SHIELDED LEADSCREWS WITH PRE-LOADED NUTS

Another feature pioneered by us in 1986, all our leadscrews are of the acme thread form and are 10 TPI ( Threads Per Inch). Other imported machines use a metric screw and then compensate with a dial graduated in an odd number of inch markings.  Our leadscrews are fully shielded which is one of the reasons our machines retain their accuracy far longer than the competition.  Machining creates chips and particles, which when mixed with cutting fluid create an abrasive paste.  If this is allowed to flow onto your leadscrews, you will begin getting wear and inaccuracy almost immediately.  On the PATRIOT machines, all of the leadscrews are 100% covered to prevent this.  In addition we have the exclusive double pre-loaded lead screw nuts to keep your machine adjusted for minimum backlash throughout its life.  Most machines use a single brass nut, which due to the manufacturing process will have from 0.008-0.0012" back lash in order to turn freely on the screw.  SHOPMASTER designed our system with 2 brass nuts with a special double bracket and one nut with an adjustment flange, which allows the clearance necessary in the manufacturing process, but puts load against the leading and trailing edges of the screw to reduce the lash to the 0.002-0.004" range.  this lash can actually be reduced to zero, but will result in high friction on the screw.