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Heavy wall tubing


#1

I need some help here. I need some small very heavy wall seamless
tubing. I’ve been unsuccessful in finding what I need from any of the
usual suppliers. I’ve looked through my library and don’t find
there either. I’ve searched the orchid archives and
googled the question several ways so I turn to this remarkable
community for help. If there is a good description anywhere in a book
or online, please clue me in.

What I need is tubing with a 0.8 mm or 0.9 mm wall and an inner
diameter of 0.8 mm up to 1.1 mm. It needs to be seamless because I am
using it for making hinges.

I would appreciate details on how to draw down larger tubing to this
approximate size. I’d also like to know the relationship between
starting and ending sizes. Does the wall get thicker when you draw
it down? Do you need to do something to keep the hole from closing
up? I do understand that considerable strength or a draw bench is
needed. Do you have recommendations for the type of material for the
drawplate necessary. I’ve seen some that use exceptionally hard wood

  • would that work?

I’ve read about some means to create a tapered plug that is soldered
into the starting tubing that is unclear to me. I would welcome
recommendations on sources for either this item, or a source for
tubing to start with. Indian jewelry supply has something that would
seem to be a starting size, but their website is down right now.

Has anyone seen something this small done with deep draw technique?

Thanks in advance -
Judy Hoch


#2

Hi Judy,

If you take normal seamless tube, and draw it down, the wall will
get thicker as it comes down. There is a mathematical relationship
in there somewhere, but I’ve never known what it was. Jim Binnion
probably does, if he’s reading this.

I remember reading (somewhere) about drawing tube to a specific ID
using steel rod. The idea was to get steel rod of the same OD as the
tube ID you’re after. Taper the leading end of the tube so you can
get it through the drawplate. Heat steel rod to get a solid oxide
coat on it, then clean the very leading edge so that you can solder
the steel rod to the leading end of the tube. Draw the tube as per
normal, (with a bench) and the silver will pull down and get
thicker, until it locks up solid over the steel rod. Figure the
final drawplate hole such that you get to the proper OD as soon as
possible after the silver goes tight against the rod, because you’re
forging the silver against the rod once it runs out of airspace to
collapse into. According to whatever I was reading, you leave the
steel rod a bit long, and once it’s all pulled to size, you cut off
the leading end of the tube (and the soldered bit of steel). You
then reverse the tube and find a drawplate hole where the steel wire
just sticks through. Feed the wire through the drawplate backwards,
so that the end of the silver tube butts up against the flat plate
face around the hole, and try to pull the steel rod out with the
drawbench. If the oxide layer on the rod is thick enough, allegedly
it’ll all pull out OK. I’ve also heard about this whole trick, but
then using acid (probably fresh pickle) to dissolve the iron rod
out.

I make no warranty about that working. I remember reading it once
upon a time, but I’ve never done it, and I can’t even remember where
I read it. It’s a start though.

As far as dies and power, no way hardwood will come close to what
you need. For this, it’s steel at least, and you’ll need a
drawbench. (But I thought you already had one?) If you don’t have
one, I’m sure you two have the gear stashed away in that garage to
fake one. They’re not hard.

Regards,
Brian


#3

Judy- Tim and I make our own seamless platinum tubing and we also
draw down pre made gold and silver tubing as needed.

You will need to beg, borrow, or steal a draw bench.

I solder a wire into the open end of the tube and anneal the rest of
the tube as well. We then use a draw bench to draw the larger and
heavier stuff down.

If you can’t get your hands on a draw bench you may need to custom
order it from your refiner.

Have fun and make lots of jewelry.
Jo Haemer
www.timothywgreen.com


#4
I've read about some means to create a tapered plug that is
soldered into the starting tubing that is unclear to me. 

Drawing seamless tubing from tapered plug is an industrial
technique, which is very difficult to implement in small shop. You
mentioned dimensions requirements of 1mm wall and 1mm inner diameter
( I simplify for ease of demonstration ). No mention of the length
were given, so I assume 30mm. Not every part will be usable due to
soldering of drawing rod and end thinning, so we have to compute for
50mm length.

First compute the volume of final product. Volume of any tubing is
volume of cylinder with outside diameter minus volume of cylinder
with inside diameter. (3.141.5^250) - (3.140.5^250) = 354.4 -
39.3 = 315.1mm^3 We have to start with disk having the same volume.
Thickness of the disk is a matter of judgement based on graduation of
drawing plates. Let’s assume 2mm. The diameter of such disk must be
sqrt(315.1 / 2 / 3.14) * 2 = approximately 15mm. If you have tools
and equipment to work with such disk, than proceed as I showed in
video Goldsmith Chronicles, The Bubbly Tale.

http://www.ganoksin.com/gnkurl/1b6

Once you achieve tapered cone, you solder rod to smaller end, and
proceed to draw it trough draw plate with largest hole corresponding
to large end of the cone. Rod is used for tangs to grab on in the
beginning stage. When inner diameter becomes 1mm, - cut off soldered
end to expose hole and force lubricated steel core inside. Continue
to draw until outside diameter is of the right size. After core is
withdrawn, the tubing is ready for use.

An interesting point to observe is what happens if instead of 2mm we
start as close to desired thickness as possible, let’s say 1.1mm
Putting aside extra care required, the disk diameter becomes 21mm.
The large end of starting cone will be around 8mm. So if drawplates
with large diameters are available, working with thinner disk
requires less effort, but more care.

Leonid Surpin
www.studioarete.com


#5

Judy

Handy and Harman make thick wall tubing that should be close enough
for your needs. 1 mm wall seems overkill for hinges but H&H may draw
custom for you. You can draw thick wall tubing but again that scale
would be very tough pulling. Do you have access to a draw bench? You
might consider casting some wax tubes to make your hinge parts if you
only need a small number. Most of the goldsmithing books have making
tube, thickness, drawing, instructions in them. Good luck with your
projects.

Sam Brown
San Jose


#6

It is possible to make hinge knuckles out of sterling silver
Precious Metal Clay. You could make knuckles that are exactly to
your specifications. Just one option.

You can also make your own tubing to your specs, too. Easier to do
in metal clay and the sterling silver clay is certainly durable
enough for this purpose.

Linda Kaye-Moses


#7
If you take normal seamless tube, and draw it down, the wall will
get thicker as it comes down. There is a mathematical relationship
in there somewhere, but I've never known what it was. Jim Binnion
probably does, if he's reading this. 

Unfortunately it doesn’t really get much thicker, just longer :frowning:
While there is a tiny increase in thickness as you draw it down you
really need to start with the wall thickness you want.

James Binnion
James Binnion Metal Arts


#8

Judy, first I seem to have seen smallish heavy walled tubing in
Hoover and strong’s catalogue…barring a custom order.

you can draw tubing, despite what anyone says, with well annealed
metal (. 999 silver or high karat golds work best) using a drawplate
*OR * a sturdy ( metal ) screw gauge - you don’t need a drawbench
for small lengths of tubing however it will have a seam that you can
easily close and clean up using successively finer grits of films,
discs, papers, etc. then finishing to the polish or texture of your
choice…but it is the easiest way to get a heavy wall and the exact
specs you need in a few hours. I have used this method many times
and it works well: starting with a tab on the length of metal you
wish to form to hold it fast in a pair of draw tongs or, if you don’t
have any tongs even pliers without smooth jaws will do. And as you
draw the metal ( annealing as needed as it work hardens) it will thin
somewhat, and the tool you use for your drawplate adds to the
differential as well: sapphire lined drawplates create the least
thinning, a basic screw gauge -the least thinning as it allows the
largest holes with which to form tubing.

I’m guessing you don’t want to make hinges with rolled tabs around a
wire or tube that you could then set with stones ( if it works with
your design) - but having a better idea of the hinge’s application
would be nice: if the hinge is very small, as though to make a pair
of earrings sway compared to that of a box lid or large pendant, or
consecutive bracelet elements there are many possibilities for the
best and longest wearing option should you 1) not be able to find a
ready made seamless mill product, or 2) you don’t want to make your
own that would require finishing to appear seamless…

Starting with larger tubing won’t work unless you have a drawplate
with the exact size o. d. end product you need and a length of piano
wire or other hardened metal wire that fits perfectly to maintain
the inner diameter you want to result in, which would require a
length of extra heavy walled tubing that can be drawn down that is at
least. 02-. 4mm larger than what you need the result to be- a hard to
do task at best…If by some miracle you have an extra heavy O. D.
walled tube, and a few successively smaller very hard insert wires
you could, in theory get what you want with a lot of stick type
lubricant - brass won’t work, and the smallest cold rolled steel
readily available is probably too large for your requirements.

An option in your area ( whatever that is) may be a machine shop
willing to manufacture a small lot of tubing for you provided their
equipment can be set up for " jeweler’s size" tubing. It would be
seamless but you may wind up paying more for their potential set up
cost, than just changing your specs a bit to buy mill products from
your regular vendors…

If you decide you want to try the short cut method using a 2 dollar
metal screw gauge contact me off list and I will give you all the
instructions ( really quite easy to achieve in a couple or three
hours time using fine silver or 18-22 karat gold - but they are soft
and the insert wire for the hinge should be 14 kt or even 12, 10 kt.
if gold or sterling if using silver to give the hinge it’s longest
wearing capacity. Also if you are using tubing solely to make the
hinge, then using a hard solder will be equally necessary to attach
the hinge sections ( presuming you are going to attach the outer
tubing first then saw out sections to attach to the other side of
the piece) that matches the colour of the metal(s) so keep that in
mind when ordering anything other than silver from vendors you don’t
normally use as most often colours don’t match from vendor to
vendor…

let me know if i can help further… regards, rer


#9

Hi Judy, I have some tubing that is very close (walls maybe not quite
that thick) that I got from Hoover and Strong, or possibly Myron
Toback. Sorry I can’t be more specific, and worse I have no idea what
their inventory on tubing is like at either place at the moment. It’s
worth a look since they both have toll free numbers.

Thomas III


#10

Hello Judy, Plug one end of tubing that is larger than you need with
a bit of wire 6mm long of the same metal as the tubing. The tubing
should be 3 times the desired diameter. The end can now be tapered to
fit into a draw plate far enough for you to grab it. The wall will
get thicker as youdraw it down. Tubing pulls much easier than
solid wire. I’ve done this many times. Have fun. Tom Arnold


#11

Judy,

You’re almost there with your tubing. Start with a larger diameter
tubing than what you need, and using a metal drawplate and a draw
bench, draw the tubing down to the diameter you need. The walls will
thicken the more you draw it down. Your tubing will stay round on
the interior. A “draw dog” is needed to solder into the end of the
tube, which matches up to the outer diameter of the tube being drawn.
The other end of the "dog"needs to come to a long, slender taper,
which is what you will grab onto to pull your tubing through the
holes in the drawplate.

Your drawplate will need to go large enough to accommodate your
tubing.

–Jay Whaley


#12

Hi again Judy,

The more I think about this, the more I think brute force may be the
right answer.

I think I remember seeing at least one lathe, maybe two or three
hidden away over on your husband’s side of the shop? If any of them
take collets, you’re golden. (and I think the big one does?) Collets
of the proper ID can be had cheaply, or just get an emergency collet,
and drill+ream it out to the right size.

Then slap a slug of solid rod of proper OD in there, and drill it
out. For hinge knuckles, that’ll probably be quicker and less painful
than horsing around trying to custom draw a tube. Yes, you lose some
of the chips to the lathe gods, but it’s probably cheaper once you
count your time. Besides, that way you can face the knuckles to be
perfectly square, and the exact proper length as well.

Remember to check the alignment of the tailstock before you start
drilling. It’s possible for the tailstock to be offset to either
side. For most turning and drilling, most of the time, it doesn’t
really matter much, but for tiny drills, it matters a lot that they
be exactly on center.

Regards,
Brian


#13

Hi Judy

Firstly do you have a 3mm to 0.5mm drawplate? If not you would need
to buy one, buy a tungsten carbide drawplate as it will last you for
ever and not rust.

Hard wood might be alright for very large holes but would not be
strong enough to give you the accuracy you require.

You also need to buy lengths of piano wire of the appropriate
diameters for your internal diameters. There is American piano wire,
about.9mm and about 1.1, they are imperial or inch measurements. And a
waxy lubricant, I use ‘easy lube’

If you can buy silver tube, say, 3mm and anneal it then taper the
end, say, 2cms ‘crudely’ in the square rolling mills so it will fit
through the appropriate hole in the drawplate.

Heavily wax the thicker wire and push into the tube as far it will
go.

You will need a drawbench to draw the tube down to fit tightly to
the wire. Draw the tube down, making sure the wire is fully in the
tube, until the wax is forced out of the open end. Reverse the tube
and put the end of the protruding wire through the smallest hole
possible in the draw plate and grip in the draw tongs and pull the
wire out of the tube.

You can find details for making a drawbench on my blog on Ganoksin
"On Your Metal" or "dropbox’ or Google “Drive”

Hope this has been of use.
David Cruickshank (Australia)
jewellerydavidcruickshank.com.au


#14

Hi

I trained as a box maker/silversmith here in the UK and was shown
how to make heavy walled tubing for both standard hinges and cut
flush hinges.

It’s a simple process which I have used many times and I normally
start with a piece of suitable commercial tubing 4.75mm outside
diameter, 1.25mm inside diameter and a wall thickness of 1.5mm and a
piece of polished steel wire of the same thickness as the hinge pin
you intend to use [0.7 to 0.9mm].

I usually start with say 100mm of tube[ 4 inches] long and a piece
of wire some three times that length.

Fully anneal the tubing and run a small amount of candle wax into
the still warm tube until you see it run out the other end. Insert
the wire with say 25mm[1 inch] showing at the selected lead end.
Crush/crimp the tubing onto the lead end wire to hold it in place. I
ram it into the wire grooves in the rolling mill which had the added
benefit of making a lead taper on the tube.

Now use a draw bench and draw plates to reduce the tubing to the
required diameter, in my case its normally 3mm OD with a.9mm hinge
wire. It’s hard work unless you have a geared draw bench but its
manageable.

As the tubing is reduced by the ever decreasing draw plates
diameters the tube firstly reduces its internal diameter until it
meets the inserted wire, then it starts to get longer and so an
initial tube length of 100mm may be at least twice that length when
you get to the correct diameter. It gets easier as you near the
correct size.

Once you have the correct OD remove and reverse the tubing in the
draw bench and using a reversed draw plate, flat side towards the
tubing, with a diameter sufficient just to allow the wire to pass,
draw the wire out of the tube. The candle wax helps with this
process. Stainless steel wire can break so standard polished steel
wire[ piano wire ] is the best choice.

Placing the hinge in the correct position is very important and is
particularly difficult for flush hinges

Regards
Mike Kersley
Hertfordshire UK


#15
Start with a larger diameter tubing than what you need, and using a
metal drawplate and a draw bench, draw the tubing down to the
diameter you need. The walls will thicken the more you draw it
down. 

Seriously take a piece of tubing and measure the wall thickness and
then draw it down by a factor of 3 from the original OD and measure
the thickness again. It will be only a tiny bit thicker. There is
very little gain in wall thickness It may appear thicker because of
the change in diameter changes the aspect ratio of the diameter to
the wall but the thickness of the wall is hardly affected by drawing.

James Binnion
James Binnion Metal Arts


#16

Hi Judy, I have seen this small size for sale at Metalliferous.

Vera
galleryvera.com


#17

gary snyder jewelry artist has a video on making tubing how to
calculate how to dap it how to draw it down. you can’t use websites
on Ganoksin so i’ll write it out long way
http://www.ganoksin.com/gnkurl/ep7zo7

sabra


#18

Hi Judy,

You can certainly make your own tubing. It’s not really a daunting
task, and you will always have the right size on hand! You can draw
down commercial tubing by soldering a bit of wire that fits the ID of
the tubing, long enough to file a taper for starting through the draw
plate. Yes, the ID of the tubing will become smaller and your walls
thicker as you draw it down, but if you want to retain a certain
diameter inside, you can insert the same size wire into the tube
before you draw, and the tube will become longer, with a thinner
diameter wall. You can start with a narrow strip of sheet, and make
it completely from start to finish if you are looking for specific
alloys not readily available. You can solder the tubing when
complete, and lay the seam facedown when you solder it to your
project.

Brepohl has a thorough description in The Theory and Practice of
Goldsmithing. Alan Revere’s Professional Goldsmithing also has a
pictorial showing some of the various steps. “Metalsmith Suite”, a
wonderful metalsmiths app by Tim McCreight, has a section that will
give you the starting width of sheet, when you plug in the sheet
thickness and the desired OD. I pull tubing by hand, my drawplate in
a small bench vise, and my foot propped against my bench. I’m
ususally making short lengths, 6 inches or less, for specific
projects, and always have extra bits laying around which come in
handy.

Have fun!
Melissa Veres, engraver


#19

The magnitudes of wall thickness increase and tube elongation depend
on the flow stress (a physical property of the metal or alloy) of the
drawn part, drawing die geometry, and friction between the drawing
die and the tube. The thickening will chance with the amount of
reduction and the aspect ratio of the wall to tube diameter. You can
actually have a wall thickness decrease in certain conditions. Again
it is best to be very near the desired wall thickness when drawing
tube rather than rely on thickening from drawing.

For some info on drawing tubing and wall thickness change this link
has some data.

http://www.ganoksin.com/gnkurl/ep7zo9

James Binnion
James Binnion Metal Arts