- Gears, Differentials, Racks & Pinions
- Synchronous Drive Belts, Pulleys, & Cables
- Couplings, Flexible Shafts, & Universal Joints
- Chains & Sprockets
- Shafts & Shaft Accessories
- Bearings & Linear Motion Components
- Motors, Gearheads, & Motion Control
- Speed Reducers & Right Angle Drives
- Hardware
- Miscellaneous Components
- Linear Guide Systems
- Clutches & Brakes
- Vibration & Shock Mounts
Ball Bearing Lubrication and Surface Finishes
1.9 Lubrication and Surface Finishes
Rolling contact bearings have to be lubricated in addition to having exceedingly good surface
finishes.
The life of a rolling element bearing depends to a large extent on the smoothness of the
contacting surfaces – the balls, rollers, and races. Typical surface roughness dimensions for
production bearings are as follows:
Balls 2– 3 μin rms
Ball races 6–10 μin rms
Rollers 8–12 μin rms
Roller races 10–20 μin rms
These are in terms of microinches or millionths of an inch, usually written μin. The unit of measurement of the surface roughness is rms which stands for "root-mean-square
height". This value is obtained by drawing a diamond point instrument over the surface with a
magnified readout. These measurements are taken at equidistant points on the profile, squaring
these values, adding them, dividing the sum by the number of readings taken and taking the
square root of this average.
There are calibrated specimens available and surface roughness can be established by comparison to the specimen.
Surface finishes of bearings vary considerably from manufacturer to manufacturer. They are
usually not given specifically for each product.
As far as lubrication is concerned, in general, the application environment will usually dictate
the proper lube required. Today's lubrication selection has varied greatly over the past few years.
Modern methods of mixing, compounding and blending various additives and bases has become
a very exact science, a far cry from late 1940 when almost all lubricants were a refined petroleum
products.
Operational conditions such as temperature, loads, speed, environment and torque available,
will determine what type should be used – oil, grease or dry films. Oil fluid is the base lubricant
for nearly all bearings, whereas grease is an oil that has been thickened. The use of lubrication
will reduce friction and wear, prevent corrosion or oxidation and help to prevent heat buildup
within the bearing. Other benefits that result from proper lubrication are quietness, lower torque
and extended life. Lubrication selection is very important to good bearing performance. The
following tables of lubrications shown are the most widely used by bearing users today. Due to
the constant change of product demand and scientific technology, we recommend that an SDP/SI
engineer be consulted if you cannot locate a suitable lubrication in the following charts.
SDP/SI supplies bearings with an oil lubrication meeting military specifications (MIL-L-6085A), grease meeting (MIL-G-23827A), or Beacon 325 commercial grease. Other lubricants available on special order.
These are in terms of microinches or millionths of an inch, usually written μin. The unit of measurement of the surface roughness is rms which stands for "root-mean-square
height". This value is obtained by drawing a diamond point instrument over the surface with a
magnified readout. These measurements are taken at equidistant points on the profile, squaring
these values, adding them, dividing the sum by the number of readings taken and taking the
square root of this average.
There are calibrated specimens available and surface roughness can be established by comparison to the specimen.
Surface finishes of bearings vary considerably from manufacturer to manufacturer. They are
usually not given specifically for each product.
As far as lubrication is concerned, in general, the application environment will usually dictate
the proper lube required. Today's lubrication selection has varied greatly over the past few years.
Modern methods of mixing, compounding and blending various additives and bases has become
a very exact science, a far cry from late 1940 when almost all lubricants were a refined petroleum
products.
Operational conditions such as temperature, loads, speed, environment and torque available,
will determine what type should be used – oil, grease or dry films. Oil fluid is the base lubricant
for nearly all bearings, whereas grease is an oil that has been thickened. The use of lubrication
will reduce friction and wear, prevent corrosion or oxidation and help to prevent heat buildup
within the bearing. Other benefits that result from proper lubrication are quietness, lower torque
and extended life. Lubrication selection is very important to good bearing performance. The
following tables of lubrications shown are the most widely used by bearing users today. Due to
the constant change of product demand and scientific technology, we recommend that an SDP/SI
engineer be consulted if you cannot locate a suitable lubrication in the following charts.
SDP/SI supplies bearings with an oil lubrication meeting military specifications (MIL-L-6085A), grease meeting (MIL-G-23827A), or Beacon 325 commercial grease. Other lubricants available on special order.
Brand Name | Basic Type Oil | Operating Temperature °F | Uses |
*WIndsor L245X (MIL -PRF-6085) |
Synthetic oil | -65 to +300 | Light general purpose instrument oil |
DuPont Krytox 143 AC |
Fluorinated oil | -30 to +550 | High temperature stability with good lubricity properties |
AeroShell #7 (MIL-PRF-23827C) |
Diester | -100 to +300 | Wide temperature range; good general purpose grease |
Texaco Low Temp EP (MIL-PRF-23827C) |
Synthetic Ester | -65 to +250 | Low torque at cold temperature |
*Exxon Beacon 325 | Synthetic grease | -65 to +250 | General purpose grease |
*Exxon Andok C | Channeling petroleum grease | -20 to +250 | Smooth running, long life with minimum migration |
Toray SH44M | Silicone grease | -25 to +350 | Higher temperature stability |
*Mobil 28 (MIL-PRF-81322) |
Synthetic hydrocarbon | -65 to +350 | Wide temperature range, good low temperature torque, general purpose |
Multemp PS No. 2 | Petroleum grease | -60 to +250 | Low torque, general purpose grease |
Chevron SRI-2 | Mineral grease | -20 to +350 | High speed, high load grease |
*Shell Alvania X2 | Mineral grease | -30 to +250 | Long life |
DuPont Krytox 240AC (MIL-PRF-27617) |
Fluorinated grease | -30 to +550 | High temperature stability with good lubricity properties |
KYODO SRL | Synthetic grease | -40 to +300 | Low noise and low torque applications |
NIG-ACE W | Synthetic grease | 0 to +300 | Low noise and low torque applications |
Isoflex J 032R | Synthetic grease | -60 to +250 | High speed, low torque grease |
U-1494 | Synthetic grease | -40 to +350 | High speed, high load applications |
Table 1-11 Oil Lubricant Available on Special Order
Manufacturer & Trade Name | Mil. Spec |
Operating Temp. Range, °F | Type | Pouring Point, °F | Flash Point, °F | Viscosity CS 75 °F / 210 °F |
Anderson Oil Company | ||||||
LS252 | MIL-17353A | -65/250 | Diester | -75 | 340 | 7.6/1.9 |
Bendix Corp. | ||||||
P10 | MIL-L-6085A | -70/350 | Diester | -80 | 420 | 23.4/3.8 |
Bray Oil Co. | ||||||
NPT3A 885 NPT9 |
MIL-L-6085 | -65/175 -50/400 -30/350 |
Diester Diester Ester |
-90 -85 -50 |
400 410 495 |
19/ 3.5 1875/ 9 710/55 |
Dow Corning | ||||||
DC200 DC510 DC550 FS1265 |
VVL1078 MIL-L-27694 |
-40/550 -70/500 -40/450 -50/300 |
Silicone Silicone Silicone Silicone |
-50 -80 -50 -30 |
600 600 600 500 |
Various Various 125/20 Various |
DuPont, E.I. | ||||||
Krytox 143 AB | -45 / 450 | Perfluor | -45 | 500 | 85/10.3 | |
Exxon Corporation | ||||||
P15A Aviation Inst. Oil Univis P12 Univis P38 |
MIL-L-7808 MIL-L-7870 MIL-L-6085A MIL-L-6085 |
-65/300 -65/290 -75/300 -65/300 |
Diester Petroleum Diester Diester |
-75 -70 -90 -70 |
450 300 410 415 |
22/3.5 17/2.6 30/3.6 72/37 |
General Electric | ||||||
Versilube F44 Versilube F50 Versilube SF81 Versilube SF96 |
MIL-S-81087 | -100/500 -100/400 -40/400 -40/400 |
Silicone | -100 -100 -55 -50 |
550 550 600 600 |
70/15 75/22 Various 40/16.5 |
Gulf Oil Company | ||||||
Synthetic Fluid #6 | -50/275 | Mineral | -90 | 295 | 3200/12 | |
Houghton Oil | ||||||
Cosmolube 270A | MIL-L-6085A | -65/250 | Diester | -70 | 365 | 15/3.5 |
Mobil Oil | ||||||
SHC824 XRL743A |
-50/350 -50/350 |
Synthetic Synthetic |
-65 -65 |
455 520 |
100/6.5 100/6.5 |
|
MPS Corporation | ||||||
MO119 | -30/250 | Synthetic | -80 | 455 | 119 @ 100°F | |
Shell Oil Company | ||||||
Aeroshell #3 Aeroshell #12 Aeroshell #4 |
MIL-L-7870 MIL-L-6085A MIL-H-5606 |
-70/240 -70/300 -70/500 |
Petroleum Diester Petroleum |
-75 -70 -85 |
275 365 215 |
16.5/2.3 21.5/3.5 859/10.4 |
Tenneco Chemical | ||||||
Anderol L401D Anderol L423 |
MIL-L-6085A | -75/260 -80/350 |
Diester Synthetic |
-80 -100 |
430 370 |
19.7/3.4 200/5.1 |
Table 1-12 Greases Available on Special Order
Manufacturer & Trade Name | Mil. Spec |
Operating Temp. Range, °F | Base Oil | Thickener | Color |
American Oil Company | |||||
Rykon Premium #2 Rykon Premium #3 Supermil ASU31052 Supermil ASU72832 |
MIL-G-25013 MIL-G-23827A |
-10/200 -20/250 -100/450 -100/250 |
Mineral Mineral Silicone Diester |
Arylurea Arylurea Arylurea Lithium |
Reddish Pink Lavender Amber |
Bray Oil Company | |||||
Braycote 627S Braycote 637S 601 |
MIL-G-23827 MIL-G-25537 |
-100/300 -65/260 -100/390 |
Ester Mineral Polyether |
Organic Calcium Soap Tetrafluor |
Lt. Brown Lt. Brown Off White |
Chevron Oil Company | |||||
BRB-2 OHT NRR335 |
MIL-G-3545C | -20/350 +20/300 -65/300 |
Mineral Mineral Synthetic Aeromatic |
Polyurea Sodium Sodium |
Blue Green Greenish Maroon |
Dow Corning | |||||
Molykote BR2 Plus Molykote 33 Molykote 41 Molykote 44 Molykote 55M |
MIL-G-46886A MIL-G-4343 |
-20/300 -100/350 0/550 -100/400 -65/350 |
Mineral Silicone Silicone Silicone Silicone |
Lithium Lithium Lithium Lithium Lithium |
Black Gray Black Dark Amber Tan |
DuPont, E.I. | |||||
Krytox 240AA Krytox 240AB Krytox 240AZ Krytox 240AC |
MIL-G-27617 MIL-G-27617 MIL-G-27617 MIL-G-27617 |
-30/450 -30/450 -65/300 -30/550 |
Fluor Carbon Fluor Carbon Fluor Carbon Perfluor |
Vidax Vidax Vidax Tetrafluor |
White White White White |
Exxon Corporation | |||||
Andok B Andok 260 |
MIL-G-18709A MIL-G-3545C |
-20/250 -20/250 |
Mineral Mineral |
Sodium Sodium |
Brown Amber |
General Electric | |||||
Versilube G351 | MIL-L-15719A | -40/400 | Silicone | Lithium | Cream |
Houghton E. F. | |||||
Cosmolube 615 | MIL-L-4343 | -65/375 | Silicone | Lithium | Lt. Brown |
Kyodo Yushi | |||||
PS #2 | -60/230 | Diester | Lithium | White | |
Mobil Oil | |||||
BRB #23 Mobil 24 Mobil 27 |
MIL-L-7711 MIL-G-25013 MIL-G-23827 |
-0/250 -100/550 -65/325 |
Petroleum Silicone Carbon |
Sodium Organic Non Soap |
Tan Reddish Tan |
NYE Rheolube | |||||
703A 716B 781D 899RP 2000 Rheo Temp 500 |
MIL-G-3278A | -30/250 -60/300 -95/390 -130/480 -60/260 -65/350 |
Mineral Polyol Ester Silicone Fluorether Hydrocarbon Diester |
Sodium Lithium Lithium PTFE Organic Sodium |
Tan Tan Off White White Red Blue |
Royal Lubricant | |||||
Royco 13D Royco 21 Royco 22MS Royco 27A Royco 37 Royco 64C |
MIL-G-25013 MIL-G-7421 MIL-G 81827 MIL-G-23827 MIL-G-25537 MIL-G-21164 |
-100/450 -100/250 -80/360 -100/300 -65/250 -65/250 |
Silicone Diester Diester Diester Mineral Diester |
PTFE Lithium Clay Lithium Calcium Soap Lithium |
Lavender Brownish Black Brownish Tan Black |
Shell Oil | |||||
Aeroshell #5 Aeroshell #6 Aeroshell #7 Aeroshell #14 Aeroshell #17 Aeroshell #22 Alvania #3 Cyprina #3 Dolium R #2 Darina |
MIL-G-3545C MIL-G-24139 MIL-G-23827A MIL-G-23827 MIL-G-21164 MIL-G-81322A MIL-G-81322C MIL-G-18709 MIL-G-18709 |
-20/300 -40/250 -100/300 -65/250 -100/300 -80/350 -30/275 -0/250 -30/300 -0/300 |
Petroleum Mineral Diester Mineral Diester Diester Mineral Mineral Mineral Mineral |
Microgel |
Dark Brown Amber Amber Tan Dark Gray Dark Gray Amber Lt. Tan Amber Amber |
Tenneco Chem. (Huls) | |||||
Anderol 753A Anderol 757 Anderol 761 Anderol 793A Anderol 794 Anderol 795 |
MIL-G-3278A |
-40/300 -40/300 -40/400 -65/300 -65/250 -65/300 |
Diester Diester Diester Diester Diester Diester |
Lithium Lithium Silica Lithium Lithium Lithium |
Lt. Brown Lt. Brown Lt. Brown Lt. Amber Lt. Amber Off White |
Texaco Oil Company | |||||
Premium RB Low Temp EP Regal AFB #2 Unitemp 500 |
MIL-G-23827 MIL-G-18709 MIL-G-3278A |
-30/325 -65/250 -40/250 -65/350 |
Mineral Synthetic Mineral Parafin Diester |
Lithium Lithium Lithium Sodium |
Orange Purplish Brown Green Blue |