Greetings, folks...

Let me preface this by saying I'm a complete and utter novice when it
comes to this art -- to the point where this question is actually
asking what tool I need.

Using some standard brass 3/4" pipe, I want to resize portions of it
down to 1/2", similar to this shape:

http://devnull.dtcc.edu/gfx/shape.jpg

Can this be done with, say, a mini-lathe? I was under the impression
that a lathe was strictly for shaving down an item, but I've had
someone else suggest it can be used to actually change the diamater in
this respect.

If it is possible are there any structural disadvantages?

Thanks!
Rob

wrote:
Greetings, folks...

Let me preface this by saying I'm a complete and utter novice when it
comes to this art -- to the point where this question is actually
asking what tool I need.

Using some standard brass 3/4" pipe, I want to resize portions of it
down to 1/2", similar to this shape:

http://devnull.dtcc.edu/gfx/shape.jpg

Can this be done with, say, a mini-lathe? I was under the impression
that a lathe was strictly for shaving down an item, but I've had
someone else suggest it can be used to actually change the diamater in
this respect.

If it is possible are there any structural disadvantages?

Thanks!
Rob

It can be done on just about any lathe regardless of size. If the lathe
does not have a taper attachment then typically the compound rest is set
at the taper angle and this is used to turn the taper portion.

wrote:
Greetings, folks...

Let me preface this by saying I'm a complete and utter novice when it
comes to this art -- to the point where this question is actually
asking what tool I need.

Using some standard brass 3/4" pipe, I want to resize portions of it
down to 1/2", similar to this shape:

http://devnull.dtcc.edu/gfx/shape.jpg

Can this be done with, say, a mini-lathe? I was under the impression
that a lathe was strictly for shaving down an item, but I've had
someone else suggest it can be used to actually change the diamater in
this respect.

If it is possible are there any structural disadvantages?

This is a great example of the kind of question that is posed at too low a
level. What is it you're trying to do? Are you trying to route power to an
external building containing a swimming pool? Trying to get an old agricultural
engine running? Making a custom brass instrument?

It may be possible to swage brass pipe down this far somehow, but my guess is it
would have to be done at orange heat with special tooling on a large rigid lathe.

GWE

wrote: (clip) Using some standard brass 3/4" pipe, I
want to resize down to 1/2",(clip)
^^^^^^^^^^^^^^^^^
Whoa! If you turn down a 3/4" pipe to 1/2" OD, will you have any wall
thickness left? If you're thinking of spinning it and making the metal flow
down to 1/2", you will need better advice than I am able to give.

Making a custom brass instrument?

This actually is correct -- good guess. As I've mentioned, I'm an
absolute novice, so I'm not suprised I didn't supply enough
information; I'll try to be a bit more specific -- here is what I'm
trying to replicate or at least get something similar to:

http://devnull.dtcc.edu/gfx/brass.jpg

The body (lower part is 1/2" pipe) and the top part where it's most
wide is 3/4" -- I don't think it's a conventional brass fitting or
adapter, so I'm assuming it was either manufactured or somehow tapered
into that shape. Hopefully this is a bit more information and the
photograph will help.

Thanks for the advice and patience!

Rob

That was my primary concern -- I didn't know if a lathe could be used
to turn metal in this respect... 'bend' it to this shape rather than
cutting it down. Which goes back to my original question, can I use a
lathe to do this or am I looking for a different machine altogether?

regardless of the shape internally , you could machine this part on a lathe
, with little trouble , the internal taper is a little tricky but not really

how many do you need?

what is it worth /

have you tried getting prices from machine shops?

"williamhenry" wrote in message
...
regardless of the shape internally , you could machine this part on a
lathe
, with little trouble , the internal taper is a little tricky but not
really

how many do you need?

what is it worth /

have you tried getting prices from machine shops?


I have put a ball bearing set-up in a lathe, similiar to a single wheel
knurling tool to roll thin material into shapes. The idea of reducing the
dia. of tube may not work out to well. How about starting with the 1/2"
tube, and plug the ends, then introduce air pressure in the tube and
carefully heat it in the section you want expanded? I did this with an
expansion chamber that was smashed almost flat and the results were way
better than I expected. Low pressure and more heat is probably the safest.

Dixon

regardless of the shape internally , you could machine this part on a lathe
, with little trouble , the internal taper is a little tricky but not really

Not sure what an internal taper is, but it's good to hear that it isn't
that difficult.

what is it worth /

It really depends on the success I have -- the instrument I'm making
(an irish whistle) is broken into two parts, the body (which this is a
part of) is relatively simple -- that tapered piece with an 8" length
of tubing with specific sized holes drilled into it. That's the easy
and relatively inexensive part. The harder part, the mouth piece,
has a much more complex shape and requires me to bore out some delrin
and lathe a plug with a windway cut into it.

how many do you need?

I'd prolly try to get 25 or so to start with for my first run.

have you tried getting prices from machine shops?

No, but that's another good idea! Being primarily a progammer, I have
no clue where machine shops are around my area (Delaware), so I may
have to look around.

Thanks once again for the input and advice!

How about starting with the 1/2"
tube, and plug the ends, then introduce air pressure in the tube and
carefully heat it in the section you want expanded?

While this sounds an interesting idea, I guess I'm looking for a
technique to be able to duplicate with exact precision so I'm able to
produce instruments all look the same. Although, when I get the
equipment I need, I may try this just to see what comes of it!

According to :
regardless of the shape internally , you could machine this part on a lathe
, with little trouble , the internal taper is a little tricky but not really

Not sure what an internal taper is, but it's good to hear that it isn't
that difficult.

what is it worth /

It really depends on the success I have -- the instrument I'm making
(an irish whistle) is broken into two parts, the body (which this is a
part of) is relatively simple -- that tapered piece with an 8" length
of tubing with specific sized holes drilled into it. That's the easy
and relatively inexensive part. The harder part, the mouth piece,
has a much more complex shape and requires me to bore out some delrin
and lathe a plug with a windway cut into it.

It sounds as though you are planning to go into competition with
Copeland, who makes the nicest tin whistles that I have ever tried.

how many do you need?

I'd prolly try to get 25 or so to start with for my first run.

have you tried getting prices from machine shops?

No, but that's another good idea! Being primarily a progammer, I have
no clue where machine shops are around my area (Delaware), so I may
have to look around.

Hmm ... as a programmer, this opens the possibility of using a
CNC lathe to produce your parts. (Though it really helps to have
experience with machining before you start with CNC, just so you know
what works and what doesn't.

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 ---

It sounds as though you are planning to go into competition with
Copeland, who makes the nicest tin whistles that I have ever tried.

I'm a much bigger fan of a Burke whistle because it's sound is very
pure -- more like a piccolo and that's my preference whereas Copelands
have more of a 'chiff' sound which a lot of traditional players enjoy;
it really is a huge matter of taste. Not to mention that I'm pretty
sure Michael Copeland does this fulltime whereas it'd be more of a
hobby (unless I show a real affinity for it). So, I wouldn't say
I'd be competing against him, per se.

Just googling 'CNC Lathe' it looks they like are pretty huge, expensive
monsters -- I really am looking to start this at entry level, just to
see what comes of it. I'm definitely more of a musician than a
businessman, so the large drive of this is coming from the desire to
craft my own instruments... and it's nice to see that someone here has
actually played a Copeland! (I also play Octave Mando, and Bodhran...
picking up a 30-button anglo concertina for christmas -- saw your
website, BTW... lovely Wheatstones!)

Thanks for the suggestions -- I'm learning quite a bit (mostly what I
don't know ;p) and appreciate how helpfull you folks are here.

Rob

regardless of the shape internally , you could machine this part on a
lathe
, with little trouble , the internal taper is a little tricky but not
really

Not sure what an internal taper is, but it's good to hear that it isn't
that difficult.

what is it worth /

It really depends on the success I have -- the instrument I'm making
(an irish whistle) is broken into two parts, the body (which this is a
part of) is relatively simple -- that tapered piece with an 8" length
of tubing with specific sized holes drilled into it. That's the easy
and relatively inexensive part. The harder part, the mouth piece,
has a much more complex shape and requires me to bore out some delrin
and lathe a plug with a windway cut into it.

how many do you need?

I'd prolly try to get 25 or so to start with for my first run.

have you tried getting prices from machine shops?

No, but that's another good idea! Being primarily a progammer, I have
no clue where machine shops are around my area (Delaware), so I may
have to look around.

Thanks once again for the input and advice!


E-mail be an accurate print and I'll give you a quote for them.

Oh...and a way to a hold of you...phone number, by preference.

E-mail to mdavenport(at)iname(dot)com

replace the obvious stuff as needed.

Mike

wrote in message
oups.com...
Making a custom brass instrument?

This actually is correct -- good guess. As I've mentioned, I'm an
absolute novice, so I'm not suprised I didn't supply enough
information; I'll try to be a bit more specific -- here is what I'm
trying to replicate or at least get something similar to:

http://devnull.dtcc.edu/gfx/brass.jpg

The body (lower part is 1/2" pipe) and the top part where it's most
wide is 3/4" -- I don't think it's a conventional brass fitting or
adapter, so I'm assuming it was either manufactured or somehow tapered
into that shape. Hopefully this is a bit more information and the
photograph will help.

Thanks for the advice and patience!

Rob

Machining that part would entail starting with stock thick enough to form
the larger OD (outside dia), then removing metal both externally and
internally to form the tapers and possibly the bore diameter. If the inside
can be a straight bore rather than internally tapered, this is probably
easiest -- though the resulting part might be a bit heavy and I've no idea
how it would perform musically.

If I were making 25 or more of these, I would make an expanding mandrel so
they could be made from 1/2" tube. In your case, have a machineshop make
the mandrel. The mandrel would have several segments and possibly an
extractable central cylinder so it could be removed once the shape is
formed. I would anneal the tube, insert the mandrel, chuck the lot up
in about any lathe, and apply a roller to the metal while expanding the
mandrel. The action of the roller pressing the tube wall against the
mandrel (with some force) will gradually stretch the metal to shape.
Then collapse the mandrel, pull out the center and then the segments from
the finished workpiece, and so on.

I think the workpieces would only take a very few minutes to make, once you
had the mandrel.

On 13 Nov 2005 04:48:35 -0800, wrote:

G'day Rob

I wear very large " L " plates for metalworking so my ideas may not
be practical.

Using some standard brass 3/4" pipe, I want to resize portions of it
down to 1/2", similar to this shape:

http://devnull.dtcc.edu/gfx/shape.jpg

The internal swelling is the hard part and I think it would have
to be made in two parts and joined.

If I were making it, I would turn a mandrel of the internal shape
and then roll sheet brass around the mandrel in two parts, soldering /
brazing each half at the join, removing from mandrel and then joining
both halves together. If you have no lathe, I am sure one of the
members would be able to make a mandrel for you. I have insufficient
skill at lathe operating as I find it hard to get a smooth surface to
my work and postage from Oz would be expensive.

The brass sheet would need to be annealed to make it easier to work.

Other members of this newsgroup are far more experienced than I am and
will, I am sure, have better suggestions, or improvements to my idea.

HTH



Alan
in beautiful Golden Bay, Western Oz, South 32.25.42, East 115.45.44 GMT+8
VK6 YAB ICQ 6581610 to reply, change oz to au in address

In article . com,
wrote:

How about starting with the 1/2"
tube, and plug the ends, then introduce air pressure in the tube and
carefully heat it in the section you want expanded?

While this sounds an interesting idea, I guess I'm looking for a
technique to be able to duplicate with exact precision so I'm able to
produce instruments all look the same. Although, when I get the
equipment I need, I may try this just to see what comes of it!

There is a variation I have read about being used industrially:

Make a two-piece external mold (of metal) that completely surrounds a
piece of 1/2 inch brass tubing, with the annealed part of the tube lined
up with the expanded part of the mold, and force oil into the tube,
hydraulically expanding the tube into the mold.

The key is making the mold assembly strong enough that the hydraulic
pressure won't blow the end plugs out, or spread the mold halves. If
the mold is a split cylinder with two screw-on end caps, it should work.

The end caps would also have a fitting at each end that slides into the
tube, and is sealed with O-rings to the inside of the tube. One fitting
is blank, and the other has a port to admit the oil. These fittings are
loose, and do not turn as the end caps are tightened, but are held
against blowout by the end caps. The external mold restrains the tubing
so it cannot expand enough to bypass the O-rings. Trim tube on lathe
before expansion, to ensure a good fit in the mold assembly.

The slight relaxation of the brass after the pressure is removed should
allow the expanded tube to drop out of the half-molds. If not, split
the mold into three pieces (which will resemble pickles). Or, stick a
steel rod through the tube and nudge it with a hammer.

Joe Gwinn

"Joseph Gwinn" wrote in message
...
In article . com,
wrote:

How about starting with the 1/2"
tube, and plug the ends, then introduce air pressure in the tube and
carefully heat it in the section you want expanded?

While this sounds an interesting idea, I guess I'm looking for a
technique to be able to duplicate with exact precision so I'm able to
produce instruments all look the same. Although, when I get the
equipment I need, I may try this just to see what comes of it!

There is a variation I have read about being used industrially:

Make a two-piece external mold (of metal) that completely surrounds a
piece of 1/2 inch brass tubing, with the annealed part of the tube lined
up with the expanded part of the mold, and force oil into the tube,
hydraulically expanding the tube into the mold.

The key is making the mold assembly strong enough that the hydraulic
pressure won't blow the end plugs out, or spread the mold halves. If
the mold is a split cylinder with two screw-on end caps, it should work.

The end caps would also have a fitting at each end that slides into the
tube, and is sealed with O-rings to the inside of the tube. One fitting
is blank, and the other has a port to admit the oil. These fittings are
loose, and do not turn as the end caps are tightened, but are held
against blowout by the end caps. The external mold restrains the tubing
so it cannot expand enough to bypass the O-rings. Trim tube on lathe
before expansion, to ensure a good fit in the mold assembly.

The slight relaxation of the brass after the pressure is removed should
allow the expanded tube to drop out of the half-molds. If not, split
the mold into three pieces (which will resemble pickles). Or, stick a
steel rod through the tube and nudge it with a hammer.

Joe Gwinn

hydroforming. they make the main chassis rails of corvettes and caddy xlr
cars that way.

Go to a shop that makes hydraulic hoses and ask about their swaging
dies. (Some people say "swedge"). Those things reduce tubing to a
smaller diameter to clamp the hose to the end fitting. Especially look
at how complicated and expensive they have to be to do the job on
material a lot thinner than brass pipe.

OTOH, annealed copper water pipe is pretty easy to expand or compress
in a lathe.

jw

You know, guys...

Looking further at the design, I'm kind of boggled now... The ends of
the piece are 5/8", but on the top end, just at the top of the
expansion, there's something like a sheath that runs the length of the
pipe to the end to allow a 1/2" pipe to fit in snugly (with a tiny bit
of machining). So now, I'm starting to wonder if it was a brass pipe
1/2" in diameter, with 1/4" wall thickeness to turn both the inside and
outside.

Heh, I might have to rethink this design a bit.

tomcas wrote:

wrote:


Using some standard brass 3/4" pipe, I want to resize portions of it
down to 1/2", similar to this shape:

http://devnull.dtcc.edu/gfx/shape.jpg

Thanks!
Rob

It can be done on just about any lathe regardless of size. If the lathe
does not have a taper attachment then typically the compound rest is set
at the taper angle and this is used to turn the taper portion.

All the 3/4" pipe I've seen, if turned down to 1/2" will leave nothing
but air in the half inch area. :-)
Sort of like the 1" hole in a 1/2" peice.
...lew...

With the right setup you can do some metalspinning to alter the shape.
Unless very crefully thought out you wind up with some very thin areas.
The metal needs to be annealed to soften it and spinning will harden
it.

I believe, but have no referances, that brass instruments are formed
from sheet stock and the seams brazed and polished.

wrote:

With the right setup you can do some metalspinning to alter the shape.
Unless very crefully thought out you wind up with some very thin areas.
The metal needs to be annealed to soften it and spinning will harden
it.

So you anneal it again. This method can work, if the form is something
you can melt out again.

I believe, but have no referances, that brass instruments are formed
from sheet stock and the seams brazed and polished.

Yes, also some parts are drawn from seamless tubing. Techniques tend
to be a combination of hammering, burnishing, spinning, and drawing,
often with different makers choosing differently even for the same
part. For example the bell section can be formed as a cone (possibly
with an insert to complete it) and hammered to expand the flare and
spun to shrink the neck, or you can spin a flat disk into the bell and
join it to a seperate cone... Tapered tubes can be formed from
trapezoidal sheets and drawn to size, or simply drawn down from tubing
over a mandrel, using an annealed fender washer as a die.

Don Foreman wrote:

Machining that part would entail starting with stock thick enough to form
the larger OD (outside dia), then removing metal both externally and
internally to form the tapers and possibly the bore diameter.

The instrument industry does produce some parts by machining down and
boring out barstock. Typically they like not to do precise cutting
operations more than once, so it would be done with step drilling and a
custom reamer, but CNC equipment both within the industry and at job
shops is changing that.

One difference when machined from bar stock is that the material is
likely then a leaded brass, C360 say, instead of the unleaded brass
more common in tube stock C260, though some is a leaded C330. This has
possible implications if the part is a mouthpiece and will not be
plated.

With that last comment I think this link was posted here some time back
regarding brass instrument manufacture

http://www.zacharymusic.com/Zachary_...900Factory.htm

wrote:

With the right setup you can do some metalspinning to alter the shape.
Unless very crefully thought out you wind up with some very thin areas.
The metal needs to be annealed to soften it and spinning will harden
it.

I believe, but have no referances, that brass instruments are formed
from sheet stock and the seams brazed and polished.