built the same model a dozen or more times; sent his kids through college with the proceeds,  I would be bored mindless.
Craig
The destination motivates us toward excellence, the journey entertains us, and along the way we meet so many interesting people.

 

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