Why Does Steinmeyer Rarely Make a Ball Screw by Cutting an Existing Shaft?

Some manufacturers of ground ball screws produce long threaded shafts in quantity and then cut them down as needed to make shorter units.  This is not our normal business model.  Steinmeyer will do that on very rare occasions to save some time but only if the quantity desired is one or two pieces, and of course provided the longer shaft is available.  Why?The main reason is that once the shaft is cut, the center reference hole is lost – and it’s the center hole that we use as our machining reference for all critical dimensional runout tolerances including the ball groove.  The result of such a “modified” unit is a higher runout of the ball nut as it travels down the shaft, which if it’s a minor variation above tolerance will cause somewhat higher heating and additional wear but if it’s more than minor could result in a binding condition, and more serious damage.  Another reason of course is cost since most customers typically only want to pay for the shorter ball screw, and not the higher cost because a longer shaft has been consumed.  So, feel free to ask the next time you contact us regarding quicker delivery on a ground ball screw but don’t be surprised if we say we cannot accommodate your request.

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