Precision Trapezoidal Threaded Rods and Nuts - Maryland Metrics

Installation, maintenance and operationInstallation and maintenance oftrapezoidal thread drivesInstallation: Trapezoidal thread drives must be alignedcarefully during installation – if suitable measuringequipment is not available, the thread drive should beturned through its entire length by hand before the driveunit is attached. Variations in the amount of force requiredand/or marks on the external diameter of the spindleindicate alignment errors between the spindle axis andguide. In this case, the relevant mounting bolts should firstbe loosened and the thread drive should be turnedthrough by hand. If the amount of force required is notconstant throughout, the appropriate components shouldbe aligned, otherwise the alignment error should belocalized by loosening further mounting bolts.Cover: By virtue of their design, trapezoidal threaddrives are less sensitive to dirt than ball screw drives,particularly at low speeds (manual operation).Motor driven units, especially with plastic nuts,nonetheless require protection against dirt in the sameway as noted for ball thread drives.Oil lubrication: Used only in special cases fortrapezoidal thread drives.Grease lubrication: Grease is the usual lubricationmethod for trapezoidal thread drives. Lubrication intervalsare governed by operating conditions; it is advisable toclean the spindle before greasing. We do not recommendMolykote grease with graphite additives.Operating temperature: This depends on the type ofnut used, the lubrication conditions and the user’srequirements. Please consult us in the case oftemperatures above 100ºC (plastic nuts 70ºC).Wear: This can be checked manually: if the axialbacklash with a single-start screw drive is more than 1 /4of the pitch, the nut should be replaced immediately.copyright 2002, 2013 maryland metrics/precision technology usa, inc.