Slide mounting
Drawings at the right show the most common mounting positions of hardened steel way slides. When slides are mounted other than horizontal, the load capacity changes and in some cases lubrication holes and grooves have to be altered. Be sure and specify if mounting is other than horizontal when ordering.

Slide loading
This data should be used as a guide to determine the size of a slide for a particular application. All values are for uniformly distributed loads and moments, and the saddle is assumed to be a rigid member. Some conditions may allow the use of higher load values (e.g. rough machining or positioning applications), while other conditions dictate the use of lower values (e.g. precision boring or grinding applications). For saddle lengths longer than two times the width, and if deflections are critical, please consult factory for load capacity.

Maximum load &
moment calculations

Maximum loads:
L_D max.= D x SL (lbs.)
L_U max. = U x SL (lbs.)
L_S max. = S x SL (lbs.)
Maximum moments:
M_W max. = W x SL (in. lbs.)
M_T max. = T x (SL)² (in. lbs.)
M_L max. = L x (SL)² (in. lbs.)

Definitions
Slide loading

A = Slide width (inches)
D = Down load factor
L_D = Vertical load down (lbs.)
L_S = Horizontal load side (lbs.)
L_U = Vertical load up (lbs.)
L = Length moment load factor
M_L = Moment about saddle length (in. lbs.)
M_T = Moment about plane of saddle top (in. lbs.)
M_W = Moment about saddle width (in. lbs.)
P = Load producing moment (lbs.)
S = Side load factor
T = Top moment load factor
U = Up load factor
W = Width moment load factor
X = Distance from load P to slide way (inches)
Y = Distance from load P to slide way (inches)
Z = Distance from load P to center line of slide (inches)
SL = Saddle length engaged on base (inches)

Slide thrust and torque

The force required to power the slide assembly (F_H and F_V), includes the force to overcome all external loads as shown under "slide loading," plus the force required to power the saddle assembly times a factor of safety. The factor of safety is applied to ensure sufficient power to accelerate the load and overcome friction due to variables such as lubrication, machining tolerances, finish, etc.

Depending on the type of drive used, see FS under definitions below.

The torque required to accelerate or decelerate the slide is dependent upon the moving weight, screw size, the force applied to the slide and the rate of acceleration or deceleration. Please consult the motor manufacturer you selected for this analysis.

The thrust values obtained from the calculation must be checked against the maximum thrust capacities (see the Hardened way slide catalog 3.08 MB), for the drive model being used. If acceleration time is critical or speeds above 350 ipm are required, please consult factory for power requirements.

Thrust and torque calculations
Thrust calculations ± :

F_H = (F_D + F_SLH + F_L + F_ML + F_MW + F_MT)FS
F_V = (F_D + F_SLV + F_L + F_ML + F_MW + F_MT)FS

F_SLH = (µ)(W_SL)(SL)
F_SLV = (W_SL)(SL)
F_L = (µ)(L_D + L_U + L_S)
F_ML = (3µ)(M_L/SL) + P
F_MW = (2µ)( M_W/E ) + (µ) (P)
F_MT = (3µ)( M_T/SL ) + P

Torque calculations:

T_H = T_D + (K)(F_H)(L)
T_V = T_D + (K)(F_V)(L)

± All forces, loads and moments must be added using correct signs positive or negative

Definitions
Slide thrust and torque

F_H = Force required to power slide horizontally (lbs.)
F_V = Force required to power slide vertically (lbs.)
F_D = Force required to overcome saddle drag (lbs.)
10 lbs. — 100 lbs.
Drag force is affected by several factors including
gib adjustment, way wipers, way covers,
lubrication and slide size. Use lower values for
smaller slides and higher values for larger slides.
F_SLH = Force to power saddle weight horizontally (lbs.)
F_SLV = Force to power saddle weight vertically (lbs.)
F_L = Force to overcome loads L_D, L_U, L_S (lbs.)
F_ML = Force to overcome moment M_L, and load P (lbs.)
F_MW = Force to overcome moment M_W, and load P (lbs.)
F_MT = Force to overcome moment M_T, and load P (lbs.)
FS = Factor of safety
Manual drives = 1.5
Lead screw drives = 2
Hydraulic cylinder drives = 2.5
Air cylinder drives = 3
µ = Coefficient of friction with lubrication
.25 cast iron on hardened steel
.08 Low friction bearing material
SL = Saddle length (inches)
W_SL = Weight of saddle (lbs./in.)
E = Distance across ways (inches)
Download catalog for dimension. (3.08 MB)
T_H = Torque to power slide horizontally (in. lbs.)
T_V = Torque to power slide vertically (in. lbs.)
T_D = Torque to overcome drag of screw assembly
See chart. (in. lbs.)
K = Screw constant
.64 Acme screw
.20 Ball screw
L = Lead of screw (inches per rev.)
Download catalog for dimension. (3.08 MB)