How Big is 5 Thousandths


How big is .005 Inch?  In everyday life it is very small.  In astronomic and geologic terms the moon moves further from the earth by .004 inches and North America moves .002 inches further from Europe each day.  Your fingernails grow at a daily rate of approximately .004 inch.

As people relate to things more readily than numbers here are the approximate sizes of some common items:

  • Human hair:                        .004” Diameter
  • Coat of Paint:                      .005” Thick
  • Poster Board:                      .010” Thick
  • Fingernail:                           .015” Thick
  • Baseball Card:                    .020” Thick
  • Credit Card:                        .030” Thick
  • Paper clip wire:                   .040” Diameter
  • US Dime:                            .045” Thick
  • Compact Disk:                    .047” Thick
  • US Penny:                          .060” Thick
  • Pencil lead:                         .080” Diameter
  • 6D Penny nail:                    .120” Diameter

Applying the sizes of these common objects to the Investment Casting Institute’s “Linear Tolerance Table it might look something like this:

Dimension          Normal Tolerance                    Equivalent Tolerance

  • Up to 1”                ±.010”                   or            ± Two Human Hairs
  • Up to 2”                ±.013”                   or            ± Human Fingernail
  • Up to 3”                ±.016”                   or            ± Human Hair + Human Fingernail
  • Up to 4”                ±.019”                   or            ± Baseball Card
  • Up to 5”                ±.022”                   or            ± Baseball Card + Human Hair
  • Up to 6”                ±.025”                   or            ± Baseball Card + Coat of Paint
  • Up to 7”                ±.028”                   or            ± Baseball Card + Poster Board
  • Up to 8”                ±.031”                   or            ± Credit Card
  • Up to 9”                ±.034”                   or            ± Credit Card + Human Hair
  • Up to 10”             ±.037”                   or             ± Paper Clip

In the world of cast products these are amazingly tight tolerances especially when you consider that Investment Castings are manufactured without the need of a draft allowance.  Admittedly some finish machining of critical surfaces will still be necessary, however, the near-net-shape capability of Investment Casting works to minimize the number of surfaces that will need to be finished.

Not only is Investment Casting a highly accurate metalcasting process but its ability to cast complex shapes and combine multiple components into a single unitized structure is a highly effective method to reduce the part count of an engineered assembly.

If you have interest in employing the benefits of the Investment Casting process, O’Fallon Casting offers a Concurrent Engineering Service to assist its customers to optimize their cast configurations.  If you ‘d like to know more about Investment Casting or are interested in Concurrent Engineering, please call O’Fallon Casting and speak with one of our Sales Engineers.