building the boiler jacket, pilot, saddle, and cab

It’s been a while, hasn’t it! I’ve been busy with school work and interviewing for jobs, so I haven’t had much time to put the model together. Instead, I’ve been prepping individual pieces here and there–getting them ready for the major assembly.

Last update I said that I redesigned the cab and pilot parts. So, I’ll show you that first.

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I mainly redesigned the pieces to fit together better–there were problems with the first cab where the cab wasn’t truly squared. Also, the posts have been realigned so that their grains run vertically–previously they ran horizontally.

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The new pilot now have the little bumpers on the side.

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And here it is painted in special red: my custom mix of bright red and a touch of black and glossy lacquer.

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The pilot truck is painted and fully assembled. A neat little feature is that–because it’s built like the real swing-type pilot–the casting piece actually does swing! But that’s of little consequence in a static model. Nonetheless, it shows how well the model reflects the computer model, which of course reflects the real engine.

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The saddle is painted as usual, but the steam chest gets wrapped in real brass sheeting.

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And the same technique was used for the domes. The brass will get cleaned and polished before they get placed on the boiler.

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And to a larger extent, the boiler gets wrapped in thin steel sheeting, which will of course get painted glossy black.

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The wrapping around the backhead was notoriously difficult. As is the result of working with sheet metal at such small scale, there are some scratches and bumps on the jacket that I’ll have to smooth out. But I think the paint can help hide them.

redesigning

I decided that the wooden parts could use another iteration of redesign. This will delay the completion of the kit a bit but I think it’s worth it.

Both the cab framing and the pilot were redesigned to make assembly a bit easier and make the parts more accurate to the real counterpart (within the limits of material, that is).

Here’s what the layout looks like, to give you an idea of how many parts there are:

The kit will of course comes with its own set of assembly drawings. Here’s a page showing the cab framing identifying the sub-parts.

the ckh kit first look, part 3

Yea I know, how many “first looks” can there be?

In this update, most of the “recognizably steam-locomotive-ish” parts came in. Here’s the spread–and it may not look like it, but there are nearly 60 parts in this picture.

Unlike the prototype boiler I showed you in the earlier update, the final boiler in the kit will include the jacket’s thickness. The picture of the backhead shows some cutouts for the valves and hardware.

Details like intricate moldings around the domes and headlight panel beveling are exact to the engine plan, and of course the real engine. Note that although I designed the eagle for the top of the sand dome, it turned out to be too small (thin) for the machine to reproduce. So, the elusive eagle got away again!

Check out the bolt heads on the smokebox front, and the riveting detail on the smokestack! For the kit, I redesigned the stack’s wall to be thicker than the real engine’s (the real stack is made of sheet metal) to give the part some structural integrity. As a result, the stack’s opening at the top looks a bit narrower than the real engine would.

Here are some of the very small parts, the lifting shaft and one of the links and its block. And checkout with webbing on the inside of the pilot wheel.

And finally, here’s the boiler with the domes and the stack dry fitted. It’s looking like a train!

first look at the CKH kit, part 2

The kit is not made entirely from plastic. The cab, pilot, and the pilot beam are made from birch wood. The pieces are laser cut for accurate fitting. Of course, they were designed directly from the Plan Book. Here they are in the bag from the manufacturer, and again sorted over the layout drawing.

All pieces are 1/8″ thick, which initially made me concern about the pieces being out of scale. But when they’re assembled (see below) this effect is not at all obvious.

The real cab have recessed paneling and molding. The panel molding is too small and impractical for the scale, but the recess is achieved by laser engraving–partially cutting the panel piece to simulate panel recess!

Ok, let’s put it together: I started with the front panel, then work my way around to the rear and the roof. Since the pieces were made from the Plan Book and mirror their real counterpart, putting the model cab together is also like building the real thing, with posts and panels to fit together rather than pre-completed walls. I think this gives the model very good looking panel lines.

Here’s the front panel fitted on the boiler. The curved panels fit on the boiler just right.

The rear walls also have recessed panels.

The angled roof rafters complete the cab’s framing! Note the small hole at the center of the front header. This is for the whistle lever. I’ll need to drill a smaller hole for the bell rope (I think it was too small for the laser to cut). There’s also the window sills.

It took me about 2 hours to complete the cab at a leisure pace.

To save some costs, the cab parts do not include the actual roofing, and it would also be out of scale with 1/8″ wood. Instead, I’ll complete it with very thin wood sheet. Or better yet, use thin wood strips to actually plank the roof.

Assembling the pilot has two parts: building the frame, and building the bars.

And completed:

Note the bars are a little bit longer than the bottom triangular frame. This is to allow them to be slightly shaved off at an angle and sanded so they’ll have the smooth, curved appearance seen on the real pilot. (The curve’s contour can also be seen in the Plan Book).

Even without working the bar faces to a curve, I think it already looks pretty good.

The bars are a little bit oversized for the scale, so the model pilot have 2 bars less than the real pilot. It’s not really noticeable unless you count them, but I thought you should know.

first look at the CKH semi kit

The model prototype is finally here, and it’s a good feeling to finally hold the physical model after months of work. And it really affirm that the model is really happening!

Let’s take a look!

At 1:20, the model will be about 13″ long when finished. This size will be able to accomodate a lot of details to the engine.

The model is made by 3D printing. This gives it more detail than a model made from CNC manufacturing. Check out the staybolt details on the firebox! There’s even spring hangar bearing surfaces on the frames, and hook points for the tender chains on the drawbar!

The round raised area left and right are boiler washout plugs. The middle is the blowdown plumbing attachment point.

They are a couple of things that should be observed about this model:

1. This was made from the first prototype model, the one without boiler jacket and saddle finishing. Final version of course will have those.

2. The surfaces are a bit rough as a result of manufacturing, with some white powder residue. Ruling on curved surfaces are obvious because of the same, but these can be sanded away easily.

The engine’s 2 frames. The upward bend on the forward legs (right) is a result of manufacturing process, and can be bend back to correct easily (but it still supposed to have a 1-degree incline)
The kit will have tiny details such as the bearing surfaces for the equalizing spring hangars.
Really tiny details: the tender safety chain hooks on the drawbar.

3. Some parts, especially the frame, is a bit flexible. It may require the user to add metal supports to the forward leg to actually hold the weight of the engine. The upward bend is also the result of manufacturing, but I was able to bend it back down in place.

And 4. Some parts are “warped” very slightly due to manufacturing tolerances. This, I think, won’t be noticeable when the engine is finished, but I thought you should know.

Saddle (this prototype is without cover)
Under the saddle is the circular mount for the pilot truck

I really like that the details like how the staybolt heads on the firebox came out. The spokes on the driver tapers like it should, and even the tender hook on the drawbar came out great.

Extremely accurate driver
Spokes are tapered outward as they should

The final kit will have over 60 parts (maybe 70). This preview is only showing 5! I’ll show you know what they are later, but they will make a very accurate CK Holliday. Or, the kit can be a basis for many other 4-4-0, such as the EP Ripley, since there are very few Holliday-centric parts (I think less than 4).

Reverse of the driver shows some manufacturing process leftovers
Dry fitting the parts

I ordered the rest of the parts so I’ll show them here when they’re ready. Now, I’m off to the hobby shop to get some supplies to put this thing together!

kit news

There’s a slight delay in producing the first CKH semi-kit. Hurricane Sandy took out the manufacturer’s power so I’m waiting for them to restore services. The original estimate to have the prototype ready was about today, but now there’s going to be just a bit of delay.

In other news, in addition to the plastic chassis and boiler kit, the semi-kit will also include precision laser cut wood parts for the cab, the pilot, and the pilot beam, so now you’ll also have authentically wooden cab and pilot. The cab is going to be very slightly over dimensioned due to the type of wood and machining requirements, but it will also have recessed panels.

new eye glasses

For a long time now, I’ve been offering some of my Disneyland Railroad drawings for anyone to download for free. These drawings were made with the information that was available at the time, but they certainly weren’t “engineered” drawings.

My “rebuild” of the CK Holliday, however, was engineered from the ground up, starting with just the frames, and then built up and outward. This certainly is the most accurate way to portray the engine.

So, what happens if we compare the old drawings with the new? Well, it’s kind of like getting a new pair of eye glasses–suddenly there are details that just weren’t there before!

Let’s take a look at some of the comparison highlights.

The old drawing that you can still download today is in the background. Most obvious is is the driver: much more detailed and realistically proportioned. The air brake cylinder is properly attached to the frame. And we know that the spring equalizing system in the new drawing is correct and “just works”, because each piece was built in the CAD, not “guessed.”

The backhead detail–what is there more to say? Take a close look at the firedoor, throttle , and the gauges stand. The plumbing in the new version is also richly detailed because, again, they were actually “built.” Each bend is exactly as it should be. Components like the valve wheels and gauges were recreated to the manufacturer’s specs, too.

The new drawing doesn’t show the gauge faces here, but a detail is included in the Plan Book.

Everything here is more detailed. From the recessed cab paneling, the boiler’s front, pilot, and the array of pipes and fittings on the air compressor on the drawing’s right side. Also, the smokebox braces are thicker, and curves down correctly.

So, in conclusion, if you’re looking to approximate your model, or just want to get a general idea of the engine, the free drawing will get you there. But if you want a complete understanding of the engine, or want a model with correct details and proportions, I think, the Plan Book is a must.

the little details

There are a lot of things to consider when making a scale model.

When people see the computer build of the Holliday I did on this site, most people would think that they should be able to just send it to a 3D printer or a CNC machine and have their own scaled copy of the famous engine to sit on their desk.

But there is a lot more work than that–a lot of issues to consider. The most governing issue is the size. Larger model will accommodate more details, but is expensive and inconvenient for most people. A model too small won’t have many of the details that are unique to the engine. So there’s a balance somewhere.

What about the materials? People think metal like aluminum, steel, and cast iron are authentic and durable, but they have terrible details and tolerance, and are hard to modify.

I also have to redesign the parts to make them suitable for small scale. This is because very small details like bolt heads or cotter pins can not be reproduced by machines. So, I have to take the full scale parts and delete or simplify the details (of course, I’m working with a different copy of the part!).

And the material? Plastic gets my vote. It’s the easiest to work with and modify and add details. They’re also lighter in weight which saves on shipping.

And which parts are important to the modeler? With a copy of the engine plan book, one could build a model with every single detail that is found on the real engine. But, when scaled down, some of those parts are impractical. And scratch building it would be tough. How would you go about making the drivers, boiler, saddle, etc.?

But, there can be a CK Holliday semi-kit, and modelers wouldn’t have to worry about any of the above. And maybe it will look like this:

Note that the parts like footplate, side sheets, running boards, and deck are very flat pieces that I think the modeler can fabricate himself (just cut them from a styrene sheet, or even thin metal sheet). The parts will be made of polyamide (PA2200) plastic–strong but flexible enough to work with (they’ll take some abuse).

The intention also is to allow the modeler to build his kit like the real engine, which means the saddle you see above is just that–the saddle. The modeler will have to furnish his own finishing, such as steam chest cover, on top of that, which I think is great so anyone can customize the finishing to match his favorite 4-4-0. Also, the modeler will understand how the engine is really put together–he’ll have to assemble and key the drivers to the axles, and place the axle boxes in their jaws, etc. Not much is “pre-done”, except the boiler is “pre-jacketed” which one can paint–or even better, wrap it with thin metal sheet–just follow the contours!

(Speaking of the jacket, you can see how it has cutouts for the domes and the running board brackets already!)

There are still a few more parts I want to add to the above (crossheads and rods comes to mind). Then, I will experiment with some laser cutting wood to provide for the cab.

The above picture is just a computer preview. I’ve sent a few parts to be fabricated so we’ll see how they turn out. Standby for updates and more details on the semi-kit!

UPDATE: New rendering of the prototype below. The 1:20 semi-kit will contain just about what you see below, except for the cranks and the crosshead guides, which anyone can make (they’re included in these pictures just for purpose of completing the assembly).

The cylinders and domes covers can be painted, or better yet, wrapped in gold foil to look like real brass.

Note the backhead has cutouts for the throttle plate, washout plug, and some of the plumbing.

What should a CKH semi-kit have?

This is not indicative that a CK Holliday kit is forthcoming, but to help make it so someday, please voice your opinion on what parts you would like to see if you were to purchase a CK Holliday semi-kit.

Select as many answers as you want, but remember that as you select more parts, the price of the semi-kit will go up! So, try to be conservative, but it’s still like a wishlist so you’re really free to mark whatever you want.

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Also, how big should it be?

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Finally, please select the range of prices that you’d be willing to pay for a semi-kit containing parts you marked above.

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Thanks!