Big Complicated Machines

Big, Complicated Machines #9 – The “Fifty”

Preparing to add a die to the 50,000 ton forging press, the “Fifty”

Good morning everyone.

Today we’re going to take a look at an important piece of industrial history.

During WWII it was common practice for Allied intelligence teams to examine downed and captured German aircraft in order to determine how they were constructed and if there was anything that could benefit the Allied war effort. What they found was that the German aircraft contained very large, high quality structural elements, and it was determined that these elements had been produced on large forging and extrusion presses that were much larger than anything existing in the Allied nations. The implications of this were immediately apparent. If forgings and extrusions that were large enough and of high enough quality to become key structural elements in aircraft could be produced in this country, it would lower the time and costs of fabrication and boost aircraft production output. Make more bombers faster, in other words.

The U.S. immediately started a high-priority project to construct a large press that matched the estimated capabilities of the German machines, and contracts were awarded to the Mesta Machine Company of Pittsburgh to build an 18,000 ton press, and others for the production facilities. Just about every part of the construction process was new, including the necessity of building the plant around the press due to its enormous size. The project wasn’t completed however, due to the end of WWII.

When all of the shooting stopped, Allied technical teams went into the German factories and found that the Germans had produced and learned how to operate die forging presses up to 30,000 tons capacity, and found that one 30,000, and two 15,000 ton presses were still usable. As part of the post war settlement, the Soviets got the 30,000 ton press and the U.S. got the two 15,000 presses, which were channeled into the USAF’s Heavy Press Program.

The Heavy Press Program didn’t really get started until 1950, after many months of planning and getting input from the defense industry. Since there wasn’t a consumer market for anything produced by the heavy presses constructed by the program, the government would own the facilities and rent them out to the contractors. Thus, Air Force Plant 47 was authorized to be built in 1952, located in Cleveland, Ohio next to the ALCOA plant, to house the 50,000 ton press that Mesta was making. The plant began operation on May 5, 1955, and that’s when the “Fifty” went to work.

Image #1 – The Mesta 50,000 ton hydraulic closed die forging press

The Super Giant

The Mesta 50,000 ton “Super-Giant” forging press is big. Everything about it is big. The press, called the “Fifty” by those who work with it, is 87 feet high, 36 feet below ground level and 51 feet above, and weighs in at around 8,000 tons. (Image #1) Some of the largest castings required over 350 tons of steel for the pour, and eight other castings weigh from 215 to 240 tons apiece.

Image #2 – Machining a cast steel base section on a Mesta 18 inch horizontal boring and milling machine.

Image #3 – Milling an upper base section. Over 298 tons of steel was poured in the Mesta foundry to make this casting.

On top of the underground foundation assembly are two upper and two lower base sections (Image #2). The lower platen is attached to these, and the lower forging die is clamped to the 12 foot by 26 foot platen. The upper platen is attached to the lower moving crosshead (Image #3), and with no dies on the upper or lower platens, there is 15 feet of clearance. Since the maximum stroke of the press is six feet, the forging dies it uses must be fairly large, to say the least. The entire moving crosshead assembly consists of eight steel castings that total nearly 1150 tons (Image #4).

Image #4 – An upper moving crosshead section cast from 657 tons of steel in the Mesta foundry.

Image #5 – Checking a pressure cylinder port in one of the stationary crossheads with a micrometer.

Image #6 – A Stationary crosshead.

Above the moving crosshead assemblies are the stationary crossheads (Images 5 & 6) that house the eight main hydraulic pressure cylinders. (Image 7)

Image #7 – Finishing one of the eight forged alloy steel pressure cylinders on a Mesta 110 inch turning and boring lathe. Each cylinder was machined to an inside diameter of 5 feet 1/2 inch and 11 feet 7-1/2 inch.

Image #8 – One of the eight alloy steel columns forged from a 270 ton ingot on a Mesta hydraulic forging press.

Running through the press from top to bottom are eight massive alloy steel columns 76 feet long and 40 inches in diameter. The columns were forged from 270 ton steel ingots and machined on a 96 inch lathe. Each column was trepanned to remove an eight inch diameter core the full length of the column (Image 9). Four sections of each column were threaded and fitted with four steel nuts, each 52 inches in diameter, with eight of the largest nuts weighing 55 tons each. (Hey Louie, pass me the 51 and 13/16″ socket, wouldja?) Like I said, everything about this machine is big.

Image #9 – Turning and trepanning a 10 inch diameter hole through one of the press columns on a Mesta 96 inch turning and boring lathe. The eight columns were finished to 40 inch diameter by 76 feet long.

Image #10 – The hydro-pneumatic pressure system contains four accumulator bottles maintaining a pressure of 4,500 pounds per square inch. Each pressure bottle was forged in one piece by Mesta from a 195 ton alloy steel ingot.

The press uses a hydro-pneumatic pressure system to generate it press force, using water with soluble oil as the working fluid. 1,500 hp motors charge four forged steel accumulators (Image 10) to 4,500 psi each, which is then released to the eight pressure cylinders mounted in the stationary crosshead at the top of the press. The combined effort of these eight cylinders produces 50,000 tons of force between the platens.

50,000 tons. I’ve used that number a lot talking about this big freaking press, but just how much is 50,000 tons, in something that you can visualize? Well, let’s see; the platens that hold the forging dies are 12 feet wide by 26 feet long, if you recall. If you had a steel bar that was 12 feet by 26 feet and 612 feet long, and stood it on its end on the lower platen of the press, that would be 50,000 tons of pressing force. My, my, what a vision.

At the end of the press cycle, the hydraulic force is reversed and the fluid is directed into eight pull-back and balancing cylinders that return the moving crosshead back to its starting position.

Image #11 – Lowering the massive stationary crossheads into position over eight pressure cylinders and eight columns.

The “Fifty” was shut down in the summer of 2008 when engineers found stress cracks in the machine’s base. Much hemming and hawing was done by ALCOA, the operator of the press, on whether to rebuild or scrap the machine, as it was estimated that it would cost $68 million dollars to rebuild it. Pressure was applied by Senators and CongressCritters,  as well as local government and unions, to fix it and preserve around 1,000 jobs. In 2009, ALCOA decided to rebuild the press after wringing out concessions and incentives from the interested parties, and it has just recently resumed operation. Which is a good thing, as most aircraft flying today have structural elements that were made on the “Fifty” before it broke down. Parts were made on the “Fifty” for the Space Shuttle when it was flying.  While the big machine was down, a smaller 35,000 ton press was used as a backup, but it wasn’t an “ideal solution”, according to the operating company. Parts for the F-35 will be made on the big press, as well many other fighter and commercial aircraft. They expect to get another 50 years of service from the machine. Maybe I should have them take a look at my knees….

Many thanks and a huzzah! to jeepjeff for bringing this wonderful machine to my attention.

If you come across something that you think is of interest to our eclectic group of readers (and the dim-bulbs too. We’re nothing if not fair), submit your something to


The American Society of Mechanical Engineers – 50,000 Ton Closed Die Forging Press

The Library of Congress – Historic American Buildings Survey/Historic American Engineering Record

BoingBoing – Bringing a 50,000-ton forging press back to Life

The Atlantic – Iron Giant – Huge Mesta press is backbone of Alcoa’s Cleveland Works – Alcoa to rebuild 50,000-ton press in Cuyahoga Heights plant

  • The sound that must make when the top die hits the material…

    Also, don't break an alignment pin.

  • jeepjeff

    Next time I am in Ohio, I am taking a side trip to Cleveland just to see this. I normally wind up in Cincinnati, OH, as that's where my Dad's family lives, so it's a 250 mile drive, but it looks totally worth it.

  • B72

    We use this one press to make most of our airplanes, and there is only one of them? Given that air superiority is a key element of our defense strategy, this sounds like a national security risk. We should build another big press!

    • jeepjeff

      We have eight big presses, this is just the biggest. Also, my understanding is that we don't have enough production to justify a second one.

      • B72

        The sense of the article was that the second biggest was a 35, and that it was a poor substitute, no?

        • The Professor

          The 35,000 ton press was the second largest press at that factory. The impression that the 35k ton press wasn't up to snuff was a comment in one of the articles made by a couple of employees of the plant. They didn't specify what the problem was, but I imagine that it doesn't generate sufficient pressure.
          While researching this article I came across a mention of an 88,000 ton press that we have somewhere. I'll have to see if I can find more info about it.

      • The Professor

        There's at least one other 50,000 ton press out there, the Wyman-Gordon press in Grafton, Mass. Here's some info:
        I'm not sure of the current status of the machine.

  • B72

    In my younger days I had the opportunity to watch a 200 ton press work. The platen was similarly large, and the operator had to climb into the jaws of the press to take the parts in & out. The scariest bit was that the jaws would slowly close while he was in there, until it hit a limit switch and activated the hydraulics to open them up again.

    I decided I didn't want that job.

    • pj134

      At least it probably wouldn't hurt if the switch broke…

      • FЯeeMan

        Yes, but the job of wringing you out of the sponge for your grieving spouse wouldn't be a fun one.

  • FЯeeMan

    Does this press reside in the building that also houses the machinery that build the pieces for it? I can't imagine moving a 657 ton upper moving crosshead section too far from its point of origin.

    Hey, let's build a 50,000 ton press!
    OK, get to work designing it
    Hey, we'll need a 35,000 ton press to make some of the parts.
    Dang. We don't have one of those. Get to work designing one!
    Hey, we'll need a 15,000 ton press to make the 35…
    Um… I've got this 20lb sledge, what can we make with that?

    • The Professor

      No, the press was cast and machined at the Mesta Foundry:
      "Sixteen huge steel castings poured in the Mesta foundries at West Homestead, Pennsylvania comprise the major elements of the press. Over 350 tons of steel were required to pour some of the largest castings; that is enough steel to supply the needs for 200 passenger cars. There were eight other castings weighing between 215 to 240 tons each. Equipment used to machine the press sections included a Mesta 18 inch horizontal boring and milling machine designed and built especially for the job."
      Everything was shipped via railcar.

  • Truth

    This press needs it's own special on TV.

  • Pingback: Mesta Memories #24: Steam-Hydraulic Forging Presses : Atomic Toasters()