The Pressure Cabin

  Based on Auguste Piccard's Original

The XAP cabin, often called the Gondola, will be produced by the Acme Metal Spinning Company of Minneapolis, Minnesota, builders of the U.S. Navy Stratolab cabin for Jean Piccard and the four foot cabin for Don Piccard's "Golden Bear" record balloon - winner of the State of California Gold Medal.
Material below is courtesy
of Acme Metal Spinning &

The Johnston Family.



Acme Metal Spinning Produces 6 Foot Diameter
Stainless Steel Hemispherical Parts

Acme Metal Spinning, a well-known 88 year old metal spinning company, successfully achieved production of four identical, 72" diameter, one-piece design hemispherical parts.

Acme designed and produced a laminated wood tooling pattern (a common technique used in the metal spinning industry) for production of the hemispherical parts. The tooling was designed on Acme's CAD system and then machined on a 140" diameter capacity lathe.

Production of the parts started out with 3/16" thick, type 304 stainless steel blanks measuring almost 8 feet in diameter. The parts were produced on a specially equipped hydraulic spinning lathe customized by Acme to enhance part size and overall finish quality.

The four parts measured 72" in diameter x 36" deep. Acme used an annealing process during the production to help relieve material stress and work hardening. Finally, the parts were polished to a #4 finish.

Acme is considered a specialist in hemispherical and large diameter spinnings. Secondary value-added operations can be easily incorporated on one of Acme's additional CNC systems.

Other common industries using components produced by Acme include:

  • air-moving
  • cryogenic tank building
  • food processing
  • agricultural
  • architectural.

If your requirements are as small as .50" in diameter or as thick as 3/4" in mild steel, Acme is your one-stop-source in metal spinnings.


The gentleman in the Top picture is Acme's technician, Rick McCoy.



The picture below, from 1960, shows ( L to R) Henry Johnston, Pres., Prof. Jean Piccard, Lloyd Johnston and Don Piccard with the four foot diameter spun aluminum cabin for the "Golden Bear" record setting balloon.   Lloyd's brother Tom is the current President and Lloyd has retired.

The Acme Metal Spinning Company cabin used for the U. S. Navy's "Stratolab" program was welded from eight spherical right triangles, thereby having no (stress raising) "Tee" weld joints.  In 1960, four foot diameter was Acme's largest diameter spinning capability.  The Golden Bear cabin was assembled with equatorial spun flanges joined with Mil Spec aircraft nuts and bolts.

A reclining formed foam seat provided a comfortable pilot cockpit for six foot two inch Piccard in 1960.   XAP will use  Acme's current ability to make a more spacious five foot sphere from two halves.  XAP has considerably greater requirements for on board life support apparatus and flight  instrumentation.  The hatch will, once again, be at the top pole of the cabin for convenient "open basket" hot air balloon piloting technique at low altitudes for the final stages of the expedition.

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