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Garage Door Bearings
Our steel bearings are made of high-quality bearing steel, processed by heat treatment and precision grind, and are filled with a long service life, high-grade and multi-purposes grease.
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1" Nylon Bushing
- 2" O.D.
- For center support only.
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1" Steel Bearing
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1-1/4" Steel Bearing
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1" Football bearing
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1" Precision Flange Bearing
- 2-3/4" hole center distance.
- Includes grease zerk fittings.
- Includes locking set screws.
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1-1/4" Precision Flange Bearing- 3-17/64 hole center distance.
- Includes grease zerk fittings.
- Includes locking set screws.
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1" UCFL Precision Flange Bearing- 3-57/64" hole center distance.
- Includes grease zerk fitting.
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1-1/4" UCFL Precision Flange Bearing- 4-39/64 hole center distance.
- Includes grease zerk fittings.
- Includes locking set screws.
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Greasing Bearings - How Much is
Enough?
by Thomas
Yoon
Previously, we have talked about using suitable
greases for different applications. Basically, we want to use low temperature
greases for low temperature applications and high temperature greases for high
temperature applications. The reason is quite simple - we want the grease to
form a thin film of lubricating oil between the rubbing surfaces.
If we
use high temperature grease for normal temperature applications, the chances are
the grease will still be in semi-solid state and will not flow to cover the
contact surfaces of the moving components during operating
conditions.
Assuming you have chosen the correct grease, how do you
determine how much you need to put into the bearing?
Excessive grease
lubrication can easily cause overheating. The grease gets churned around within
the moving parts of the bearing and has nowhere to go. The temperature rises.
The grease becomes the wrong temperature selection even though the application
is correct.
A general rule to follow is that the bearing should be
filled completely but the free space in the housing only partially. This gives
room for the grease to be ejected from the bearing on start-up.
However,
there is some grease, the so-called "totally-filled" greases like lithium soap
greases that can allow filling up to 90% of the free space in the housing,
without risk of a temperature rise. This is because they are special. Their
stability at high temperatures is excellent and can be utilized over a wider
temperature range than sodium soap greases.
By filling up all the free
space, impurities are effectively prevented from entering and damaging the
bearings and the lubricating intervals can be extended.
For most other
greases, the general rule applies.
Bearings can be divided into two
categories - non-separable and separable bearings. No matter which bearing type
it is, the general practice is to fill up the space between inner race, the
outer race, and the rolling components (ball or roller) on both sides of the
bearing. Because of its consistency, the grease should be able to remain in
place without dropping off. In this way, we can ensure that the rubbing contact
surface actually has grease on it.
For relubrication, how much is enough?
The following formula gives a good indication:
G = 0.005 DB
where,
G = grease quantity in grams D = bearing outside diameter in mm B = total
bearing width in mm
By practicing proper lubrication, the bearings
should be able to last for a long time. However, bearings can still fail if it
has not been installed properly or for other reasons.
Until next
time...
About the Author
Thomas Yoon's skill in illustration/writing has
enabled him to produce numerous ebooks on engineering subjects that can be
downloaded at Engineering E-books. He has also produced an ebook on "50 Secrets of Truth and Life" that is
fully illustrated with cartoons in a humorous way.
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