"DoN. Nichols" wrote:
On 2012-02-12, Michael A. Terrell wrote:
"DoN. Nichols" wrote:
On 2012-02-11, Michael A. Terrell wrote:
I was offered an Atlas lathe the other day for $50. The owner said
that there were two damaged gears. He is supposed to give me more
information next week. Comments?
Which size? The little one (6x18") uses Zamac (pot metal)
gears, and if they are run with the mesh too tight, they start to
crumble. My example was a Craftsman rebrand of an Atlas 6x18". The
early ones were bronze bushing bearings, the later ones had Timken
roller bearings. Even with that, they aren't rigid enough for serious
work. And the beds are box not inverted V, so things aren't kept as
straight.
[ ... ]
But at $50.00, that is not a bad price. The question is --
*which* gears. If it is the back gears, it is part of the heart of the
lathe, and you will either have to hope that Clausing (who merged with
Atlas at some point) still has those parts. If it the thread cutting
gears, especially on one without a quick-change gearbox (and *all* 6x18
lathes had no quick-change gearbox), you can likely find replacement
gears -- or make them with the right tools. They are plain spur gears
with a double key, and you could make them of something other than
Zamac so they will outlast the rest. :-)
He said they were 'aluminum', and from his description, they are for
driving the feed.
Those are the Zamac (pot metal) gears, then. They sort of
*look* like cast aluminum, but they aren't. (And just as well, aluminum
gears meshing with aluminum will gall badly over time.) If you *have*
to have aluminum gears, have them mesh with steel or some other metal.
I see some gears for sale on Ebay, and some he
http://www.blueridgemachinery.com/catalog/request_a_catalog/download_pdf_catalog.html
He said that his dad was a machinist, and that he's been moving machine
tools for 30 years. He didn't use the word Rigging, so that makes me
think he just drove the truck from site to site.
These are the threading gears (whether this is the 6" or the 10"
or 12" Atlas), and having some missing will mean that there are some
threads you can't cut (until you find or make replacement gears). There
is no separate "feed" on these lathes. You have to use the half-nuts to
drive the carriage, and if you want a fine feed, you have to build up
the proper gear train, then change the gears to cut threads, then change
back to cut fine finishes again. Lathes with a separate feed take the
drive off either a separate rod or off a keyway milled in the leadscrew,
and use that to drive a gear or so in the apron of the carriage. Best
if you have both power feed (a significantly slower feed than the
half-nuts give so you don't have to change things as often), and the
cross feed (if present) is even slower. (Some Atlas 12" lathes have
quick-change gearboxes, but I *think* that they still don't have
separate feeds.
Keep some handy-wipes with an oil cutting filler because if you
keep the gears properly lubricated, you will have black hands after
changing them -- which sort of discourages changing them as often as you
should.
How hard would it be to modify it to use a stepper or servo drive?
FWIW, the back gears are Zamac too -- at least on the 6x18"
which I still have.
Still -- as I said before, at $50.00, it is not a bad price.
And it can get you experience in using a lathe, so you know what to look
at/for when it is time to get a bigger/better one.
The last lathe I used was a worn out navy surplus lathe in high
school. Both of which are long gone. I doubt that the new high school
even has a metal shop, but they spent millions on the football field.
--
You can't have a sense of humor, if you have no sense.