Kozo A3 in 1.5" scale - new project

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kvom
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Joined: Thu May 08, 2008 11:38 am
Location: Cumming, GA

Re: Kozo A3 in 1.5" scale - new project

Post by kvom »

Machined the mounting ring for the steam dome. It will be TIG welded to the boiler, then drilled and tapped. Show in position:

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VO4454
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Location: NorCal

Re: Kozo A3 in 1.5" scale - new project

Post by VO4454 »

Kirk, Looks like a much better design. I can't tell from the photo, but will you be able to remove the elbows should the need arise?

Vic
For Duty and Humanity
kvom
Posts: 1163
Joined: Thu May 08, 2008 11:38 am
Location: Cumming, GA

Re: Kozo A3 in 1.5" scale - new project

Post by kvom »

The ring fits under the one elbow, so the two will be able to be removed together. I may need to machine a small relief on the ring to clear the elbow that screws into the boiler, depending on where it ends up after welding.

I will be using 10-24 screws for this plus the cap rather than the 10-32 used previously. A bit stronger.
kvom
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Joined: Thu May 08, 2008 11:38 am
Location: Cumming, GA

Re: Kozo A3 in 1.5" scale - new project

Post by kvom »

Got three main pieces cut and ready for welding.

Image
kvom
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Joined: Thu May 08, 2008 11:38 am
Location: Cumming, GA

Re: Kozo A3 in 1.5" scale - new project

Post by kvom »

Got the welding done by a buddy. Here's the base ring welded to the boiler, drilled and tapped:

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A view of the bottom ring of the dome body, drilled to match the base plate. The notch is to clear the elbow.

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An interior view:

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Mounted on the boiler with the lid; safeties and fill plug installed.

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Next is to fabricate and weld the mount for the throttle tube.
kvom
Posts: 1163
Joined: Thu May 08, 2008 11:38 am
Location: Cumming, GA

Re: Kozo A3 in 1.5" scale - new project

Post by kvom »

Short shop sessions today. First, measured and drilled the hole in the dome through which the throttle rod will pass. It's 1/2", but could be enlarged is needed.

Then setup on CNC mill to smooth welds where the mounting flange will be welded later.

Image
kvom
Posts: 1163
Joined: Thu May 08, 2008 11:38 am
Location: Cumming, GA

Re: Kozo A3 in 1.5" scale - new project

Post by kvom »

Made the mounting flange for attaching the throttle tube to the steam dome.

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The 1/2" drill bit will align the two parts together for welding.
kvom
Posts: 1163
Joined: Thu May 08, 2008 11:38 am
Location: Cumming, GA

Re: Kozo A3 in 1.5" scale - new project

Post by kvom »

A friend welded the mounting flange to the dome body, so it was time for some fit checking:

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With a little fettling I got the dome cover and base to fit, although I need to install the boiler jacket to be sure. When I installed the throttle rod mechanism onto the rear of the tube I found that the crank for the valve stem is now too short since the valve sits slightly higher now. I had made the hole in the dome smaller this time (.5" vs .65"), so enlarging the hole may work vs. making a new crank.

Since I'm going to redo the piping and since the Superscale injectors are lifting, I will position them inside the cab rather than underneath the running boards. Test fit of the cab looks fine for this by eyeball inspection.
kvom
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Joined: Thu May 08, 2008 11:38 am
Location: Cumming, GA

Re: Kozo A3 in 1.5" scale - new project

Post by kvom »

Only 6 months since the last post; the engine has been sitting with boiler parts sitting around untended. But now with Cabin Fever past I don't have any shows for a while to get models ready for. So I made new gaskets for the steam dome and buttoned it up. Planning to take the boiler/throttle assembly to the RR tomorrow to do a hydro and see if the throttle leak has been cured.

I needed more 1/8 NPT plugs for the boiler than I had on hand, so I decided to make a batch. Needed 6, made 10. Here are the leftovers:

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First time using a NPT thread mill in anger. :)
kvom
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Joined: Thu May 08, 2008 11:38 am
Location: Cumming, GA

Re: Kozo A3 in 1.5" scale - new project

Post by kvom »

Hydro was a meaningfull success as there was no leakage through the throttle @100 psi. A couple of seeps from tapped connections, but I intend to rebuilt the turret head anyway as well as redoing 90% of the piping.
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kenrinc
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Re: Kozo A3 in 1.5" scale - new project

Post by kenrinc »

Good to see you back at it Kirk.

Ken
kvom
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Joined: Thu May 08, 2008 11:38 am
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Re: Kozo A3 in 1.5" scale - new project

Post by kvom »

Assessing the reassembly and piping project. Club member said copper tube in the smoke box is liable to corrode away, so I just ordered some SS tube and fittings from McMaster. Painted the boiler jacket again. Also ordered some elbows and brass pipe from PMR. I have remade the turret as well without the crappy solder joints. My plan is to get the jacket installed before mounting the boiler back on the chassis, as it was a PITA to do when on. Then sort the smokebox piping.
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