The Home Machinist!

Hi everyone,

With the 1918A's behind me (still plenty left!), it's time to dig into the 4000C's.
As the title mentions, this projects has been completely redrawn in 1.5" scale to better suit Jim Kreider's Berkshires. Even if they go on a 1.6" locomotive, they're still a mammoth injector in 1.5"!

Taking lessons learned from previous projects, many design improvements were made in the process of redrawing the 4000. A number of things were corrected externally to make it true to the prototype as well.

The water and steam valves have a sleeve around them that functions dually as a filter. The lever lifts both steam and water valves simultaneously, and the position of the lever regulates both steam and water, so the tender water valve can be left open, even with the injector mounted below the tender. The nozzles are the 6.5 pint per minute variant, however by cutting back the lever the capacity can be reduced to approximately 60%.

With the lever left open fully, it can be used normally with a turret mounted steam valve and tender water valve.

I'm very excited to start this project. It's going to present some serious design challenges! I'd like to use this thread to document some of the progress; something I tend not to do.

Hello Anthony,
Watching your topic with great interest! This type of injector seems to me the most desirable due to the combined water and steam valves
What a pitty to me, that it won't realy fit to my A 1239 of scale 1 in 10
Thank you for posting those rich details of this masterpiece!
Asteamhead

Today I had the "pleasure" of making the long drive on I-5 from the SF bay area back to Southern California. The repetitive scenery gave me plenty of time to think over some things on the 4000C, and the primary item of concern was the operating lever.

I was considering offering an operating quadrant as an optional accessory, but after thinking about how they function it became apparent to me that they really ought to be included. The single handle allows full control over the injectors operation: shutoff, priming, running wide open, and fining down the capacity.

My original valve design (shown in the first post) would not allow this functionality in the handle, at least not completely, so I had to go back to the drawing board and figure out how to make it work like the prototype. Meaning as the handle moves further back from "wide open" it actually closes the water valve. Seems like a backwards thing to do, but my original design would have required an external valve to cut the water down below 90-100psi. Now, with the valve redesigned to simulate the prototype, the injector can be operated with one handle throughout the entire operating range. Perhaps Nathan knew what they were doing.

The side effect of this change is that the injector can't be forced open and used like a regular injector, since propping it wide open would actually be propping it shut. This is why it became apparent to me that the quadrant needs to be included.

Seems like every time I try to take liberties in model design it always ends up not working quite how I envisioned, and to get it to work correctly, I end up going back to how it was done on the real thing.

All that said I'm very excited about this development. Hobbyists fell in love with the simplicity of a single lever on Barry's Nathan Simplex, but with the Nathan 4000C you'll have vastly more control with the same simplicity of a single lever.

Still a few things to draw complete the quadrant assembly, but here's mostly how it will look.

And for some reason, something told me that when I did the cradle casting that I should put the brackets for the Nathan 4000 on the casting, just in case. Well the brackets are there as you can see in the photo. Then along came Anthony and Eccentric Engineer!!
Jim Kreider

Would be very neat to see you offer some sort of cab control water stand for the 1918 as well.
Looks great!

Berkman,

The 1921 starter valves were made to be paired with the 1918A's, and I'll have universals available in a few weeks for anyone that wants to run the water valve to their cab floor. The bracket that was used to support the valve rod was very simple.

Anthony

When in doubt; how were the originals made? A former coworker from the Southern Steam Program told me that. Make it like the prototype, that way you know it will work.

Both locomotives had a Nathan 4000 injector. The were simple to operate. Pull one lever and it’s on. Very complex innards though.

Makes me wish I was building some big modern locomotive to have one of these on one side and David Moore’s Worthington pump on the other.

Andy Pullen

Made the mold for the quadrant handle today. Was tricky to figure out as it doesn’t part neatly down the middle. A few plugs and pins to make all the holes and undercuts as well.

I considered scaling it up to make it easier to use, but now seeing it, it’ll be perfectly comfortable to use in 1.5”

There’ll be a fairly simple machining operation on the casting to make clearance for the tooth that engages the quadrant.

Cut the mold for the quadrant bracket this morning.
The next piece will be the handle latch: the little piece you squeeze to free the tooth from the quadrant. It’s the smallest casting of the entire injector yet will require the most complicated mold.

Anthony,
that quadrant of 1.5 " scale would give a chance to me to use it for my A, too due to the desired additional size for better handling
Looking forward to your process!
And not to forget, whish you a better New Year!
Asteamhead

Beautiful work as always Anthony!

The mold for the handle latch is done. Took longer than the other 2 combined when you take CAD, programming and setup into consideration. 2 metal cores and 5 pins to put the little 1”x1.5” mold together.