I have to replicate some brass tubes that are used in a carburetor.
The tubes are .093 OD, and .015 wall. The original tubes are 2" long,
with the end .250 reduced down to .067 OD, which has an ID drilled and
sized to .030. I know that I could solder and drill the .093 tubing
and make it work, but I need to make this just like the OE tubing, so
I need to know if this is something I can do in my lathe? I need to
do about 25 of them for the first run.

If anyone can shed some light on this procedure, or has any positive
and helpful comments, please share!

wrote:
I have to replicate some brass tubes that are used in a carburetor.
The tubes are .093 OD, and .015 wall. The original tubes are 2" long,
with the end .250 reduced down to .067 OD, which has an ID drilled and
sized to .030. I know that I could solder and drill the .093 tubing
and make it work, but I need to make this just like the OE tubing, so
I need to know if this is something I can do in my lathe? I need to
do about 25 of them for the first run.

If anyone can shed some light on this procedure, or has any positive
and helpful comments, please share!

I couldnt answer IF you can do it in your lathe,
apart from turn it out of the solid.
Also I dont think I could do it in my lathe,
but I know I could do it in my draw bench.
this is 12ft long and will draw a 5ft length of material.
Its dated from about 1850 or so.
I drawn lots of tube down from big, ie 1/2 in down to 1/4, and 1/4in
down to 1/8in od.
when you draw metal through a die it is swaged down to the die size with
a thou or so of elastic respring.
If you drew some tube through a die of the right size then pulled it
back out, you then could cut out the bit you wanted.
In the older drawing process the drawtongs do crush the tube end so
that has to be cut off before it can be used as tube..
As an afterhought, you could turn up a mandrel to fit the internal
dimensions of the tube, over that an extenal steel tube to support it
lengththe same as the unswaged section. then make a die that you could
put on a drill press ,put the mandrel in the chuck, with the tube over
this then the collar over this. #
Hold in place and bring down the chuck to push the tube end into the die
to swage it down,
Use a bit of candle wax or oil as a lube.

I drawn lots of tube down from big, ie 1/2 in down to 1/4, and 1/4in
down to 1/8in od. When you draw metal through a die it is swaged down to the
die size with a thou or so of elastic respring. If you drew some tube through
a die of the right size then pulled it back out, you then could cut out the
bit you wanted.

In the older drawing process the drawtongs do crush the tube end...


How do you get the large tube trough the smaller die in the first place so the
jaws can grab it?

--
Dennis

You could resize the tube with a sizing die. This can be done in an arbor
press, but you may need to make several dies to reduce the diameter that
much. The die would be a hardened ring in a tube that you force down over
your tubing. The max squeeze per iteration would be about .020" The ring
should be kept as thin as possible in cross section to reduce friction. The
lube of choice would be lanolin. Pushing the ring onto the tube is easy, but
lifting the ring off the tube requires the tube and ring be held very
securely. Be sure to leave enough space in the die to allow the tube to grow
in length and it will do so substantially.
Steve

wrote in message
...
I have to replicate some brass tubes that are used in a carburetor.
The tubes are .093 OD, and .015 wall. The original tubes are 2" long,
with the end .250 reduced down to .067 OD, which has an ID drilled and
sized to .030. I know that I could solder and drill the .093 tubing
and make it work, but I need to make this just like the OE tubing, so
I need to know if this is something I can do in my lathe? I need to
do about 25 of them for the first run.

If anyone can shed some light on this procedure, or has any positive
and helpful comments, please share!

On Sat, 15 Dec 2007 23:05:10 -0800 (PST), wrote:

I have to replicate some brass tubes that are used in a carburetor.
The tubes are .093 OD, and .015 wall. The original tubes are 2" long,
with the end .250 reduced down to .067 OD, which has an ID drilled and
sized to .030. I know that I could solder and drill the .093 tubing
and make it work, but I need to make this just like the OE tubing, so
I need to know if this is something I can do in my lathe? I need to
do about 25 of them for the first run.

If anyone can shed some light on this procedure, or has any positive
and helpful comments, please share!

A sizing die might work, just like making little bitty wildcat
bottleneck brass cartridges -- 3 caliber! Might need two or three
dies.

For larger ID I would make a mandrel from drillrod, lube it with case
lube or lanolin. Make some smooth rollers for my scissors-type
knurler, perhaps with a taper on one side for the transition region.
Grab tube and mandrel in a collet, etc. But an .030 mandrel will flex
unless you can contrive a tailstock support of some sort, maybe a bit
of drillrod with a lubed .031" hole in it that goes in the tailstock
chuck.

You may need to anneal the tube before starting.

Let us know how you solve this one!

DT wrote:
I drawn lots of tube down from big, ie 1/2 in down to 1/4, and 1/4in
down to 1/8in od. When you draw metal through a die it is swaged down to the
die size with a thou or so of elastic respring. If you drew some tube through
a die of the right size then pulled it back out, you then could cut out the
bit you wanted.


In the older drawing process the drawtongs do crush the tube end...



How do you get the large tube trough the smaller die in the first place so the
jaws can grab it?


Make the tube smaller!!
Yes I know its a dumb answer but cant help myself .
So a serious answer, coming up.
you take the tube end, place in a hemispherical depression the tube
dia,flatten it down level, then take a round ended piece of steel, tap
it down on the flattened tube to make it concave.
Remove from the die block , place edge on flat metal anddress down to
close up the half round/concace tube end .
IE
Your folding it on itself, thus making it smaller.
Try it on some copper pipe, easy when youve done it once.

On Sun, 16 Dec 2007 12:05:03 -0600, Don Foreman
wrote:

On Sat, 15 Dec 2007 23:05:10 -0800 (PST), wrote:

I have to replicate some brass tubes that are used in a carburetor.
The tubes are .093 OD, and .015 wall. The original tubes are 2" long,
with the end .250 reduced down to .067 OD, which has an ID drilled and
sized to .030. I know that I could solder and drill the .093 tubing
and make it work, but I need to make this just like the OE tubing, so
I need to know if this is something I can do in my lathe? I need to
do about 25 of them for the first run.

If anyone can shed some light on this procedure, or has any positive
and helpful comments, please share!

A sizing die might work, just like making little bitty wildcat
bottleneck brass cartridges -- 3 caliber! Might need two or three
dies.

For larger ID I would make a mandrel from drillrod, lube it with case
lube or lanolin. Make some smooth rollers for my scissors-type
knurler, perhaps with a taper on one side for the transition region.
Grab tube and mandrel in a collet, etc. But an .030 mandrel will flex
unless you can contrive a tailstock support of some sort, maybe a bit
of drillrod with a lubed .031" hole in it that goes in the tailstock
chuck.

You may need to anneal the tube before starting.

Let us know how you solve this one!


The easy way is to take your basic copper tubing cutter, remove the
blade roller, replace with a smooth one wacked out on the lathe, then
simply spin the tubing, while tightening down the tubing cutter on the
tubing until you reach your reduced OD.

Quick, easy and repeatable.


Gunner

On Dec 16, 2:05 am, wrote:
I have to replicate some brass tubes that are used in a carburetor.
The tubes are .093 OD, and .015 wall. The original tubes are 2" long,
with the end .250 reduced down to .067 OD, which has an ID drilled and
sized to .030. I know that I could solder and drill the .093 tubing
and make it work, but I need to make this just like the OE tubing, so
I need to know if this is something I can do in my lathe? I need to
do about 25 of them for the first run.

I used to spin a reduced neck on 15/32" OD musical instrument tubing
in order to start it on the drawbench by annealing the last half inch,
putting it in a collete and cranking the back end of an old amstrong
toolholder into it. It worked, but it was a kind of dicey process.
Eventually switched to driving the ends through the full series of
draw rings using a rubber mallet. If driving, make absolelety sure to
anneal only the region you are working, or the whole tube will bend!

Don't know how well either process will work at reduced scale.

If you can get an end srunk down smaller than desired, you can try
putting it over a sizing mandrel with a step turned in it, and the
driving through a sacrificial die... used annealed fender washers to
make tapered french horn leadpipes that way. Problem with this method
is that it's very hard to get the washer-die off without drawing all
the way through, though if you made the step slightly more gradual
then you probably could pass the whole tube through it.