Chris's Build of Steering Engine

[Michael S.]

It's nice to see how well you did the eccentrics.
I think the connecting rods and crossheads are just routine for you.
But the cylinders are very complex. you already do
Other steering machines would not be easier to build either and the electric machine would be a bit boring. 😉

Michael

[crueby]

Yeah, the cylinder shape is complex, but I have no doubt about being able to make them, just need to decide how many pieces and what order to make them in. That's a lot of the fun!

[crueby]

I went back to the CAD model and rotated the crank around while watching the clearance on the eccentric arms to the engine bed, and found that there was indeed a slight interference there in the original design I did. So, I narrowed in the sides of the arms where the bolts go through, and widened the opening in the bed slightly too. For those wanting to build this model, I am attaching a new copy of those plan sheets here, plus the one of the control valve with the angle on the end of the slider that I think I had forgotten to post before.
 

[cnr6400]

 

[crueby]

Todays parts were the con-rod big ends. Started by squaring up (well, rectangularing up since its not a square!) a piece of bearing bronze rod, long enough for the four pieces needed, and drilling the bolt holes:

Drilled/tapped matching holes in a length of steel bar for the bottom plates.


Cut all the pieces from the longer bars, and assembled the two blocks

which were then trimmed to length. The bottom caps are slightly longer than the bearings

Each was then centered up for drilling/boring the crank pin holes

then again to turn the outer portions of each side to form the protruding parts of the bearings

Here are the parts so far, test fit on a length of the same bar the crank pins were made from

Next time I'll start on the small ends and the arms, which will be made from one piece of steel rod...
It will be interesting to see what the weather does in the next few hours here - had very high pressure yesterday now moving out to a very low pressure area, so the winds are starting to pick up. They are expecting us to get several hours of 50 to 60 MPH winds as the front goes through. The generator may get a workout!

[crueby]

Today I started in on the upper ends of the con rods, with a piece of rectangular 303 stainless steel. The ends of both bars were milled down to the final width/thickness first.

Now for a great example of stress in rolled steel bars! I routinely stress relieve brass bars that are going to be shaped down the sides or split lengthwise to keep them from going banana shaped, for brass its easy (an hour soak in a 500F oven). For the stainless, it would take a heat treating furnace since it would be much higher temps for long periods of time. So, if its a bar that will be thinned down, I'll take some of alternating sides to sneak up on the final thickness. If its going to be a complex shape, like a cylinder block with steam chest on one side, I'll go to the trouble of using 1144 Stressproof Steel, which comes already stress relieved. And here is why - these bars were cut down the sides on the bandsaw to remove the bulk of the material and save time turning/milling all that material. You can see how the sides have warped! This is NOT from heat while sawing, they stayed cool, this is due to the stresses induced into the bars when they are rolled to shape in the factory, compressing the metal on the sides more than in the middle.

The middle section was left thick so I could mill to final thickness and straightness, and take the bottom end flanges to size too.


Also drilled the bottom flanges for the screws coming up from the bearing blocks

The parts so far:

Next up will be to turn the middle section round on the lathe. The upper ends will get milled to form the yokes to go over the bottom ends of the piston rods. These bars are long at the upper ends still, to leave a place to grip them while shaping the yokes.

[Kim]

Great example of the banannafication of a piece of stock!

What is it?  Only 2-3 inches long? Shows just how much internal stress there is in that cold rolled steel!

Kim

[crueby]

Great example of the banannafication of a piece of stock!

What is it?  Only 2-3 inches long? Shows just how much internal stress there is in that cold rolled steel!

Kim

Yup, those cuts were only 1-3/4" long. Over the years I've noticed that it varies a lot piece to piece of bar stock, some warp badly, others hardly at all, a lot probably depends on the processes in the factory where each was made. Best to assume that the bar will warp and cut both sides alternately, and take the final cuts as shallow ones to finish the shaping.

[cnr6400]

 

The guys at the steel distributor near me have shipped Bananium a few times when I ordered hot rolled steel....

[vtsteam]

This an amazing machine! 

Boy that steel really warped a lot. 

[crueby]

Thanks guys!
More on the con-rods this morning, started with turning the shaft on the lathe

then drilling the cross pin holes

and chain drilled the holes for the open sides of the yokes

then connected the dots and took the slots to width

To round off the yoke ends, made a little arbor by drilling/tapping a hole in the end, and milling a shallow slot for the yokes to fit into and keep from turning. Then milled the corners off, spinning the chuck on the rotary table

A little cleanup filing, and then will make a slot for the key to keep the pin from spinning...

[cnr6400]

Rod's looking great Chris! 

[Michael S.]

Chris, thanks for showing.
Now I know how to make the connecting rod on my Nicholas. It looks good the way you do it. 👍

[crueby]

Chris, thanks for showing.
Now I know how to make the connecting rod on my Nicholas. It looks good the way you do it. 👍

Rod's looking great Chris! 

[crueby]

More trimming and filing on the con rods, here is what they look like so far

They need some more finishing work, and they will be ready for use.  I think its time to work out how I am going to make the cylinders, need to spend some time working out the order of things to shape them, they are a complex shape and I dont want to get stuck needing to trim something and not having a good way to hold it. These cylinders and valve chambers have blind bores, they don't go through the bottom except for the rods. I much prefer being able to run all the way through with the boring tools, so I am thinking of making screw-in plugs for the bottom ends of the holes, a lot like I did for the Stanley engine. I have a Sherline short lathe bed set up for thread cutting, and can do a one-off thread for the plugs since it won't matter if its a standard size or not, just need matching threads on the plugs and bores, so I can do a large size fine pitch thread.

Recently I mentioned the plans I found at the National Archives for the steering engine on the Kearsarge battleship from the ship class just before the Ohio class that Dave gave me plans for. Been looking through those sheets, and I'm really glad I built this engine first, otherwise I would have no clue how the parts on the Kearsarge one went together - they have one sheet of general arrangements, all the other sheets are individual parts and very few subassembly drawings. Will need to get that engine into the build queue (which keeps getting longer!)  One model I've wanted to build since I was a kid is the steam hammer like the Stuart one - I remember seeing it in the print catalog (remember those?) way back when, and think it would be a very interesting one to make. I found out a couple years ago that Stuart Turner sells the plan pages for their models seperately from the kits, and had purchased a copy for the steam hammer. Last month I put in an order for just the column casting from them, its the largest part of the kit, and would be tough to make with my tools. Hoping to get that in January - they said they did not have any in stock, and had never cast that one so they are setting up the patterns they have for it to run off some. Guess that happens for a low-sales kit when the company changes hands. Should be about the right timing for after the steering engine is done - once the engine itself is done I still want to make a stand that includes a deck section and a partial rudder for it to turn back and forth.

Anyway, off to lunch then time to do some detailed plotting and scheming on how to make the cylinders!