When close dimensional tolerances are required…

The straightening process consists of using a hydraulic press to “punch” a cylindrical shaped part in specific areas to restore straightness to a specified tolerance. It may also include the use of heat, typically via a tempering oven that heats the parts to a set temperature to relieve any residual stresses that may be present in the microstructure of the material. After the stresses are relieved, parts are again placed into a hydraulic press to “punch” them at various points and put them back into tolerance. The heat and “punch” cycle may need to be repeated several times before the part is restored to the specified tolerance. The straightening process must be completed by a highly trained and skilled operator, generally with many years experience straightening parts.

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  • Corrects any distortion caused by either high temperature processing or subsequent quenching operations.
  • Straightness runout of thousandths of inches over the length of the part can be achieved.
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  • Amount of processing time (charged by the hour) is solely dependent upon the various stresses in the material, making time and cost relatively unpredictable.
  • Risk of cracking if straightening process is not properly performed.

Equipment Used

  • Straightening presses.
  • Dimensions vary by press.

Materials (Alloys) Treated

Any alloy represented as a bar or cylindrical shape.


Typically any long, cylindrical shaped part, such as bar stock.


Automotive, power generation, firearms, and any other that requires extremely tight dimensional tolerance.


Typically given in Total Indicator Runout (T.I.R.) which is an indication of straightness according to a specified length and allowable distortion from diameter.

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Need Machining as well?

Our sister company, TMD Machining, is a precision machine shop, so much so, that they specialize in aerospace solenoid valves. If you’re looking for a high quality machine shop, check out TMD.