Chris's Build of Battleship Ohio Engine

[Kim]

Only one off?!  This part will go by like lightning!   

Kim

[crueby]

Only one off?!  This part will go by like lightning!   

Kim

     

[crueby]

The eccentric is done, time to shape the strap for it...

[crueby]

You were right Kim, this one went pretty quick!

Now can start in on the pump itself. Its a two cylinder single pump, driven by the eccentric, pretty much a larger and slightly more complex version of the plunger type hand pumps we use for testing boilers. One plunger and cylinder on either side, the vertical chambers are anti-knock pressure chambers. For the model the plungers will move, but I am making the rest of it a dummy pump, no need to actually pump anything since I'll be running it on compressed air. On the plans, they call it a Sanitary Pump, its not part of the boiler/steam system as far as I can tell. Hard to know for sure since the plans dont show the rest of the system.

[ddmckee54]

Chris:

Regarding the eccentric...  I'm puzzled by what appear to be a pair of rectangular-ish openings on the LH side in your last picture in Post #1307.  (Look in the area milled out.)  Is this just an optical delusion, or do those openings exist?  If they exist, what are they for?

Don

[crueby]

Chris:

Regarding the eccentric...  I'm puzzled by what appear to be a pair of rectangular-ish openings on the LH side in your last picture in Post #1307.  (Look in the area milled out.)  Is this just an optical delusion, or do those openings exist?  If they exist, what are they for?

Don

In the CAD drawing? The original did have several recesses and openings, I presume for saving weight and metal. They were too small to mill in on the model parts so I have simplified them a bit. I just included the larger ones in the eccentric next to the shaft hole.

[Michael S.]

In the book for the sea machinists these pumps are described as feed pumps and bilge pumps. However, this machine in the picture is significantly smaller.

Michael

[crueby]

Interesting how the linkages differ between the picture you found Michael and the one in the Ohio plan, on the one from your book it has a tab at both sides of the eccentric strap to connect to the plungers, where on the Ohio plan there is one tab, and they ran rods over to the other plunger. Same end result, two ways to make it.  I wonder if for the Ohio they wanted to make the two plungers into one rigid unit to reduce side loads on each plunger as the eccentric angled over.

 

[internal_fire]

On the plans, they call it a Sanitary Pump

I found this with Google

Sanitary System-To supply sea water for the various toilets aboard ship a steam pump known as the sanitary pump is provided. It takes its suction directly from the sea and is usually controlled by an automatic pressure regulator so that the pressure in the sanitary line remains constant no matter how much water is being used.

Do not flush toilets in daytime. You may give away the location of your ship to the enemy.

https://maritime.org/doc/merchant/engineering/part4.php

I think this says you should only test your engine at night. 

Gene

[ddmckee54]

Chris:

Look in Post #1307, the one before the CAD drawing post.  Look at the LH opening in the eccentric.  It ALMOST looks line there are a couple of rectangular openings there.

Maybe the elves spiked my Grog?

Don

[crueby]

Chris:

Look in Post #1307, the one before the CAD drawing post.  Look at the LH opening in the eccentric.  It ALMOST looks line there are a couple of rectangular openings there.

Maybe the elves spiked my Grog?

Don

Those are just tool marks from when I chain drilled the arc for the opening before milling it out. Just scratches on the surface inside the arc, the light caught them just right in the picture.

Now, the elves may have ALSO spiked your drink...   

[crueby]

Started roughing out the brackets that hold the plungers for the pump this morning, yesterday was out of town at a RC boat event, great fun there.  These brackets will hold the plungers either side of the eccentric, with cross rods between them and on the sides of the eccentrics. One of the brackets will have the pivot to attach to the eccentric. Going to silver solder the parts together, lots of nibbling on the mill next to finish shaping the brackets.

[crueby]

After nibbling away at the parts on the mill, the brackets are close to done. I still need to make and install the short bits of tube to hold the crossbars to connect the two brackets around the eccentric:

[cnr6400]

  Looking great Chris!

[crueby]

Thanks Jeff!

While waiting for the plunger parts to clean up in the pickle after soldering, I started in on turning the pump cylinder and chamber pieces. Simple turning on the outsides, then turned them sideways in the 4-jaw to drill/bore the hole in the side to take the cylinder. They were too long to put in endwise to the jaws, so used the old trick of turning the part 45 degrees between the jaws and gripping with the angled faces.

The parts so far. The cylinders will be held in place in the holes with some retaining compound since they wont actually be under any pressure. I drilled a hole through from the pipe flange on the end to let the air move freely as the plunger moves, after a quick test where it was building pressure.

Next up will be to make the crossbars that connect the two plunger brackets. Soldering those brackets was a bit of fun, I milled notches on the corners for the tubes to rest in while soldering, and did one corner at a time with the bracket tipped to keep the tubes from rolling out. After the crossbars, I'll make the brackets that hold the cylinders onto the engine bed, which has extensions on that end to take the brackets...