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Lathe and milling for platinum


#1

I am looking for anyone who has on a lathe that will work
well for platinum. I would like to find a Lathe with a milling
devise. As much for accurate layout for pave and decorative items as
I do not do mass production. This would be primarily for platinum
and higher Karat gold. I have seen (not in person) the ones in
catalogs from Gesswein, Rio, Frei and Borel etc. but they do not look
very sturdy. Are they? Or should I be searching machine shop
catalogs or talking to a machinist? If anyone has an opinion or
source please contact me. I feel with the density of platinum it
could wear our most cutters quickly and a machine might need to be
designed with that metal in mind. Is there one out there that will
work accuratly and well with these metals.

Stephen V. Lehman
S. Vincent Jewelry Design Studio
sv@svstudio.com


#2

Dear Stephen, I think the Micro Lathe sold by Frei is good, sturdy
for it’s size. You will need to order the milling attachment 141.220
separately and of course resharpen your knives but I think it would
work fine for platinum. Bill Navran


#3

Stephen, The Sherline lathe and mill are very good tools for the
money. If you want a little larger tools then the Saki lathe and
mill attachment are first class tools. Most of the other commonly
available small machine tools should be avoided.

Jim


@jbin
James Binnion Metal Arts
4701 San Leandro St #18
Oakland, CA 94601
510-533-5108


#4

I am looking for anyone who has on a lathe that will work
well for platinum. I would like to find a Lathe with a milling
devise.

I’ve been pretty happy with my Taig lathe. I’m using it to cut
stainless steel which is right up there on the huge-pain-to-work-with
metals. The Taig lathe is small, accurate, and inexpensive. I got
mine at: http://www.pioneer.net/~felice/taig.html

Tell Nick what you plan to use a lathe for and he’ll be
straightforward about whether the Taig will work for you. (Tell him
that Spider sent you. grin)

And there IS a milling attachment for the Taig.

-Spider
http://www.spiderchain.com


#5

Steven, If you are interested in the Taig lathe (which is the one I
believe Frei & Borel sell) I deal them and have a website all about
them and some other small lathes. I have lots of pictures with jobs
done on them etc. http://www.proaxis.com/~taig

As for machining platinum, I don’t think that it is harder on tools
than other metals, such as stainless steel. You may have to experiment
with tool rake angles, coolants used (for instance milk can be used
for machining copper and lead) and material such as carbide, stellite,
cobalt HSS, etc.

Let me know if you have any specific questions about what is possible
with the Taig. Nick


#6

Stephen Lehman: Any of the lathes/milling machines carried by the
dealers you mentioned will work well in platinum and any karat gold if
used properly. The determining factor is the size of the work - not
the material. Proper use entails cutting tools that are ground and
sharpened correctly, correct speeds and feeds and a whole lot of
experience. I highly recommend you buy the book "Tabletop Machining"
by Joe Martin (the president of Sherline Products). It is excellent
and will give you a great introduction to machining small parts. I
believe all the dealers you mentioned carry it. Good luck.

Ray Grossman
Ray Grossman Inc.


#7

We have been machining platinum and gold (14, 18, & 24k) for about 12
years. We use a compact 5 lathe, but the brand of lathe is not
important. If it is well adjusted and not worn out it will work fine.
Turning metal on a lathe is a large topic. In no particular order here
are some thoughts that will lead you to success. 1. Your cutting tools
must be sharp. Try new carbide bits, either C-2 or C-6. High speed
steel cutters can give a slightly better finish than carbide, but the
ease and low cost of carbide cutters make them a good choice. 2.
Adjust the gibs, they could be a source of chatter. 3. Be sure the
cutting bit is right on dead center. 4. RPM matters, there is an
optimum surface speed that the metal advances into the cutter to
produce the best results. This surface speed will vary greatly not
only with different metals but with thier hardness. 5. Cutting fluid
will ususally help and it never hurts. I have found that WD-40 is good
for every metal I have tried. 6. You can compensate for the size of
your lathe by taking smaller cuts, and by changing the rate you
advance the cutter into the metal. 7. If you have chatter try slowing
down the spindle RPM. 8. Machine tool supply companies have expanding
mandrels that are the right size for bands. These are used between
centers and are marvelous. If you are going to mill precious metals,
take lite, shallow cuts and be gentle. As a final thought, why don’t
you do your machining in file wax and cast? Think of the machining as
a step in carving wax that gives you an added degree of precision to
go with your hand work. I have found this to be useful in some types
of channel setting and inlays as well as opening up a new world of
design ideas. — John Winters <@johnjuan>


#8

Platinum’s cutting resistance is better addressed by getting carbide
or diamond tool bits. You can’t cut very long on platinum with a
steel tool before sharpening. Power and weight in machine tools is
related to depth of cut and accuracy (chatter and vibration) as it
relates to the size of the workpiece. Accuracy (not out of round) can
be greater in a small lathe but unless you are an aerospace contractor
I think you will find that almost any lathe will do. Some have a
nicer feel than others. I turn platinum bands on a $400 Taig with a
ring collet. You can make your own head divider or you can invest in
Cad Cam all depends on how much $ you can invest. John Caro


#9

I suggest anyone who wants to mill platinum look at the Platinum Day
West symposium book that will be out soon. Call Jurgen Maerz at PGI
for a date. The symposium was in September 1999, and Tino Volpe (of
Tiffany) did a good paper. One important point I remember was that
the best cutter was purpose made diamond, the phrase might have been
PCD diamonds.


#10

Steven: The Sherline, Taig, or similar lathe all work fine for
platinum. I have been milling Platinum and 18k on a 50 yr. old
Derbyshire lathe for years. If you are new to machine work, expect a
learning period…“it’s all very simple, if you know what you’re
doing!” The lathe you choose should be sufficiently stout enough not
to get bogged down when the metal grabs the cutting tool. Platinum
is “sticky” to cut. The cutting angle of your bit is also
important…it’s more like a 90 degree scraper than the angle you’d
use for brass. You don’t want the edge to “dig in,” just shave. And
it must be sharp. You’ll soon want to invest in a sharpening hone.
I found that a candle works fine as a lubricant. There are others,
but the candle works fine. You will also need a way to hold the ring
blanks. Platinum is soft, and a 3-jaw chuck will deform the ring and
leave hard-to-remove tool marks. I use a very simple inside set of
expanding collets that can be machined to hold rings of various
diameters. I need 1 for each ring size. The list goes on… The
purchase of a lathe or milling machine is only the initial
investment, the tip of the iceberg. And there is always something
else that you will soon NEED. My lathe uses 3C collets, and they’re
sometimes hard to find. My Hardinge lathe uses 4C collets, and
they’re impossible to find. I had to add an Aloris “quick-change"
toolpost, and locating metric dial indicators was a challenge. The
indexing fixture for the milling machine was pricey, but necessary
for channel work. My best advise is to make friends with a good
machinist. You’re going to ask this guy a million questions, from
"how do I” to “where do I.” You’ll soon find yourself hanging out at
used tool sales, and recognizing some of the tools. One day, you’ll
find yourself saying “If I only had a BIGGER lathe, I could make my
OWN tools!” Then you’re hooked.

Good luck.
Doug Zaruba


#11

Aloha, I would agree with Mr.Caro and the rest. Depending on your
needs is the way I would go also. The Taig is a nice little machine.
I have a Emco Maier Unimat DB200(1960’s) and SL(1970’s), they are
instrument makers combination lathe/mills/etc… Though I mostly use
one of my (2) 4 axis CNC mills (as that’s what I sell). The manual
setups are good for doing fast down and dirty procedures. I have one
set up for manual fly cutting and the other as a lathe. If you look
around you can pick up an Emco compact 5 with a milling head, which
is a nice setup. You can also go to I.Shor and get a nice quadrant
setup w/ring collets for drilling (or use an indexing head). Gesswein
used to sell the Compact 5. I have seen some on EBAY go away pretty
inexpensively. And if you wanted to go CAD/CAM/CNC, or had any
questions, you could call me. Hope this was of help.

Best Regards,
Christian Grunewald
Precision Modelmaking Technologies
Hawaii
(808) 622-9005