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Date: | Sun, 19 Aug 2012 08:38:57 -0600 |
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> I have a Dadant 10/20 Stainless Steel radial extractor. The bottom
> bearings on the main shaft usually burn out every third year, right in
> the middle of extracting.
I wonder if pressure washing could be part of the problem?
http://www.honeybeeworld.com/diary/incl/DSCF4598.JPG
Pressure washers are able to easily and accidentally push water past
seals and into otherwise waterproof parts.
It is important to keep both water and honey from entering a bearing.
If water sits in a bearing for long, it will rust and pit, then become
noisy and fail after a few hours of service. Even a little honey will
cause it to heat and bind.
Bearing types designed for radial loads may have some thrust rating, and
_can_ sometimes be used for an application with thrust, but doing so is
risky design and likely to result in a short service life. Best to use
a bearing type intended for thrust in a thrust application.
The bottom extractor bearing is subjected to both trust and radial loads
(unbalance can generate significant radial loads), so the bearing
selected should be adequately rated for both types of loads. The top
bearing load is principally radial, although there is always a trust
component due to flex if it is locked to the shaft, as it should be.
Also it is easy to forget that the same bearing number from different
sources can differ significantly in noise level and also service life.
(I covered this before under a Dakota Gunness discussion, pointing out
that the original bearings were very noisy, but German replacements were
silky quiet).
Price is an indicator, but sometimes a cheaper bearing is better for an
application. A good bearing supply shop can advise.
That said, I borrowed one of these extractors one time and I seem to
recall that they are not designed for more than very light and
occasional use and that the construction is very lightweight and basic.
I also seem to recall that the bottom bearing supplied did not appear to
be a real thrust-rated bearing, but one designed for principally radial
loads.
It is possible to use a light-duty extractor in heavy service, but
problems are probable as usage hours accumulate. I used a 4-frame
reversible to extract 100 hives when I started out, but it was built
back before engineering had advanced to the point where manufacturers
felt confident enough to scrimp on material. It was heavier than a
modern 10 or 20-frame unit.
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