Tuesday, November 15, 2016

Building and Testing Naval Guns

Whenever I see a video of a big battleship gun being fired, I wonder how the guns are made. The barrels are machined out of cylindrical forgings. The shaft that holds the tool that mills the inside of the barrel slides along a two slide guideway.

The size of the "big guns" on the battleships defined the arms race until aircraft carriers and their airplanes proved battleships were obsolete. (Battleships were obsolete before WWII, but some admirals had to see some sink during the war before they believed it. Fortunately, the Navy started designing and building purpose built aircraft carriers in the 1920s so we had some for WWII. Soon after WWII, the arms race focused on nuclear warheads and intercontinental rockets. I assume satellite and cyber warfare is where the action is now even though we keep building more expensive airplanes.)

John Abbott posted
Naval Gun Factory DC 1943 small
John Abbott posted
Naval Gun
Sean Mullen I just happened to look up the muzzle energy on those big 16" guns this morning. It is a stunning 304 million foot pounds!

John Abbott posted
Gun Barrel Boring Machine Gear Drive ...Because ... I couldn't call it a Gear Case ? ... Get the Grease Gun Boy ...
[It makes you wonder when the industry start putting safety shields on the equipment. People were hurt, and even killed, back then. Now you can understand one reason why.]
Rich Behrends posted
Four cutting tools shape the outside of a 12-inch gun.
Image: Scientific American, December 4, 1915
Rich Behrends posted
DC Navy Yard turning a cannon 1899
Rich Behrends posted
DC Navy Yard cannon boring. Year unknown
Rich Behrends posted
Bethlehem Steel machining big cannon 1899
[Note, this plant has yet to convert from shafts and belts to electric motors.]
John Abbott posted
We are doing over time tonight need more Gun Barrels
[Note the line shaft along the right.]
John Abbott posted
Perry Locke Notice man in crane control platform.
Earl Rempel Think how much of that work is lying at the bottom of some ocean...
Roger Hampson A more intact story is here.
John Abbott posted
Joe's over there doing the Big Barrels on the Belt Lathe...
[Even at full Facebook resolution the text is hard to read. This is what I saw: "Face plate 120" in diameter and swing over shears 130" by 76'. It is geared for turning taper from 1 in 10 to 1 in 400, and there are four carriages with compound rests. The shaft shown in the lathe weights 63,000 pounds and is 37" diameter at the center and 27'4" long." The word "shears" was a guess. I don't understand what that is.]

This 1:33 video focuses on testing various models of naval guns.

A 14:25 1952 video about the US Navy's Naval Gun Factory at Washington Navy Yard.

Update: the day after I published this I came across a silent films of various scenes of making the 16" gun used in WWII. The comments describe each scene. This is the forging step.
Screenshot of  forging a 16" gun
This forging scene does indicate that the cylinder is cast with a hole in the middle that is retained throughout the forging process so that just metal near the edge of the hole needs to be removed by the machining process. The plug also helps hold and manipulate the casting while it is being forged.

Bob Smith posted
This is the first 16" Cannon Tube Manufactured at Watervliet Arsenal. Unfortunately, the seacoast defenses & the Iowa Class Battleships are history, as well as the machines for making them...
Bob Smith The process for boring this 68 foot, 267,904 lb varmint rifle took about 60 hours. A woodpacked reamer head with two HSS cutting tools would be in fed at the muzzle end on a Sunday night & the head would exit the breech end on Wednesday morning. The machinists would listen to the cutters "sing" & look at the chips in the oil coolant wash to determine if the bore was being accurately machined...

Bob Smith commented on his posting
Here is that monster in action. All nine guns firing full broadside at once. Rounds weigh 2,700 lb. Range of 24 miles. Accurate within a football field, & took out everything within that area.'
Rex Whinery I read one time firing all guns on one side like this shoved the ship 75 ft. I wonder if that was true.
Chance O'Neil No. The ship does not move by any noticeable amount. And the shots are not fired at exactly the same time. There is about a .05 second delay between each of the three guns on a turret. That prevents the shock wave of one round from interfering with the trajectory of the round from an adjacent barrel. The water is foaming due to the shock wave. The guns would still create massive shock and vibration in areas of the ship and that caused minor problems occasionally. My uncle was a fire control officer on the new Jersey and the Missouri so I got to learn a lot about those ships when I was growing up.

Bob Smith commented on his posting
16 " Rifling Head. The individual broaches were adjusted simultaneously. Each pass took .002" - .005" greater depth of cut than the previous. The head started at the muzzle & came out the breech. After it came out, the broaches were retracted & the head was pulled back. They were adjusted out another .002" - .005" for the next pass. Due to the amount of pressure, every other broach seat was left open. This meant that after the entire length of the liner was rifled to the specified depth, the head was indexed so the the remainder of the honed bore was rifled.
Bob Smith commented on his posting
Close up of the rifling head & broaches.
Bob Smith commented on his posting
Finished product.

1918 mounting of a 14" naval gun on an armored railway car.

A video of a modern gun drilling machine. Note that it is made in Taiwan. America geared up for WWII production by converting existing manufacturing plants and their skilled labor. We no longer have those plants and skills to convert to war production.

A video of a gun lathe in operation: tool cutting, measuring, grinding and boring.

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