On 2009-07-08, Michael Koblic wrote:
Brian Lawson wrote:
Tellus 32 is a (if not THE) standard for use in hydraulic elevators as
the power transmitter. I doubt it is available retail in smaller
quantities, but is readily available in 20 litre (about 5 US gallon)
at anyplace from a Shell Distributor to a tractor supply or a good
hardware store. For a quart or two, ask any elevator company.
I have followed this thread for its educational value and potential
relevance to me in the future. I have also found a few discussions on the
topic on several different fora. I was kind of surprised that the whole
issue is akin to black magic.
Not quite that bad.
I had a look at a manual of one of the potential acquisitions (a gear-head
lathe) made in China. The instructions were to fill the gear box with "10#
or 20# machine oil". A Google search reveals no such beast. I took it to
mean SAE 10 or 20. From the various discussions it became clear that this
oil must:
1) Not have detergent
2) Not foam
3) Not have additives that attack copper/brass/bronze
If you look for a SAE 10 or SAE 20 single-weight motor oil which
is marked "ND" it *will* be non-detergent, will not have additives to
worry about, and should not foam.
The worries come with multi-grade motor oils, which *will* have
detergents, and will be made to pass through a filter (which is not
present in the oil circulation path in a lathe headstock, even assuming
that you got a gearhead lathe -- a much more serious one than the ones
with belt drive to the spindle such as mine.
A trip around town quickly established that such oil is apparently hard to
find in auto shops or tool shops. An enquiry about presence of detergent
leads to the shop staff's eyes glazing over.
Again -- look for the letters "ND" on a single-weight motor oil.
An internet search revealed
some helpful comparison charts like the one in this thread:
http://bbs.homeshopmachinist.net/showthread.php?t=27108
Further searches for *Canadian* sources of such industry standards as Mobil
Vactra suggested that this stuff is simply not available here (if you wish
further information from Mobil you can either read and accept a yard-long
disclaimer before e-mailing them or phone the 1-800 number which has a modem
on the other end!) The high end tool supplier (KBC Tools) sells EEZ way oil
but nothing specifically for gears. I did find a Shell dealer in town with
extremely helpful staff but the minimum quantities of their Tellus
(hydraulic) and Tonna (way oil) they sell were 20 litres.
Ask them who their customers are, and ask a customer whether you
can buy a couple of liters from them. Come supplied with a box of
donuts or something similar and they are more likely to be helpful. :-)
I was wondering:
1) What are the usual quantities of oil needed to fill a gear box in a
lathe?
I don't have a lathe which has a gearbox, so I don't know, but I
would suggest probably four or five litres.
2) How often do you need to change the oil?
Very seldom, once you change it once to replace the stuff the
manufacturer supplied.
3) What is wrong with just grabbing a bottle of 75W-90 or higher gear oil
off the automotive shelf? Do any of those have detergents?
If the gear assembly does not have a filter in the oil path
(unlikely in a differential or a manual transmission -- not sure in an
automatic transmission), then the oil should be non-detergent. But I
don't know how thick the oil might be. What is proper for the
differential on a car (much slower rotational speeds, and the oil is
designed for the sliding friction of the hypoid gears common in the
differential) is too thick for the higher speeds in a lathe headstock
gearbox. The oil used in the apron of my belt-drive Clausing is much
thicker and would be a very poor choice in a geared headstock.
I could find no
evidence that this is the case. Most product informations sheet contain
results of the copper strip test.
So -- you need to learn how to interpret the information
provided. (No -- I've never seen the information sheets so I don't
know.)
4) What is the downside of using a single type of oil for both ways and the
gearbox.
Waylube is *way* too thick for the headstock gearbox.
The lube for the gearbox is *way* too thin to hold its place on
the ways. And you want to frequently clean and re-lube the ways --
after each use, ideally. Among other things, this keeps water from
condensing on them.
There is some anecdotal evidence that some of the Chinese machinery that
actually comes pre-filled with oil contains inferior product that needs to
be got rid of more or less right away. Thus it would seem to me that
provided the above principles are adhered to one should get a good result
with almost anything commonly available.
Something of the right weight which is non-detergent, yes.
BTW I noticed one of the manuals recommending calcium-based grease (for
greasing, not in the gear box). Does anyone use that anymore?
Calcium-based? Not lithium based like Lubriplate (which you can
get from MSC among other places.) For that matter, you can get Vactra
and other oils in relatively small containers. However, I have gone
most of the way through a 20-gallon drum of Vacra No. 2 -- used on
several lathes, the milling machines, and the shaper.
Enjoy,
DoN.
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