I need to cut up a 6" HDPE tube with square ends. So I'm thinking of
mounting it on my lathe with cones to center the tube and keep the cuts
square.

The problem is I can see how to turn a cone (or at least truncated cones
for this large of piece) that will mount to the headstock but not sure
how to keep a cone straight when held in place on the tailstock. Yes I
know the pressure will hold it in place but this tube is 36" long and I
can see problems trying to keep the whole mess in alingment while trying
to tighten the tailstock.

I'm thinking of drilling several inches into "face" of the cone with the
Jacobs chuck while the cone is still unfinished and still mounted to the
headstock. Then when I mount that cone on the tailstock run a steel rod
through the tailstock in hopes that would help stabilize the alignment.
The rod OD would have to be the same as the tailstock tunnel's ID to
reduce the slop.

Anybody had experience using large cones to center tubes?

Make a morse taper on the opposite side of the wood from your cone section
and stick that into the morse taper in your tailstock. The cone is
perfectly centered in your tailstock. I use cones all the time to center
pieces either for reverse chucking (using it in the headstock) and when I
predrill something like a vase (using it in the tailstock). The Oneway
tailcenter has a large cone but sometimes it's just not big enough.

- Andrew



"Terry Clark" wrote in message
...
I need to cut up a 6" HDPE tube with square ends. So I'm thinking of
mounting it on my lathe with cones to center the tube and keep the cuts
square.

The problem is I can see how to turn a cone (or at least truncated cones
for this large of piece) that will mount to the headstock but not sure
how to keep a cone straight when held in place on the tailstock. Yes I
know the pressure will hold it in place but this tube is 36" long and I
can see problems trying to keep the whole mess in alingment while trying
to tighten the tailstock.

I'm thinking of drilling several inches into "face" of the cone with the
Jacobs chuck while the cone is still unfinished and still mounted to the
headstock. Then when I mount that cone on the tailstock run a steel rod
through the tailstock in hopes that would help stabilize the alignment.
The rod OD would have to be the same as the tailstock tunnel's ID to
reduce the slop.

Anybody had experience using large cones to center tubes?

"AHilton" wrote: Make a morse taper on the opposite
side of the wood from your cone section and stick that into the morse taper
in your tailstock.(clip)
^^^^^^^^^
Is it Terry's intention to have the tube spinning in the lathe? That would
require a live center type support for the tailstock cone. I can picture
the smoke coming from the above setup. :-)

Leo Lichtman wrote:

"AHilton" wrote: Make a morse taper on the opposite
side of the wood from your cone section and stick that into the morse taper
in your tailstock.(clip)
^^^^^^^^^
Is it Terry's intention to have the tube spinning in the lathe? That would
require a live center type support for the tailstock cone. I can picture
the smoke coming from the above setup. :-)


Use a Jacobs chuck with the original hole and rod.
Just wax the rod and put a washer between the Jacobs Chuck and the cone.
Should get by at slow speeds. I don't think the morse taper is a good idea.

--

Gerald Ross, Cochran, GA
To reply add the numerals "13" before the "at"
............................................
Never use a preposition to end a
sentence with.




-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

Oops. You're right Leo. I was thinking of my setup here with a live morse
taper adapter that I just keep in there and forgot about. If you don't have
such an adapter it would certainly smoke something up. g

- Andrew



"Leo Lichtman" wrote in message
...

"AHilton" wrote: Make a morse taper on the
opposite
side of the wood from your cone section and stick that into the morse
taper
in your tailstock.(clip)
^^^^^^^^^
Is it Terry's intention to have the tube spinning in the lathe? That
would
require a live center type support for the tailstock cone. I can picture
the smoke coming from the above setup. :-)

Hi Terry,
Would the smoke & stench matter much if you use a waxed or otherwise
slicked dead tail cone with Andrew's taper and sacrificed a bit of the
tube's end? Would a steady rest help to keep this long tube centered?

I assume you plan to cut the long tube into several segments and I
wonder if a lathe is the best tool for cutting this size tube. How
about bandsawing using a fine tooth blade cutting thru a cross kerf in a
V-sled? Could you dress the tube ends by holding squarely against a
fine grit sanding disc or rubbing plate? You might just want to part
off something on your lathe, if so ignore all this. Arch

Fortiter,

I've done it with just a high fence on the miter gage with my bandsaw.
Stinks, but makes accurate cuts when fed slowly.

"Arch" wrote in message
...
How
about bandsawing using a fine tooth blade cutting thru a cross kerf in a
V-sled? Could you dress the tube ends by holding squarely against a
fine grit sanding disc or rubbing plate? You might just want to part
off something on your lathe, if so ignore all this. Arch

Fortiter,

Terry, suggest you make the head stock cone with a tenon to mount in your
favorite chuck. Make the tail stock cone with a flat outer face, more or
less, with an accurate center hole in it. Mount the head stock center cone,
place the tube against it, put the tail stock cone into the tube and bring
up the tailstock/live center and snug it to the amount required. Should
center up nicely.

Terry Clark wrote:

I need to cut up a 6" HDPE tube with square ends. So I'm thinking of
mounting it on my lathe with cones to center the tube and keep the cuts
square.

The problem is I can see how to turn a cone (or at least truncated cones
for this large of piece) that will mount to the headstock but not sure
how to keep a cone straight when held in place on the tailstock. Yes I
know the pressure will hold it in place but this tube is 36" long and I
can see problems trying to keep the whole mess in alingment while trying
to tighten the tailstock.

I'm thinking of drilling several inches into "face" of the cone with the
Jacobs chuck while the cone is still unfinished and still mounted to the
headstock. Then when I mount that cone on the tailstock run a steel rod
through the tailstock in hopes that would help stabilize the alignment.
The rod OD would have to be the same as the tailstock tunnel's ID to
reduce the slop.

Anybody had experience using large cones to center tubes?

Hi Terry

If I had to do what (I think) you want to do, I would turn 2 plugs that
fit into your tube, one would go into your chuck and the other one would
have your live center of your tailstock go into it.

and get a block plus a wedge to hold your tube up while you get your
tailstock in place

you can taper the edge of the plug so that it is easier to insert the
plug into the tube

(if this comes over right) your plug should look something like this
___
________| |
| |
| |
| |
| |
|________ |
|__|

hope this helps!

Have fun and take care
Leo Van Der Loo


Terry Clark wrote:
I need to cut up a 6" HDPE tube with square ends. So I'm thinking of
mounting it on my lathe with cones to center the tube and keep the cuts
square.

The problem is I can see how to turn a cone (or at least truncated cones
for this large of piece) that will mount to the headstock but not sure
how to keep a cone straight when held in place on the tailstock. Yes I
know the pressure will hold it in place but this tube is 36" long and I
can see problems trying to keep the whole mess in alingment while trying
to tighten the tailstock.

I'm thinking of drilling several inches into "face" of the cone with the
Jacobs chuck while the cone is still unfinished and still mounted to the
headstock. Then when I mount that cone on the tailstock run a steel rod
through the tailstock in hopes that would help stabilize the alignment.
The rod OD would have to be the same as the tailstock tunnel's ID to
reduce the slop.

Anybody had experience using large cones to center tubes?

having attempted this a few times, let me humbly suggest that you make a
mandril that fits snugly inside the tube rather than the cones - I can think
of several ways to do this, but start with some MDF (or other scrap) disks -
3 or 4 of them, space out with scrap lumber, drill through for a rod (use
water pipe maybe), then slide the tube over it and put the whole mess on the
late - that way when you cut the tube it won't collapse on you
"Terry Clark" wrote in message
...
I need to cut up a 6" HDPE tube with square ends. So I'm thinking of
mounting it on my lathe with cones to center the tube and keep the cuts
square.

The problem is I can see how to turn a cone (or at least truncated cones
for this large of piece) that will mount to the headstock but not sure
how to keep a cone straight when held in place on the tailstock. Yes I
know the pressure will hold it in place but this tube is 36" long and I
can see problems trying to keep the whole mess in alingment while trying
to tighten the tailstock.

I'm thinking of drilling several inches into "face" of the cone with the
Jacobs chuck while the cone is still unfinished and still mounted to the
headstock. Then when I mount that cone on the tailstock run a steel rod
through the tailstock in hopes that would help stabilize the alignment.
The rod OD would have to be the same as the tailstock tunnel's ID to
reduce the slop.

Anybody had experience using large cones to center tubes?

Thanks for all the replies!

William, I like your idea best. Not so much because of the collapse problem, I
was not going to cut all the way through the tube but save the final cut for a
hand saw - like any parting off. Any "fringe" will be sanded off.

But by using your plan I can make use of that piece of closet rod I have kicking
around (it doesn't even need to be a full 36" long.) I'll be able to hold it in
place with my large Oneway live center in the tailstock. I'll true up the rod,
measure the diameter and cut holes in the spacer discs to fit over the rod.
After they are glued in place I can true up and adjusted the discs' diameter to
the ID of the HDPE. The tube should fit snuggly over the mandrel and if it slips
slightly while turning I can put a wedge between the disc and the tube. That way
I don't have the problem of a wobbly tail piece and I can also cut all the way
through!

In case anyone is interested in why I want to turn this stuff: I'm also a
pyrotechnician and I'm building a ball mill. The short (~11.5") segments of the
HDPE tube will have lids fitted to the ends and will function as milling bottles
with 3/4" lead plugs inside grinding chemicals for my pyro work. Only one tube
will be cut into 3 "bottles", 3 other tubes will have only one segment removed.
That will give me 3 bottle sets (use 2 at a time.) That way each set can be
devoted to tumbling only certain chemicals and avoid cross contamination. The 3
tubes that will be left at 24" long will be used to fire mines instead of
regular aerial shells.

All these will require more lathe work since the end caps for the bottles will
need to be a snug fit and the mine tubes will need wood end plugs. There is a
lot of things you can do with a lathe besides bowls!

Thanks again

Terry,

william_b_noble wrote:

having attempted this a few times, let me humbly suggest that you make a
mandril that fits snugly inside the tube rather than the cones - I can think
of several ways to do this, but start with some MDF (or other scrap) disks -
3 or 4 of them, space out with scrap lumber, drill through for a rod (use
water pipe maybe), then slide the tube over it and put the whole mess on the
late - that way when you cut the tube it won't collapse on you
"Terry Clark" wrote in message
...
I need to cut up a 6" HDPE tube with square ends. So I'm thinking of
mounting it on my lathe with cones to center the tube and keep the cuts
square.

The problem is I can see how to turn a cone (or at least truncated cones
for this large of piece) that will mount to the headstock but not sure
how to keep a cone straight when held in place on the tailstock. Yes I
know the pressure will hold it in place but this tube is 36" long and I
can see problems trying to keep the whole mess in alingment while trying
to tighten the tailstock.

I'm thinking of drilling several inches into "face" of the cone with the
Jacobs chuck while the cone is still unfinished and still mounted to the
headstock. Then when I mount that cone on the tailstock run a steel rod
through the tailstock in hopes that would help stabilize the alignment.
The rod OD would have to be the same as the tailstock tunnel's ID to
reduce the slop.

Anybody had experience using large cones to center tubes?