Monthly Archives: November 2012


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.

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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!

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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.


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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!


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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.

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