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WW2 ERA New Departure precision ball bearing display promo card with bearings
WW2 ERA New Departure precision ball bearing display promo card with bearings
WW2 ERA New Departure precision ball bearing display promo card with bearings

WW2 ERA New Departure precision ball bearing display promo card with bearings

$ 21.12

Availability: 82 in stock
  • Conflict: WW II (1939-45)
  • Region of Origin: United States
  • Original/Reproduction: Original
  • Theme: Militaria
  • Country/Region of Manufacture: United States
  • Modified Item: No
  • Condition: It appears that bearings may have been originally taped in place as issued. Tape has darkened and is separated, but present on front side.

    Description

    WW2 ERA New Departure precision ball bearing display promo card with bearings
    These two tiny bearings are used in delicate aircraft instruments such as fuel and manifold pressure gages, turn and bank indicators and artificial horizon. They provide extreme sensitivity without the danger of vibration cracking which is possible with jewels.
    Bearing No. C-270 at the left is the smallest ball bearing made in America. It's outside diameter is 2.7 millimeters (.1063") and it has three 1-millimeter (.03937") balls.
    Bearing No. PF-4 at right has an O.D. of 4 millimeters and six 1 millimeter balls.
    In spite of their tiny proportions, both bearings are equipped with separators.
    Flat 3.00 USPS First class shipping within continental US only.
    Please see my other items currently for sale, will combine shipping.