'Been looking for a small lathe I can quickly upgrade to CNC.
Among them is the Shop Fox 13x40 M1098. A hands-on look makes it seem like
a pretty well-made machine for an off-shore rig.
Anybody here have any experience with them?
LLoyd
Have you looked at buying a dead CNC lathe? It does take searching but
you'll be way closer to your goal. I'm partial to Hardinge because so
dang many were made twenty years ago.
That said, looks like a decent enough import lathe. I'd have a design
concept in mind for your ball screws and stepper/servos before you
buy.
Karl
Karl Townsend fired this volley in
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I have looked, Karl, but two things stop me. Most of the used CNC machines
I'd have access to (say, in a 200 mile circle of me) are darned-well USED,
and not in stellar condition.
Also, I cannot do the tax re-capture single-year amortization of a used
machine. Buying new gets me an ROI of about 16 months.
The guys at Mach Motion have already done a nice conversion of exactly the
same model lathe of a different badge. I'm not overly impressed with the
Mach3 control, which apparently has trouble doing threading unless you buy
the (additional) MachMotion $2550 stand-alone motion controller that goes
between Mach3 and the drivers.
I'm pretty certain that Iggy has proven EMC will do it without all that
additional computing power and unsupportable embedded proprietary code.
However, since they've converted a lathe that is mechanically identical to
the Shop Fox, I assume it's not to ugly mechanically -- and heck! I'll
have the lathe working in manual mode to do the work .
LLoyd
How about starting with a Lancer lathe? i see a fella here offering a
project lathe cheap. And you wouldn't have to take it apart first
I bet he'd find you some ball screws and servo motors to sweeten
the deal.
Seriously, that would make one hell of a lathe.
Karl
Lloyd, my opinion is worth $0.01, but I feel that I have to state it.
CNC retrofit of a machine that is built as a CNC machine, is a
COMPLETELY different type of project than a CNC retrofit of a manual
machine.
If the difficulty of the former is 6 on the scale of 1-10, then the
latter is 9-10.
You have to be essentially a CNC machine designer, make a lot of
things fit that do not want to fit, make and mount a lot of brackets,
doodads, switches. Also you need to buy servo motors.
It all seems simple conceptually, until a) you start doing it and b)
make some mistakes that you realize late in the game. For sure it is
NOT cheap, if you price your time at $5 per hour and up.
I agree that a CNC lathe that is not totally clapped out, is harder
to find that a mill or a VMC.
I may be overstating my case or just not experienced enough to breeze
through that sort of thing. But somehow, I feel that retrofitting
manuals machines is not nearly as cost effective as taking a CNC
machine with a bad control.
i
I've followed the Mach3 forums for years and I've not heard of anyone
reporting problems with threading. Sounds more like a sales pitch to
sell the extra hardware.
Mach3 is based on EMC. Mach3 is also well supported.
Always good to be able to follow an existing design vs. rolling your own
design.
Ignoramus18335 fired this volley in
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Ig, I take your advice seriously, but I have the advantage that they have
already converted one of these. Only two small issues must be resolved
on my end:
I must make a ball nut bracket for each of the Z and Y feeds, and I must
add thrust bearings to the ends of the screw brackets to take out end
play. They have motor mounts and couplers designed to purpose, and the
adaptor plates and couplers only add about $50 to the total bill --
saving me much layout and machining time.
I have pretty much exhausted the near-regional used CNC lathe market
looking for anything that doesn't have so much wear as to require a full
screw and motor upgrade (and way scraping), and I think I'd rather do the
conversion. I intend not to kill the manual functions until everything
is ready (although I'll probably do several disassemblies and re-
assemblies of everything before I'm done).
Things like mounting limit switches are just not that much of a
challenge.
As for mistakes? Yeah... but they're all "recoverable", so long as I
don't invest in motors or ball screw assemblies that are sub-standard.
To that end, I'll be using some proven motors, and precision-ground
screw/nut combinations. The precision of rolled screws just leaves me
cold -- 0.003" per foot is crazy sloppy.
LLoyd
Gunner Asch fired this volley in
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I need a pretty good-sized work envelope. That's one reason I'm going with
a 13x40 manual.
What models do you have, how much, what condition of mechanics, and how
much for shipping one to Florida?
LLoyd
Ignoramus18335 fired this volley
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In any case, this will be pretty rapid-fire, except, perhaps, for the
budget. The motors and drivers will cost me $1200 for new, proven AC-
Brushless Servos and 2500 line encoders. That's the biggest rub. The
screws are pricey anywhere you get them, when you go to the 0.0005"/ft.
versions.
I'll be working hard to preserve all of the manual features except for
threading (I have a 6x18 that can do for the time being), until that very
last moment when I "switch over".
LLoyd
I've only seen two used lathes in my area in two years, and you
wouldn't have wanted either of them. At least one was scrapped because
it needed so much work.
Gunner Asch fired this volley in
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And that, plus heavy-duty shipping. That's why I'm keeping my look to a
200 mile radius.
I sold my F.E. Reed and Cincinnatti #2 to a guy three hours away, and he
took them grinning. But, then, the only diseases they had were pure age
-- ways scraped, bearings running close and smooth.
LLoyd
Old Okuma cnc lathes are very good candidates for retrofitting. Find
one with an old OSP 2000 control and you will have a very good start.
The biggest problem is that they used absolute encoders which were great
on the original lathe setup. No homing was necessary.
John
The option is to use glass scales with a rolled screw. AS long as the
ball screw has no backlash the glass scale will give accurate position
with no backlash.
John
Don't forget that CNC controls include screw mapping / pitch error
compensation. Measure and map the screw once and all the inaccuracy is
gone for good, or at least until you wear out the screw. Commercial
machines / controls use screw mapping as well.
"Pete C." fired this volley in news:4dd28edf$0
$10550$ snipped-for-privacy@unlimited.usenetmonster.com:
Yes, true enough, but the one thing I don't have is the gear to measure
that over 30-some inches of carriage travel. On the one hand, the
hardware would be cheaper, on the gripping hand (using precision screws),
I wouldn't need the instruments (I can live with a thou. over three
feet). Maybe I could get someone who does have the tools to come do the
mapping...
LLoyd
There are calibration service companies that will do the job with laser
interferometers. There are home-made solutions, but they're very tedious and
slow. And I forget what they are. d8-)
"Pete C." fired this volley in news:4dd2914a$0$10550
$ snipped-for-privacy@unlimited.usenetmonster.com:
Not hardly, Pete. I've watched that procedure before on big VMCs. You
want not only "localized" errors, but cumulative errors to be mapped.
As Ed stated below, the Japanese techs were using laser devices. The could
map a 6' travel to half a tenth, cumulative, easily. (I'm betting it was
better than that)
LLoyd
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