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Primary Material Selection Guide
Symmco Standard Bearing Materials

Material Overview Applications
Symmco: Sym 1
MPIF: CT-1000-K26
ASTM: B438-00a
Grade 1, Type 2
SAE 841 - Bronze
Standard high quality bearing material. Stocked in standard bearing sizes as well as bar and plate stock. Highly wear resistant, ductile and corrosion resistant. Business machines, lawn & garden, home appliances, conveyors, water pumps, industrial motors, tool & hobby, motion controls, hydraulics, farm machinery, mining equipment.
Symmco: Sym 77
MPIF: FC-2000-K25
ASTM: B 439; Grade 4
SAE 863
Iron-Copper
More economical than bronze. Moderately higher strength rating. Lower PV value. Stocked in cored and solid bar stock. Farm machinery, ATV's, pulleys, sheaves, wheel barings, machine tools
  • Symmco standard oil impregnated bearings are all ROHS compliant and manufactured at our facility in Sykesville, PA. Made in the USA.

PV Factor:
the normal load carrying capacity of a bearing material and is expressed as a factor (Pressure or bearing load in pounds per square inch x Surface Velocity as in feet per minute.)

Material PV Static P (PSI) Dynamic P (PSI) V (sfm)
Sym 1 50,000 8,000 2,000 1,200
Sym 77 35,000 20,000 4,000 225

Calculating the PV factor:

P = the load in (psi) on the bearing area (Bearing ID x Length)
V = surface velocity of the shaft in feet per minute (sfm)
PV = W/LD x pDS/12 = 3.14WS/12L
W = bearing load (pounds)
L = length of bearing (inches)
D = inside diameter of bearing (inches)
S = shaft speed (rpm)

The PV factor lists the working value upper limits and should not be exceeded. Exceeding the limits may cause premature failure of the bearing.
Symmco Incorporated | 40 South Park Street, PO Box F | Sykesville, PA 15865 | Phone: 814-894-2461 | Fax: 814-894-5272