I will receive soon a 8x12 minilathe.

I have junk stock for practice and like to know if it is suitable for
turning.
Do not laugh please

Re-bar
Galvanized plumbing pipe, should be OK since it is threaded.
Galvanized Plumbing Fitting, cast.
Pressed powder objects.

Also, when is a collet a better tool than a chuck? What kind of situations?

Thanks

Mauro Gaetano

Ouch!


Rebar can be almost anything left over at the mill. Typically it is at
least .40% carbon, it can be much higher. Uniformity is poor. This is
nasty stuff to cut.

Galvanized pipe is not much better. The only real spec on the material
is that it hold 300 psi and be somewhat round with a hole in the center.
It usually has a tough weld seam that will bounce your tool bit
around. It also suffers from a lack of uniformity, in the same piece,
from side to side, and between pieces.

Cast plumbing fittings might be somewhat softer. Not much else to say.

Powdered metal can be most anything. The sintered bronze bearing
material cuts nicely with very sharp tools. A powdered stainless would
be miserable.

Some one else mentioned getting REAL materials:
-6061-T6 in 1/2", 1", and 1-1/2"
-some leaded steel rounds ie some 12L14 is perfect
-some brass rounds, maybe some hex

You can get any of these from www.mcmaster.com you should be able to
get some locally for half that.

Use a collet when you can for accuracy, use a chuck when you have to.




MG wrote:
I will receive soon a 8x12 minilathe.

I have junk stock for practice and like to know if it is suitable for
turning.
Do not laugh please

Re-bar
Galvanized plumbing pipe, should be OK since it is threaded.
Galvanized Plumbing Fitting, cast.
Pressed powder objects.

Also, when is a collet a better tool than a chuck? What kind of situations?

Thanks

Mauro Gaetano

MG wrote:
I will receive soon a 8x12 minilathe.

I have junk stock for practice and like to know if it is suitable for
turning.
Do not laugh please

Re-bar
Galvanized plumbing pipe, should be OK since it is threaded.
Galvanized Plumbing Fitting, cast.
Pressed powder objects.

Also, when is a collet a better tool than a chuck? What kind of situations?

Thanks

Mauro Gaetano

It would be worthwhile investing in a small stock of metals intended for
machining. Go to a place which sells metals and buy some brass and free
machining aluminium. If you want to machine steel, you can also get free
machining steel which (I think) contains a small amount of lead. Any of
these will machine much better than plumbing fittings and re-bar. Trying
to machine bits of junk will be frustrating: you'll get problems with
odd-shaped items slipping out of the chuck, poor surface finishes, and
might even damage your cutting tool or machine. I'd say a small
investment in materials is well worthwhile.

Best wishes,

Chris

"MG" wrote in message
ink.net...
I will receive soon a 8x12 minilathe.

I have junk stock for practice and like to know if it is suitable for
turning.
Do not laugh please

Re-bar
Galvanized plumbing pipe, should be OK since it is threaded.
Galvanized Plumbing Fitting, cast.
Pressed powder objects.

Also, when is a collet a better tool than a chuck? What kind of
situations?

Thanks

Mauro Gaetano


I was planning on getting an assortment of stock but the wisdom here is to
stay away from the junk pile.
Thanks, appreciate the good help.

MG

MG wrote:
I will receive soon a 8x12 minilathe.

I have junk stock for practice and like to know if it is suitable for
turning.
Do not laugh please

Re-bar
Galvanized plumbing pipe, should be OK since it is threaded.
Galvanized Plumbing Fitting, cast.
Pressed powder objects.

Also, when is a collet a better tool than a chuck? What kind of situations?

Thanks

Mauro Gaetano

Mild steel(like rebar) will generally not give satisfactory results
because it just doesn't machine well. Gummy is one word that comes to mind.

Pipe is ok but you'll need a pipe center to machine the outside and a
steady rest to machine the inside. Pipe tends to be not dimensionally
accurate and not at all round.

You later made a comment about junkyard finds. Actually there is some
very nice steel laying around in scrapyards. Look for shafting and
such. Again, mild steel will be in structural shapes and probably
should be avoided for lathe practice.
--
Gary Brady
Austin, TX
www.powdercoatoven.4t.com

MG wrote:

I will receive soon a 8x12 minilathe.

I have junk stock for practice and like to know if it is suitable for
turning.
Do not laugh please

Re-bar
Galvanized plumbing pipe, should be OK since it is threaded.
Galvanized Plumbing Fitting, cast.
Pressed powder objects.

Also, when is a collet a better tool than a chuck? What kind of situations?

Thanks

Mauro Gaetano


If you're not located where there are metal suppliers handy, don't
forget eBay.

Check out the listings under "Business & Industrial Manufacturing &
Metalworking Metals & Alloys"

Example; Here's some 3/4" diameter by 36" long 6061 aluminum bar stock
with FREE shipping:

http://tinyurl.com/o4o68

There are some pretty good bargains available that way, and I've
received some weighty quantities of short lengths of stock (bar ends)
securely taped together and mailed to me in a USPS $4.05 "Flat Rate
Priority Mail" cardboard envelopes. They let you put up to SEVENTY
POUNDS into them. Sounds almost too good to be true, but that's what
they offer:

http://tinyurl.com/ryque

HTH,

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."

MG wrote:

I have junk stock for practice and like to know if it is suitable for
turning.

Get some CRS or free machining material (with lead). It is the easiest
to work and learn with.

Do not laugh please

You will cry of you use the material you intended. :-)


Nick
--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de
DIY-DRO // Eigenbau-Digitalanzeige
http://www.yadro.de

I will receive soon a 8x12 minilathe.

I have junk stock for practice and like to know if it is suitable for
turning.
Do not laugh please

Re-bar
Galvanized plumbing pipe, should be OK since it is threaded.
Galvanized Plumbing Fitting, cast.
Pressed powder objects.
You need to get a "better" junk stock pile. G As other have said,
trying to learn on "bad" steel/metal will make your experience
miserable. If you have "good" steel/metal and can produce quality
work, then you know that you aren't doing something wrong (most
likely) when you do the same operation in the same manner using junk
steel and it turns out bad. Get a couple of chunks of 12L14 for
practice and then maybe some brass. Different techniques for each.
Good luck and ENJOY making chips.
Ken.


Also, when is a collet a better tool than a chuck? What kind of situations?

Thanks

Mauro Gaetano

MG,

Good advice is offered herein on material. As you get better with your
machining skills you can then utilize the "crappy" stuff for things
where it doesn't matter.

As to collets: These are the ultimate in precision work holding and
are used only on finished part surfaces when these surfaces are
required to be concentric with the diameter to be machined.

Do not use collets on as-drawn / rolled material surfaces since this
would destroy the collet's accuracy. Always use a chuck or face plate
for un-machined surfaces. If the material surfaces are seriously uneven
it helps to protect the chuck jaws if cardboard or soft metal is placed
between the jaws and the work. Although the chuck jaws are heat treated
and quite hard, they will wear in time. This can be slowed down by use
of protective material between the jaws and rough work surfaces.

Collets may be used on commercial ground stock such as drill rod, but
the diameter of the stock should be within +/- .002" of the collet's
size. The exception are ER collets and rubber flex collets, each of
which has a greater size range than do the more usual spring steel
collets. If the work piece diameter is slightly out-of-range of the
nearest collet size the difference may be made up with shim stock
wrapped around the work forming a sleeve.

How to tell the difference? If the collet jaws are separated by
rubber, it's a rubber-flex collet. If the collet has slots running
from each end of the collet, and each end of the collet has a closing
angle on it, it may be an ER collet or similar.

It is worthwhile for you to do a little reading on the use of collets.
It will pay off in spades as your machining ability becomes more
sophisticated!

Wolfgang

MG,

Good advice is offered herein on material. As you get better with your
machining skills you can then utilize the "crappy" stuff for things
where it doesn't matter.

As to collets: These are the ultimate in precision work holding and
are used only on finished part surfaces when these surfaces are
required to be concentric with the diameter to be machined.

Do not use collets on as-drawn / rolled material surfaces since this
would destroy the collet's accuracy. Always use a chuck or face plate
for un-machined surfaces. If the material surfaces are seriously uneven
it helps to protect the chuck jaws if cardboard or soft metal is placed
between the jaws and the work. Although the chuck jaws are heat treated
and quite hard, they will wear in time. This can be slowed down by use
of protective material between the jaws and rough work surfaces.

Collets may be used on commercial ground stock such as drill rod, but
the diameter of the stock should be within +/- .002" of the collet's
size. The exception are ER collets and rubber flex collets, each of
which has a greater size range than do the more usual spring steel
collets. If the work piece diameter is slightly out-of-range of the
nearest collet size the difference may be made up with shim stock
wrapped around the work forming a sleeve.

How to tell the difference between collets If the collet jaws are
separated by rubber, it's a rubber-flex collet. If the collet has
slots running from each end of the collet, and each end of the collet
has a closing angle on it, it may be an ER collet or similar.

It is worthwhile for you to do a little reading on the use of collets.
It will pay off in spades as your machining ability and requirements
become more sophisticated!

Wolfgang

wrote in message
oups.com...
MG,

Good advice is offered herein on material. As you get better with your
machining skills you can then utilize the "crappy" stuff for things
where it doesn't matter.

As to collets: These are the ultimate in precision work holding and
are used only snip a lot of sage and truthful pontifications that do not
apply to home shop machinists

All very true, and certainly the advice appropriate to a world-class
machinist who can't bear to work to mere thousanth's, sneers at tenth's and
is only comfortable with 1/100 thousanths, precision or better. For the
rest of us mortal home shop machinists who routinely work to within a few
thousanths and especially for newbies, some clarification is in order.

First of all, as to how close the collet should be to the stock. A typical
collet, such as 5C collet has a range of holding power. 5C collets can be
had by 1/64" increments, which allows you to work to clamp a piece that is
within +- .008". The 1/32 series collets have a wider (double) clamping
range, and the 1/16"series collets have four times the clamping range.
That is, the 1/64, 3/64, 5/64 etc. collets have a range of +-0.008
(actually a trifle better), the 1/32, 3/32, 5/32, etc. have twice that
clamping range (0.0156) and the 1/16, 3/16, etc. have double that. This
means that when you're starting your collet set you can first buy a set by
1/16", then fill in with the 1/32" range, and finally, when you're really
flush, fill out with the 1/64" range collets. Note that you need to buy
twice as many collets for each upgrade. I don't know how to buy commercial
5C collets that are with +-0.002" of an arbitrary diameter piece of work,
except by machining a machineable collet to that size or just working with
odd diameter stock.
Now granted that this is not the ultimate in accuracy, but holding
to within a thousanth is routine. You can also buy an adjust-through (also
called set-through) type of collet chuck that allows you to indicate your
work to within a 1/10th (thousanth) if you need that, and assuming that your
lathe spindle has less than that in runout, that your tool post has less
than that in slop and give, not to mention the accuracy of you bed, ways,
etc. The point is that accuracy is a cumulative process and every part of
the machine and setup must be up to the same standard or else you are just
throwing money away and fooling yourself.
Now as to the use of chucks rather than collets. A chuck is
accurate at only one diameter. And at other diameters it can be off by
several thousanths. Ideally, you would have to put a spacer into your chuck
of the right diameter, and then precision grind the jaws for that specific
diameter. Alternatively, if you're not too fussy, is to have a set-through
chuck which you can adjust for that specific diameter with the work in
place. This is time consuming and requires the use of dial indicators (or
precision test indicators for the 1/100th thou purists). An experienced
precision machinist will often choose to use a four-jaw independent chuck
which can be adjusted very precisely.
When you do need (rarely) to have a very precise fit of the collet
to the work, you can use a machineable collet. This is made of brass and is
easily bored out the exact diameter you need, as possible as it is to do on
your lathe. Always good to have a few of those machineable collets
around.. I have several, and have yet to use them.
As for "ruining" the accuracy of the collet by having it too far
away from the work diameter... yeh, certainly the case if you were in
production, making thousands of parts. For the typicaly home shop
machinists this isn't an issue because:

1) The wear and tear on the collet of one week of production work in a
commercial shop is likely to be greater by an order of magnitude than the
typical home shop machinists is likely to put on in a lifetime. This, by
the way, is one reason that when you buy used collets, you should not buy
the popular ones (1/4", 1/16" ranges) used. Such collets are often beat and
close to worthless.

2) The typical home shop machinist is not going to buy super accurate
collets such as Royals at $30 each (more for square and hex), but a good
quality generic Chinese set at $6.00 each or less on sale.

3) The accuracy super-pros I've met keep their collets in their individual
little plastic cases and would be horrified at the very thought of having
them out in the open air in collet racks. Us poor slovenly home machinists
like to have them in racks where they are handy but where their accuracy
probably deteriorates by a few millionths of an inch every week or so. If
I had a set of Royals comparable to my 5C set, I'd have them in a large,
humidity controlled, glass-fronted case, with each collet in it's own gently
cushioning felt-lined holder. And I probably wouldn't ever use them, but I
would certainly pray before that collet shrine five times a day.

Now should a home shop machinist invest in collets? Certainly a
three-jaw scroll chuck and a four-jaw independent chuck have priority. But
beyond that?

I admit that I am a collet freak. It has taken me many years,
but now I have a full set of 5C collets by 1/64", a square set by 1/16th, a
hex set by 1/16", a dozen inside collets of various sizes up to 4", pot
collets up to 6", and if they made 3 sided, 8 sided, and 7 sided collets,
I'd probably buy those too. Because my milling machines require different
collets, I also have MT-2 collet sets, 3C collets, and B&S #9 collets.
Like I said, I am an admitted collet junky.

I've got a lot of different chucks, face plates, and all that
other stuff, but I keep my 5C collet chuck on my 12" Clausing lathe and use
that for 98% of my work. The collet is more convenient, easier to use and
set-up, more accurate for routine work, holds better, gives you a less
obstructed view of your work, and is less dangerous than a chuck.

Collets are a distinct advantage in machining very thin, flat pieces
(done in a pot collet) and for machining something that must be held on the
inside. Collets are also superior to chucks when working with very small
parts. I do ship models, so I am often working with really small stuff and
only a collet will do the job. I've often thought about buying a
watchmaker's lathe for the really small work, but what's kept me from that
is the difficulty in finding one with a full collet set on the used market
at a price I can afford. Small lathes like that are often used only with
collets, it is the chuck that is the exception.

The main limitation of collets is the limitation on maximum
size. 5C collets have an upper limit of 1.125" (more with pot collets if the
work is flat and more for inside holding). The smaller 3C collet only goes
up to 1/2".
Another disadvantage for some collet set ups, is that when you
use an collet chuck on an older or smaller lathe, you can't mount the collet
directly in the lathe's spindle nose. For example, a classical South Bend
9" and my Clausing 12" have only a 3/4" spindle bore, so they can only take
3C collets or MT#3 collets. For the bigger collets (e.g., 5C) you use a
collet chuck. Well it takes a lot of turns of the chuck key to put the
collet in, tighten it, or remove it. But hey, we home shop machinists
usually have the time... especially when we spend more time looking for the
chuck key than tightening the chuck. When you have a through-the-spindle
collet set-up opening and closing is done by turning the collet drawbar
wheel which is much faster. (yeh! I know all about Sjogren chucks, but what
newbie is likely to buy a chuck that costs twice what his lathe costs?).
Boris

-------------------------------------
Boris Beizer Ph.D.
1232 Glenbrook Road
Huntingdon Valley, PA 19006

TEL: 215-572-5580
FAX: 215-886-0144
Email bsquare "at" earthlink.net

------------------------------------------

"Boris Beizer" wrote in message
ink.net...

Correction:

I don't know how to buy commercial
5C collets that are with +-0.002" of an arbitrary diameter piece of work,
except by machining a machineable collet to that size or just **not**
working with
odd diameter stock.

Of course I thought of another, very important thing you can do with collets
that is difficult, expensive, or almost impossible with chucks. I often
have to work with small-diameter, thin walled, brass tubing ... from 1/8"
diameter to 1/2" diameter. I have to cut this tubing off to make small
brass rings from 1/32" to 1/16" wide. These are used for bands on masts and
other spars. Can't do that in a typical chuck because the chuck only grabs
at three points, while the collet grabs all around. With a 1/2" tube in a
chuck, the point at which the chuck starts to hold and the point at which
the chuck crushes the tube are very close. You can use a six jaw chuck, I
suppose, but that's expensive and not as good as collets.

I'm sure that other fellow machinists out there, professional or
amateurs, will provide even more examples of where a collet is the holder of
choice, as contrasted to a chuck.

Boris

--

-------------------------------------
Boris Beizer Ph.D.
1232 Glenbrook Road
Huntingdon Valley, PA 19006

TEL: 215-572-5580
FAX: 215-886-0144
Email bsquare "at" earthlink.net

------------------------------------------

Boris Beizer wrote:
wrote in message

Gold post. Nicely done!
It belongs in the FAQ.

Regards.
Ken.
--
Volunteer your idle computer time for cancer research
http//www.grid.org/download/gold/download.htm
Return address courtesy of Spammotel http://www.spammotel.com/

"MG" wrote in message
ink.net...
I will receive soon a 8x12 minilathe.

I have junk stock for practice and like to know if it is suitable for
turning.
Do not laugh please

Re-bar
Galvanized plumbing pipe, should be OK since it is threaded.
Galvanized Plumbing Fitting, cast.
Pressed powder objects.

Also, when is a collet a better tool than a chuck? What kind of
situations?

Thanks

Mauro Gaetano



Thanks to all, valuable learning.

MG

I'm barely ahead of you but i stumbled into an amount of 3/4" buy 16
to 18" long peices of brass that were being sold for $1.80 each at lee
valley tools (Spares from their tool factory next door)

Basically to me its learner metal and easy to work

I wuould suggest picking up something similar like round bar brass as
a "student metal" especially in small amounts

HTH




On Tue, 18 Apr 2006 00:49:32 GMT, "MG" wrote:

I will receive soon a 8x12 minilathe.

I have junk stock for practice and like to know if it is suitable for
turning.
Do not laugh please

Re-bar
Galvanized plumbing pipe, should be OK since it is threaded.
Galvanized Plumbing Fitting, cast.
Pressed powder objects.

Also, when is a collet a better tool than a chuck? What kind of situations?

Thanks

Mauro Gaetano

Yeah, Ken - collet what you like. Boris's post is top drawer.

Bob Swinney
"Ken Davey" wrote in message
...
Boris Beizer wrote:
wrote in message

Gold post. Nicely done!
It belongs in the FAQ.

Regards.
Ken.
--
Volunteer your idle computer time for cancer research
http//www.grid.org/download/gold/download.htm
Return address courtesy of Spammotel http://www.spammotel.com/

According to Boris Beizer :

"Boris Beizer" wrote in message
ink.net...

[ ... ]

Of course I thought of another, very important thing you can do with collets
that is difficult, expensive, or almost impossible with chucks. I often
have to work with small-diameter, thin walled, brass tubing ... from 1/8"
diameter to 1/2" diameter. I have to cut this tubing off to make small
brass rings from 1/32" to 1/16" wide. These are used for bands on masts and
other spars. Can't do that in a typical chuck because the chuck only grabs
at three points, while the collet grabs all around. With a 1/2" tube in a
chuck, the point at which the chuck starts to hold and the point at which
the chuck crushes the tube are very close. You can use a six jaw chuck, I
suppose, but that's expensive and not as good as collets.

How about a chuck with two-piece jaws, with Pie section soft
jaws? Those could be machined to size for your tube, and would hold
contacting almost all the way around, with only fairly narrow gaps.

Or machinable soft collets could be made to fit what you don't
have a precisely sized collet to fit.

I'm sure that other fellow machinists out there, professional or
amateurs, will provide even more examples of where a collet is the holder of
choice, as contrasted to a chuck.

Well ... I consider soft jaws to be a good alternative to a
collet, as above. But one nice feature of a collet vs a regular chuck,
at least, is the ability to put a work stop to set each of a batch of
workpieces to the same depth (length). (Of course, with soft jaws, you
can turn the socket and the stop in a single setup -- with the exception
of workpieces which are longer than the depth of the jaws, but shorter
than the range of collet stops.

That said -- I use collets more often than soft jaws, because
they are convenient. :-)

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

"DoN. Nichols" wrote in message
...
According to Boris Beizer :

"Boris Beizer" wrote in message
ink.net...

How about a chuck with two-piece jaws, with Pie section soft
jaws? Those could be machined to size for your tube, and would hold
contacting almost all the way around, with only fairly narrow gaps.

I could do that, of course, but then I'd either have to have a whole bunch
of them, or a whole bunch of machinable jaws, or be constantly remachining
the jaws for the next ring size. Putting in the right size collet is sooo
much easier and faster than swapping jaws.

Or machinable soft collets could be made to fit what you don't
have a precisely sized collet to fit.

As I said, I have a bunch of those machinable collets and I've never
used them. However, last week I did get a situation in which my collets
didn't work... not the round collet, but the square collets. Too small for
the 3/16 and too large for the 1/8. Obviously I needed 5/32, but I've never
seen those around .. or I could have ground out the space between the jaws
to provide additional grap range. I just changed the stock I was using.
Yeh! Yeh! I know, I missed a royal opportunity (excuse) to spend several
hundred on a set of broaches.

Well ... I consider soft jaws to be a good alternative to a
collet, as above. But one nice feature of a collet vs a regular chuck,
at least, is the ability to put a work stop to set each of a batch of
workpieces to the same depth (length).

Good point. For the newbies, a caution. When you buy used 5C collets, make
sure that they have the ***inside*** threads for the collet stop as well as
the regular outside threads for the drawbar. Many older 5C collets do not
have the inside threads.

Boris

--

-------------------------------------
Boris Beizer Ph.D.
1232 Glenbrook Road
Huntingdon Valley, PA 19006

TEL: 215-572-5580
FAX: 215-886-0144
Email bsquare "at" earthlink.net

------------------------------------------