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High Precision & Precision Lead Screws

Load - In order to properly incorporate a lead screw into a design, load requirements must be takeninto account. Maximum load values for the nuts are listed in the tables on the following pages. Thesenumbers are based on the shear of the nuts and does not take shaft buckling into account (see Max.Column Load formula below). Wherever possible, nuts should be positioned so as to be put intension, pulling the load. This eliminates the need for buckling considerations. Listed below are somehelpful formulas to assist in proper lead screw selection. Maximum Column Load (F) = K x C X 10
6 X d
4 /D
2 Where : K = End support factor.025 one end fixed, other free(Figure 9.1)1.00 simple supports both ends(Figure 9.2)2.00 one end fixed, one simple(Figure 9.3)4.00 both ends fixed(Figure 9.4)C = Material factor13.4 for Stainless Steel screws4.8 for Aluminum screwsd = Root diameter of the screwD = Length between the nut and the support bearingWhere

E

3

Torque to Move a Load (T) = (F x L) / (2 x π x E) : F = LoadL= LeadE = Efficiency (consult Berg Engineering Departmentfor efficiency values) Horsepower (HP) = Torque (in. lbs.) x RPM / 63,025
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