Ball Screw Repair

There are millions of Steinmeyer ball screws in use today and we are often asked “does Steinmeyer offer repair services for ball screws?”  And the answer is yes, for very limited situations.  However we are aware that many ball screw users routinely get screws repaired at companies whose main business is repair – and one has to be very careful about what to expect of such a repair. The reason is simple – a properly designed and applied ball screw has an expected life.  Should the ball screw fail prematurely the reason should be determined prior to merely replacing the screw – otherwise the very same thing will happen again, namely premature failure.  Steinmeyer will inspect and evaluate any Steinmeyer product that is returned – and provide a report of our findings.  The cost for this depends on the desired detail in the report.  Unlike other so-called ball screw repair facilities, we do not believe a used ball screw can be “repaired” – that is fitted with larger balls to make up for the wear from usage, or re-grinding the ball groove thread surface in the shaft or nut or both.  Why?  Because the races as well as the balls are subject to material fatigue. While balls can be easily replaced, there is no way to remove prior exposure to the pulsating load of balls passing over any given spot in the raceways of nut and shaft. Re-grinding is not going to remove this, because the depth of the fatigue stresses is greater than the allowable material removal.  Therefore we would not be able to support such a “repair” with a credible warranty.  We also do not think much of repair facilities that re-ball worn screws with oversized balls – all this does is restore some basic functionality but who knows for how long?

We routinely do provide repair services for our ball screws for the following occurrences:
1. the user has inadvertently run the ball nut off the thread and, to his dismay, some or all the balls inside the nut came out – rendering the ball screw inoperative.  NB: if this has occurred, we strongly caution against trying to re-install the balls – you will most likely insert the balls in the wrong place in the nut.  Better to contact us so we can restore the ball nut properly.
2. a wiper on the ball nut has been dislodged or damaged as a result of contacting a hard stop.  Wiper replacement is fairly straightforward and can often be done in the field.  If the ball nut must be removed in order to gain access to the wiper on one end, Steinmeyer can provide the dimensions of an appropriately sized mandrel necessary to safely remove the nut from the shaft without the balls falling out.

In all other cases, and if you need an operable ball screw urgently and cannot get a new one in a timely manner, we will assess the situation and determine if an emergency repair is possible or not. But in any event, you should first try to get a new ball screw, because even if we manage to restore the functionality of the damaged one, you will need it soon.

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