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Another Flatness Tip  

Another Straightness Tip

   Consider Straightness on Your Parts Made from Flat Stock. 

Many parts are made from stock which is left in the as furnished condition. Rule #1 does not apply to the thickness of these parts. Therefore, the form variation of the part is whatever the mill supplies. Many designers will control the form of such parts with flatness. Flatness is often a very time consuming inspection. When straightness at MMC is applied to the material thickness, a simple envelope gage at the virtual condition may be used to limit form variation. In this example, the envelope gage used to verify straightness would measure 1.025. The actual local size of this part must be checked with a micrometer type measurement to assure that, at any cross section, the thickness is between .995 and 1.005.

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