Improper lubrication and contamination are responsible for 70% of all early bearing failures.
Dirt is responsible for more than 90% of all bearing troubles.
Bearing life is reduced by approximately 20% with outer race rotation.
When a bearing is press fitted onto a steel shaft or press fitted into steel or cast iron housings, the internal clearance is reduced by 80% of fit interference.
Deep groove ball bearings (Conrad) are ideally designed to permit radial loading and thrust loading from either direction (the combined load should not exceed 100% of radial load rating).
Maximum type ball bearings (with precision ground filling slots) have a radial capacity of 10% to 15% more than the Conrad type. Thrust is limited to approximately 10% of radial capacity.
The angular contact design permits this bearing to carry high thrust in ONE DIRECTION, equal to 150% of its radial load capacity.
Double row ball bearings combine the features of two single row angular contact bearings mounted in duplex.
Always check bearing fit-up after assembly.
Recommended shaft finishes for Grade 1 bearings under 2” - max. 32 rms; over 2” - max. 64 rms; housing bores - 125 rms max.
High points of eccentricity of inner and outer races of high precision bearings are marked with a burnished spot on one face.
It is desirable to press needle bearings from the lettered end.
Do not check O.D. of a drawn cup needle bearing unmounted.
Bearings lubricated with petroleum greases have a shelf life of approximately seven years.
If you double the speed of a bearing, you cut its life in half. If you double the load on a ball bearing, you cut its life to 1/8 of its original life.
Coefficient of thermal expansion for steel is .00007 inch per ºF.