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Discussion Starter #1
The N class were 2-6-6-3 Freight trains used in the Northwest
The N1 was a saturated steam compound which was not very successful
The N2 was an improvement as it was superheated but still had power problems as the slide valve LP cylinder could not handle the exhaust volume and had a top speed of 20 MPH
The N3 was a simple Mallet with four superheated cylinders. A Coffin feedwater heater was added and attached to the front of the smokebox. A fold back stack extender was also added.


The model of this standard gauge loco will be in 1/32 scale with 5/8" cylinders and a butane fired ceramic burner.

Last week I ordered the wheel castings from Walsall and gave my frame drawings to Dennis to CNC mill. he also cut my gaskets on the laser and brought them over today.


In looking at the photo of the front chassis, I see that there is a lot going on with lots of fittings on top of the cylinder and a huge exhaust collection cylinder built into the cylinder casting with a U shapped pipe going from the front of the cylinder to the rear. I figure it was done like that to allow enough room for a flexible fitting at the smokebox.


I started the cylinders by rounding off one corner of the 1" square block on the router and then cutting it and all of the flat stock to the same dimension on the table saw.


The cylinders are then bored out to .615 and then reamed to size with a .625" reamer


The mount holes are drilled out in the mill and then tapped out on my Mycromark tool.


I am using slide valves so I make a cross porting plate do display the correct valve positions. in the photo, there are two plates showing both sides of the plate.


A side cover is made from .032 brass sheet, rivet embossed and bent to shape.


End caps and a test bent tube are added and I think it is ready for paint.
 

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2-6-6-3?
Which side of the rear truck are you adding the extra wheel!!!
You just keep getting better and better at this.
Stay safe,
David Leech,Delta, Canada
 

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Discussion Starter #4
Actually David, the third wheel is trailing the first two to keep it from popping a wheelie if the throttle is opened too quickly
 

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Discussion Starter #5
Dennis came by Weds and dropped off the CNC frame rails and the laser cut gaskets.


I showed the photo of the front in my last posting but it wasn't very clear. I then noticed this drawing on the cover of a book I have which shows how the exhaust piping goes. You can see that it picks up the exhaust from two chambers in the valve body and then makes a U turn onto a larger fitting that was either a ball joint or a dog bone type of fitting. The reason for the front fittings and the U joint was to allow enough room for the swivel and telescoping fittings needed to connect to the smokebox.


It would be impossible to bend 3/8" tubing that sharply. Solid may have worked but it surely wold have been distorted. I had some 3/8 od and 1/8 id silicone tubing which fit the bill. I annealed a piece of 1/8" copper rod and ran it through the tubing to get the bend I needed


Leaving extra rod in place the tubes were bent to shape


I taped them with masking tape to mark the cut needed


And cut them on the band saw. A piece of wood held one end up to get the angle I wanted for the rise in the tubing


A fitting that may resemble the ball joint was made and everything was glued on with E6000


Finally everything is painted and a buffer beam and deck are started.




 

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Discussion Starter #6
I soldered up the boiler last week. It is quite large and should produce plenty of steam.






The smokebox is relieved at the bottom so I mark it off and do the cut out on the band saw


I then silver solder the flat pieces on and sand them flush after pickeling.


The boiler and smokebox are then set on blocks to make sure the front truck will have the proper clearance.


The cow catcher is a tube type mounted under the coupler. It has 18 tubes which scale out to 1/16" so I use 1/16" brass rod for the tubes as it is stronger that tubing and easier to bend. The lower frame is drilled out with spacing of .135" and the upper will get .113" spacing. everything is silver soldered together except the tubes which use Staybrite.








A headlight with the proper square bezel for #52 id made and everything is painted


 

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Discussion Starter #8
The ceramic burner is huge on this engine as it will take up the firebox and the combustion chamber area
The area between the drivers needs to be narrow so I cut out the bottom to that shape and bend the front of it up before soldering it to the sides.


Then pieces are soldered in place






The critical part of this is making the jet holders as the dimensions must be exact. Not shown in the drawing is the inside bore which is the same as the outside of the jets which is 5/16"


now the burner is tested while held in a vise. The little standoff barriers are adjusted for size, shape and position till I get an even burn.





The edges are sealed with high temp RTV and the job Is done.
One final test is done in the boiler to make sure it will pop back when lit through the stack.
 

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Bill, I read these posts and see the images of your creations and I truly amazed at the fine work you do. My father was a tool designer and tool maker back in the 40's and 50's. None of that craftsmanship rubbed off on me but I can sure appreciate the detailed work you do!!!!!!!

Great job.. :):):):):):cool::cool::cool::cool:
 

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Hi Bill, another good model you are making and also many thanks for sharing your knowledge, so regarding the ceramic burner and it's design I have a few questions... I see you make two standoff barriers are they to deflect the gas to feed more of the area of the ceramic for an even burn and how critical are these barriers in both two jet and single jet designs?
Is there any height/ width / angle that is a good starting point and how far from the nozzle should they be? How much "space" do leave for gas under the ceramic and how critical is that?
While I am not making a ceramic burner right now it is your expertise and knowledge that will help if I do in the future and also trouble shooting existing designs.
Russell
 

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Discussion Starter #11
Thanks Stan
Russell
The standoffs are trial and error. Without them the burn usually goes to the end of the burner the standoffs block some of that and diverts the flow backwards. they don't go all of the way to the bottom of the ceramic plate but about 75% of that. Usually at least 1/2" of space is required under the plate for correct mixture and distribution but in the front sides over the wheels there is only 1/8" but the center channel provides enough access to those spaces.
 

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Discussion Starter #12
There is a diverter/extension on the stack that is in the stored position in every photo i have seen. It looks like it was held in place with two bolts that would be loosened to raise it and could be removed to reposition it to point left or right. Mine will do the same thing.




The extension was made from sections of pipe welded together to get the bend. I turned my pipe from 3/4" bar stock. To cut it into wedge shaped sections, I first turn a wood dowel to a tight fit inside to keep it from getting bent when I cut it and then using a spacer to set the angle, I cut them on the table saw.


They are then silver soldered one by one to make the unit.


And the finished product is laid next to the photo of the real one.
 

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Discussion Starter #13
The boiler wrap transitions to an upside down wagon top boiler design.
To support it, I am using a ring and wedges. i start by cutting the ring out of plywood


I then taper it on the belt sander and glue it and the wedges on


Then the front sheet is cut and bent and Fiberfrax is attached to the boiler


Supports are made for the firebox. The left side is notched for the lower sight glass tube




Finally the two rear sheets are cut drilled out and bent to shape. They are all soldered with Staybrite and imperfections are filled with JB Weld. The backhead is finished off also.




 

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Nice job on the wrapper. I can't quite tell from your boiler photos if the fire box has dry legs. Is that why the lower pipe to the water gauge runs forward past the fire box?
 

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Discussion Starter #15
Yes Winn, the dry leg firebox works best on ceramic burners as it allows for more tubes and a bigger crown sheet. I have tried both and the dry out performs the wet.
 

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Discussion Starter #16
I received the wheels from Walsall last week. Here is a photo of the rough and the finished casting


I start by mounting the wheels in the external jaws of the lathe and drill out the axle hole and face off the back till I expose the spokes.


I then mount it in my arbor and face off the front to 6mm wide and do the tread profile to .020" over the final dimension




I then go back to the external jaws and face the hub off to 1/4"
On Dennis' lathe we do the tread profile with a plunge tool.
Finally, I attach the counterweights with JB Weld and paint them.


The feedwater is a little more difficult than one might think. I first start with a frame made from two curved pieces Dennis cut on the CNC mill. the inner one has three tabs for mounting on the firebox front.
The two bottom pieces are notched out for alignment and the two short pieces are to keep it square.




The coverings are cut from 1/32" stock and annealed. The inner one is notched out for the tabs to clear and the assembly is silver soldered together.
The coverings were made a bit oversize to be sanded flush.


Because this is a simple engine, superheated steam will go from the rear engine to the front. A manifold is made at the rear engine and a dog bone connection will provide the swiveling and telescoping junction between the two chassis.




I want to keep the steam as hot as I can so I insulate the 5/32" copper tubing with string which has been impregnated with Carborundum glue and painted with bar-b-que paint


The next photo shows the connections between the chassis.
The upper pipe is the rear engine exhaust.
In the middle connection, you can see the dog bone and to the right the insulated tube to the front engine.
The bottom tube is the steam supply coming from the smokebox
Just below the dogbone, you can see a rod with a yoke on the right. This is the reversing lever.
To the left of the cylinders it looks like the rod passes under a bar spanning the frame rails but it is actually going through a hole in it keeping it in line with the rear frame and controlling the bend in the rod to jibe with the front chassis articulation.


The two chassis mounting heights are determined by the weight the boiler distributed on them. Simple Mallets are notorious for front chassis spin so I moved the center mount back a bit to put more weight on the front. I will measure again when all of the accessories and water is added and can shim some to get the best balance at that time.
 

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Great project Bill. Those engines really intrigued me since I saw a photo of one from K. Zimmermann's book on the Milwaukee electrics. Its funny that none are seen in the film Danger Lights its all Mikados. The Milwaukee was a great fallen flag.
 

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Its funny that none are seen in the film Danger Lights its all Mikados. The Milwaukee was a great fallen flag.
Simon,

That would largely have to do with the time and location of the filming of Danger Lights. It was filmed Largely in Miles City, MT and in a few other locations around the MT area (Sixteen Mile Canyon) along with Chicago, IL of course.

Timing is the other factor. Danger Lights is a 1930 film, largely filmed in 1929, the year the N3 rebuilds started. It is likely not many of them were either complete or working in the area of Miles City at the time of filming.

Like their original designs, the N3's were found in both regular service and pusher duty on the Chicago, Milwaukee & Puget Sound Lines; even after the electrification of the mainline of the from Tacoma to Othello, WA (hence the stack deflector, for the numerous tunnels along the Pacific extension).

They could be found running on the Elk River branch and the entirety of the non-electrified section of the Pacific Extension in Idaho. Another area where they saw use was the Everett Branch in WA, on the Coast Division.
 

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Discussion Starter #19
Ryan
It amazes me how you know so much about every line and loco.

I am taking a week off from building and am in Lake Tahoe with the family (16 of us)
Went to Virginia City Yesterday and rode the V&TRR from there to Gold Hill and back
The engine was a standard gauge consolidation. Not sure if they ever ran one of those in the day but it was fun. My son said they were all taking in the scenery and deer & mustangs when he looked over at me and was studying the rivets on the tender
 

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Discussion Starter #20
The sand domes are different. The front one is low and wide and the rear narrower but higher.
On the front one, I start by cutting out a wood block to shape and then wrap a piece of card stock around it
I cut the approximate boiler curve on the bottom and then set it in place. Then using a pencil held firmly on it's side, I mark the final cut.




I remove the card stock and use it as a template glued to the brass sheet with spray adhesive


I cut the top to shape and silver solder the dome together


The rear dome top is 3/16" thick as it will be rounded off after assembly. I get the shape by setting the compass to 1/2 the width and making two center pops which are separated by the same measurement as the length minus the width.


The side is done the same way as the front one.The top is rounded off with the 1" belt sander after soldering.


Finally the running boards, air tanks and cooling piping with the rt side tank being the lubricator, bell, generator, clack valves and piping, water heater piping and hand rails are added
The large pipes on the side were the rear engine exhaust which is where the water heater picked up it's heating steam.

Next up cab, safeties, and tender





 
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