In article ,
Allan Adler wrote:
I've been trying to follow up on details of some suggestions.
[ ... ]
Hence, regarding CNC: it was mentioned that Nick Carter has some device called
a Frog for upgrading a Taig lathe to CNC for about $200. I'm not sure what
assumptions are made regarding the configuration about the Taig nor what
assumptions are made regarding the computer to which the Frog is supposed
to be able to be connected, if one wants to connect the Frog to a computer.
To take an extreme example, suppose I find a vacuum cleaner discarded on
the street and perform a motorectomy on it and order the K1019 deal at
http://www.taigtools.com for $144.50 and one Taig Frog for $199 from Nick
Carter. Then for a total of $344, more or less, I have a lathe and a Frog,
but it's not clear to me whether there is enough Taig there to use the
Frog with it. Obviously, one can't have the Frog tell the Taig to do stuff
that requires a tailstock, but there are things one can do without a tailstock.
(More on this below.) As regards the computer, will the Frog work with the
computer if it is a PC running some version of RedHat Linux (as mine is)?
O.K. The "frog" is not a part of Taig, or of Nick Carter. It
was started by another person, who during the last year dropped the line
and it was picked up by yet another. (I should remember the name of the
latter -- from a mailing list in which I participate -- but I don't.)
Have a look at this URL (which mentions Nick Carter, as he is
the premier worker with the Taig.
http://www.avatartools.com/
and this subpage shows one fitted to a Taig:
http://www.avatartools.com/Merchant2...gory_Code=Taig
Note that you do not *need* a computer at all. The frog
contains a keypad to allow you to enter commands to it. (A computer is
probably easier to save programs and re-load them -- especially if it
takes a lot of keystrokes to enter the program.
I don't know whether there is anything locking it into Windows,
and I somehow doubt it. Just a simple text transfer should be
sufficient.
[ ... ]
The part list of the
Taig Micro Lathe II kit mentions a bed but doesn't mention anything about
ways. I think I'm supposed to realize that the bed includes the ways.
Yes. The ways are a steel dovetail, which is mounted onto a
aluminum bed filled with concrete to minimize vibration and chatter.
In the Gingery lathe, there is a lead screw. I'm not sure but I think the
analogous part for the Taig is 100-09, which is the carriage rack (there is
also a pinion gear, so I think I am still within bounds of the subject
"rack and pinion").
Larger lathes have a rack-and-pinion to move the carriage under
control of the handwheel, and the leadscrew is only used with the
gearbox for threading and power feed (and on the better ones, power feed
picks up rotation of the leadscrew through a keyway milled along its
length, to drive a gear train connected either to the handwheel (for
slow longitudinal feed), or the cross-feed crank (for facing). This
reduces wear on the threads and half-nuts over the life of the lathe.
Smaller machines may have a leadscrew which is only operated by
a handwheel at the end of the bed, so it is very slow to go from one end
to the other. The Unimat SL-1000 (and DB-200) were of this type. The
Taig has only the rack and pinion, and the frog kit for the Taig is
designed to work with this. According to the web page, if you want to
use it with a Taig which has been retrofitted with a leadscrew, you want
to order the Sherline kit, which suggests that the Sherline is similar
to the earlier Unimat machines.
On p.100, Gingery writes: "At this point, you have
built a lathe that is as complete as some that are sold commercially.
If you have been in the market for a lathe very long, you are not surprised
to learn that some lathes are sold without a tail stock. I could hardly call
a tail stock an accessory, as some do, but the partially finished lathe can
do many jobs now." Gingery declines to say what the jobs are that the
partially finished lathe can do, but How to Run a Lathe says: "Work that
cannot readily be mounted between the lathe centers is usually held in a
chuck, as shown above, for machining." I assume that is meant to include
the case where there is no tailstock. It goes on to mention, specifically:
(1) taper turning with a chuck and compound rest
Limited to the length of travel of the compound.
and (2) cutting screw
threads with a chuck and compopund rest, using gears that connect the
headstock spindle to the lead screw."
Except that there is no leadscrew on the standard Taig. But,
there are other ways to cut threads -- with the Frog driving the
carriage.
Maybe there are other things and
maybe more can be done using the Frog with it, but I don't see it clearly.
For example, I'm not sure what, in the case of the Taig, would take the
place of the gears that engage the screw thread to achieve (2).
The Frog monitors a sensor on the headstock of the lathe, which
produces a pulse once per revolution. It times the delay between pulses
to calculate the RPM, and then drives the carriage at an appropriate
speed to cut the thread, It always starts just after one of the pulses,
so the successive (deeper) cuts are made along the same track.
It is possible to fit a lathe with two Frogs, interconnected,
so you can turn tapers using that.
Note that when turning with a chuck, and no tailstock, you are
limited in the length of the workpiece extending beyond the jaws of the
chuck. This must be limited to something like no more than perhaps
three times the diameter, or the flex of the workpiece material will
introduce errors. A tailstock, with a live (or dead) center can allow
much longer cuts, as the workpiece is supported at both ends, and the
bending moment of the middle makes it able to work beyond twice the
maximum length when using just the chuck.
There is also available a stead rest, which can support a
workpiece some distance beyond the chuck, without needing a tailstock.
Regarding the motorectomy, I'm reading the book, "Fractional horsepower
motors: use, selection, operation, repair and maintenance", by Rex Miller
and Mark Richard Miller. I'm about 100 pages into the book and a lot of
just goes past me, but it has already discussed removing and repairing
a vacuum cleaner motor. The book lists a lot of tools and parts one needs
to get involved with motors, probably adding up to a significant investment,
but I think the authors are assuming that anyone who reads the book is
probably giving at least some thought to opening up a repair shop. What
one actually needs just to scavenge one motor from a discarded vacuum
cleaner for use with a lathe is probably not much.
A Vacuum cleaner motor may not be a satisfactory one -- in part
because it tends to be more of an open frame format than most others,
and thus allows chips from the lathe to get into the motor, and
possibly damage it. In the vacuum cleaner, it is protected by the bag
or filter in the cleaner.
Incidentally, the micro lathe parts diagram and parts list at the Taig
site seems to have a small typographical error: there is a part in the
parts diagram labeled 100-28 but there is no such part in the parts list.
I have not looked at that, so I don't know.
I seem to remember you mentioning the lack of a dog and a
faceplate (somewhere in the trimmed text, I suspect). Note that as long
as you can mount a center in the spindle and access it through the
chuck, you can use a jaw of the chuck to drive a lathe dog. (And, you
can *make* a lathe dog, if you can't find one of the needed size --
especially in these smaller sizes.)
But -- there is a faceplate available for the Taig. One with
T-slots, so you can bolt a workpiece to it which can't be held in the
chuck, among other things.
And a (small) faceplate is not that difficult to make, if you
also have milling capability.
Enjoy,
DoN.
P.S. I suspect that you would get more immediate positive feedback if
you bought the Taig with as many accessories as you can. Making
your own is best done for a later machine, if needed, when you
have the skills needed.
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