They are still very much in use across the US. However..that being
said..so much "mass production" has gone to other countries that much
of the use that Acmes and Davenports and Coromants etc etc are pretty
much locked into companies that cant change to the expensive CNCs
stuff like Star etc etc and have products that cant be done overseas.
Id be very interested in buying some coolant pumps if you are parting
out the machines. I take care of a double handful of Acmes and Im
running low on coolant pumps.. the gears tend to take a beating if
you have ignorant small villagers from South America running them..
As you may be aware...most Acmes etc etc are now used as "roughing" or
"first op" machines as they are wearing out and finding someone to
rebuild one is both impossible and expensive as fuck.
So they are set up to do the primary machining from bar stock, then
the roughed parts go to CNC lathes for machining to specs
They very much are still used to machine things that dont need tenths
tolerances. A perfect example would be..lug nuts. Washers, fittings
and so forth. Acmes can be found that will do up to 12" diameter
parts..though they have become rather rare as has the work for them.
One of my clients
https://photos.app.goo.gl/PdgsBZPt8m3tfmdH2
These are just a few of the 12 they run. The above three run 1/2 a
shift a day..and their output is completed (finished to tolerance) on
these, over the next 2 shifts.
https://photos.app.goo.gl/EkjVFqg5mC2D1su82
Other companies...
http://www.m-reng.com/wp-content/uploads/2017/06/Equipment-4.jpg
http://www.m-reng.com/
For those who may never have seen a "screw machine"
" Multi-Spindle Screw Machines
The multi-spindle screw machine is turning machine that allows
multiple tools to cut multiple pieces of material simultaneously. Like
a Gatling gun, the multiple spindles are carried in a precision
machined drum that typically rotates in a horizontal orientation. The
total number of operations needed to complete a part are divided among
the number of spindles, so that a part is completed with one full
rotation of the drum. However, because multiple parts are being
machined simultaneously, a part is completed each time the drum
indexes, making for a very efficient process. Usually configured in 4,
5, 6 or 8 spindle models, each spindle is attacked by a cross-slide
and end-slide tool effectively making each spindle a 2-axis lathe. "
There are about 4 types..but they typically are called either "Swiss
screw machines" or "Multi-spindle" screw machines.
Mechanical Swiss screw machines are typically used for high precision
small parts under 3/4", and include Tornos, Bechler, Star, Brown and
Sharpe etc
They nearly always machine (1) part at a time, with multiple tools in
operation
https://www.youtube.com/watch?v=zymiEXw6jZU
They also come in CNC
https://www.youtube.com/watch?v=PU1-G7Eh1fk
Multi spindle machines are rather different.... They perform an
operation on each part as the part is spun around an axis. Hence you
may have 6 parts in the machine..each part is undergoing a single
machining operation, then its spun to the next tool ..then to the
next..and finally popped out of the machine into a collection area.
https://www.youtube.com/watch?v=0GFYjm5E4cA
https://www.youtube.com/watch?v=rOGdQgiBMS8
https://www.youtube.com/watch?v=HnCFDkxAVPE
They even come in CNC
https://www.youtube.com/watch?v=y2dd_G_vjGE
A rather good recruitment video....
https://www.youtube.com/watch?v=g6Pka6jrwHY&t=9s
This may give you some idea of how they are laid out....
https://www.youtube.com/watch?v=hZls0HwsIzI
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