Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

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Posted to rec.crafts.metalworking
Roy
 
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Default Cutting threads on the inside of a 3" socket end of PVC pipe

I am in the process of making an item for my sal****er setups, and
have to thread the inside diam of a 3" socket joint (happens to be
correct bore needed for my application and only needs threads) which
are 13 tpi. My biggest problem is if I tighten the piece up in the
chuck it distorts it. I ruined a bunch of pieces trying to find a
sweet spot n chucking prressure with out distortin oor without having
it slip. Even with light cuts its gone wrong. Perhaps I need to put it
all away and give it a try on anaother day, unless someone can suggest
something that may work to hold this piece in the chuck without
distortion or slipping. I have played with super glueiing it, double
faced tapes, but one thing I have not tried net is to glue two or
three lugs on the outside of the piece I am turning and allow them to
hold against the chuck jaws sides.........hmmmmmmmthat idea just hit
me, is there anything else that may work?

PVC is neat to machine, but it can get awfull flimsey and such when
chucked up.....
--
\\\|///
( @ @ )
-----------oOOo(_)oOOo---------------


oooO
---------( )----Oooo----------------
\ ( ( )
\_) ) /
(_/
The original frugal ponder! Koi-ahoi mates....
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Default Cutting threads on the inside of a 3" socket end of PVC pipe

Suggestions, I haven't tried 'em:

Cut a short length of Sched 40 or thicker 3" pipe to go in the opposite
end of the joint. Now the wall thickness is almost doubled, and should
not distort quite so much.

Drill holes into the opposite end of the joint and drive small screws
into them. With those screw heads sticking up, the piece shouldn't
rotate in the chuck.

or....do both of the above.

Best -- Terry

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RoyJ
 
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Default Cutting threads on the inside of a 3" socket end of PVC pipe

BTDT: PVC is pretty flimsy stuff. I'd solvent glue it to a 1/2" pvc
plate, chuck up the plate, turn the threads, cut it off. Of course, I
have some PVC sheet stock available so that is the first choice.

Roy wrote:
I am in the process of making an item for my sal****er setups, and
have to thread the inside diam of a 3" socket joint (happens to be
correct bore needed for my application and only needs threads) which
are 13 tpi. My biggest problem is if I tighten the piece up in the
chuck it distorts it. I ruined a bunch of pieces trying to find a
sweet spot n chucking prressure with out distortin oor without having
it slip. Even with light cuts its gone wrong. Perhaps I need to put it
all away and give it a try on anaother day, unless someone can suggest
something that may work to hold this piece in the chuck without
distortion or slipping. I have played with super glueiing it, double
faced tapes, but one thing I have not tried net is to glue two or
three lugs on the outside of the piece I am turning and allow them to
hold against the chuck jaws sides.........hmmmmmmmthat idea just hit
me, is there anything else that may work?

PVC is neat to machine, but it can get awfull flimsey and such when
chucked up.....

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Posted to rec.crafts.metalworking
Roy
 
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Default Cutting threads on the inside of a 3" socket end of PVC pipe

I have a limited uspply of sheet pvc (1/4") and had considered doing
this, but was a bit leary of cutting up the sheetstock and then screw
up cutting the threads.....
What I am making is a retaining ring that has a flange on it so it can
clamp a funnel shapped cup to a flange with an O-ring seal between the
two.

I happened on a few items called protein skimmers that leaked at the
adjustment knob shaft, and figured out a way to cut that apart and
remachine the shaft and housing to include a o-ring seal like later
models have, unfortunately when the company threw out these leaking
skimmers on warranty replacement they retained the colleciton cups and
pumps. The going price for a replacement cup complete with retaining
ring is $48.90 each.......and that does not include the cap for the
cup, which would be a piece of cake to make once I get the cup and
retaining ring made.....so is life.....Pumps I have , so I can save a
lot of $$$$ if I can get the retaining rings made. I also need to find
the name of a plastic, which is described in another post.
Regards


On Sun, 22 Jan 2006 23:08:00 GMT, RoyJ wrote:
BTDT: PVC is pretty flimsy stuff. I'd solvent glue it to a 1/2" pvc
plate, chuck up the plate, turn the threads, cut it off. Of course, I
have some PVC sheet stock available so that is the first choice.

Roy wrote:
I am in the process of making an item for my sal****er setups, and
have to thread the inside diam of a 3" socket joint (happens to be
correct bore needed for my application and only needs threads) which
are 13 tpi. My biggest problem is if I tighten the piece up in the
chuck it distorts it. I ruined a bunch of pieces trying to find a
sweet spot n chucking prressure with out distortin oor without having
it slip. Even with light cuts its gone wrong. Perhaps I need to put it
all away and give it a try on anaother day, unless someone can suggest
something that may work to hold this piece in the chuck without
distortion or slipping. I have played with super glueiing it, double
faced tapes, but one thing I have not tried net is to glue two or
three lugs on the outside of the piece I am turning and allow them to
hold against the chuck jaws sides.........hmmmmmmmthat idea just hit
me, is there anything else that may work?

PVC is neat to machine, but it can get awfull flimsey and such when
chucked up.....


--
\\\|///
( @ @ )
-----------oOOo(_)oOOo---------------


oooO
---------( )----Oooo----------------
\ ( ( )
\_) ) /
(_/
The original frugal ponder! Koi-ahoi mates....


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Bob AZ
 
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Default Cutting threads on the inside of a 3" socket end of PVC pipe

Roy
I am not sure I understand exactly what you want to do but get a larger
piece of PVC that will not distort as easily. The bore it to fit your
flimsy stock. Glue it in if needed. Then thread away and cut away the
bad from the good.

Bob AZ

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John
 
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Default Cutting threads on the inside of a 3" socket end of PVC pipe

Roy wrote:

I have a limited uspply of sheet pvc (1/4") and had considered doing
this, but was a bit leary of cutting up the sheetstock and then screw
up cutting the threads.....
What I am making is a retaining ring that has a flange on it so it can
clamp a funnel shapped cup to a flange with an O-ring seal between the
two.

I happened on a few items called protein skimmers that leaked at the
adjustment knob shaft, and figured out a way to cut that apart and
remachine the shaft and housing to include a o-ring seal like later
models have, unfortunately when the company threw out these leaking
skimmers on warranty replacement they retained the colleciton cups and
pumps. The going price for a replacement cup complete with retaining
ring is $48.90 each.......and that does not include the cap for the
cup, which would be a piece of cake to make once I get the cup and
retaining ring made.....so is life.....Pumps I have , so I can save a
lot of $$$$ if I can get the retaining rings made. I also need to find
the name of a plastic, which is described in another post.
Regards

On Sun, 22 Jan 2006 23:08:00 GMT, RoyJ wrote:
BTDT: PVC is pretty flimsy stuff. I'd solvent glue it to a 1/2" pvc
plate, chuck up the plate, turn the threads, cut it off. Of course, I
have some PVC sheet stock available so that is the first choice.

Roy wrote:
I am in the process of making an item for my sal****er setups, and
have to thread the inside diam of a 3" socket joint (happens to be
correct bore needed for my application and only needs threads) which
are 13 tpi. My biggest problem is if I tighten the piece up in the
chuck it distorts it. I ruined a bunch of pieces trying to find a
sweet spot n chucking prressure with out distortin oor without having
it slip. Even with light cuts its gone wrong. Perhaps I need to put it
all away and give it a try on anaother day, unless someone can suggest
something that may work to hold this piece in the chuck without
distortion or slipping. I have played with super glueiing it, double
faced tapes, but one thing I have not tried net is to glue two or
three lugs on the outside of the piece I am turning and allow them to
hold against the chuck jaws sides.........hmmmmmmmthat idea just hit
me, is there anything else that may work?

PVC is neat to machine, but it can get awfull flimsey and such when
chucked up.....


--
\\\|///
( @ @ )
-----------oOOo(_)oOOo---------------

oooO
---------( )----Oooo----------------
\ ( ( )
\_) ) /
(_/
The original frugal ponder! Koi-ahoi mates....



Make a ring of steel, aluminum or any other material that the pipe will
just slide into the bored hole. cut a slot in the ring so that when
the chuck jaws close on the ring there is enough gap that the ring will
grab the pipe tightly.
I have used this method on thin wall parts many times. It works.



John
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Harold and Susan Vordos
 
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Default Cutting threads on the inside of a 3" socket end of PVC pipe


"Roy" wrote in message
...
I am in the process of making an item for my sal****er setups, and
have to thread the inside diam of a 3" socket joint (happens to be
correct bore needed for my application and only needs threads) which
are 13 tpi. My biggest problem is if I tighten the piece up in the
chuck it distorts it. I ruined a bunch of pieces trying to find a
sweet spot n chucking prressure with out distortin oor without having
it slip. Even with light cuts its gone wrong. Perhaps I need to put it
all away and give it a try on anaother day, unless someone can suggest
something that may work to hold this piece in the chuck without
distortion or slipping. I have played with super glueiing it, double
faced tapes, but one thing I have not tried net is to glue two or
three lugs on the outside of the piece I am turning and allow them to
hold against the chuck jaws sides.........hmmmmmmmthat idea just hit
me, is there anything else that may work?

PVC is neat to machine, but it can get awfull flimsey and such when
chucked up.....


Roy,
This is an excellent place for soft jaws. If you make some jaws that are
broad enough, they'll enclose the piece almost totally, eliminating
distortion. It's worth the effort, for then you'll have the jaws for other
applications, and you'll be surprised at how often you'll use them once you
have them. Nice part is you'll be able to take the piece out and put it
back and have it run nearly perfectly. The advantages of soft jaws are
almost endless.

Harold


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Eric R Snow
 
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Default Cutting threads on the inside of a 3" socket end of PVC pipe

On Sun, 22 Jan 2006 22:34:49 GMT, (Roy) wrote:

I am in the process of making an item for my sal****er setups, and
have to thread the inside diam of a 3" socket joint (happens to be
correct bore needed for my application and only needs threads) which
are 13 tpi. My biggest problem is if I tighten the piece up in the
chuck it distorts it. I ruined a bunch of pieces trying to find a
sweet spot n chucking prressure with out distortin oor without having
it slip. Even with light cuts its gone wrong. Perhaps I need to put it
all away and give it a try on anaother day, unless someone can suggest
something that may work to hold this piece in the chuck without
distortion or slipping. I have played with super glueiing it, double
faced tapes, but one thing I have not tried net is to glue two or
three lugs on the outside of the piece I am turning and allow them to
hold against the chuck jaws sides.........hmmmmmmmthat idea just hit
me, is there anything else that may work?

PVC is neat to machine, but it can get awfull flimsey and such when
chucked up.....

You can make "pie jaws" for your chuck. These are shaped like sections
of a pie. Use sections that are 120 degrees. Close them until the
sides almost touch and then bore to fit your part. These will hold
your parts with small enough distortion, and with enough grip, to
single point your threads. Another method would be to turn and bore a
piece of good wood (not pine, but maybe poplar?) so that your part
just slips into the wood piece. Make one saw cut so that the wood can
grip the plastic when the chuck jaws tighten. A 3/4" wall on the wood
piece should be adequate. If slippage does occur then glue some fine
sandpaper to the wood in the bore. 320 or 240 grit would work fine.
ERS


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Jon Elson
 
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Default Cutting threads on the inside of a 3" socket end of PVC pipe

Roy wrote:
I am in the process of making an item for my sal****er setups, and
have to thread the inside diam of a 3" socket joint (happens to be
correct bore needed for my application and only needs threads) which
are 13 tpi. My biggest problem is if I tighten the piece up in the
chuck it distorts it. I ruined a bunch of pieces trying to find a
sweet spot n chucking prressure with out distortin oor without having
it slip. Even with light cuts its gone wrong. Perhaps I need to put it
all away and give it a try on anaother day, unless someone can suggest
something that may work to hold this piece in the chuck without
distortion or slipping. I have played with super glueiing it, double
faced tapes, but one thing I have not tried net is to glue two or
three lugs on the outside of the piece I am turning and allow them to
hold against the chuck jaws sides.........hmmmmmmmthat idea just hit
me, is there anything else that may work?

PVC is neat to machine, but it can get awfull flimsey and such when
chucked up.....


Make a custom "collet" for it. Hopefully, these parts are
quite cylindrical (probably so if you were chucking them).
So, you get a piece of pipe, aluminum or steel, that has a
slightly smaller ID than the PVC part's OD. Turn in the
lathe until the PVC part is a very tight press fit in the
ring. Then, slit the ring at one point and clean up the
edges. When you put the PVC part in the ring, and then
clamp the ring in the 3-jaw, it will close up the slit
and grip the part. If the ring is stronger than the PVC
it will distort much less, and put the PVC part in
circumferential stress, so as to minimize distortion.
The PVC part would bulge out between the chuck jaws without
this ring. I've made this sort of fixture a number of times
when turning flimsy parts, and it has never failed to fix
the problem.

Jon

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Rick
 
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Default Cutting threads on the inside of a 3" socket end of PVC pipe


"Roy" wrote in message
...
I am in the process of making an item for my sal****er setups, and
have to thread the inside diam of a 3" socket joint (happens to be
correct bore needed for my application and only needs threads) which
are 13 tpi. My biggest problem is if I tighten the piece up in the
chuck it distorts it. I ruined a bunch of pieces trying to find a
sweet spot n chucking prressure with out distortin oor without having
it slip. Even with light cuts its gone wrong. Perhaps I need to put it
all away and give it a try on anaother day, unless someone can suggest
something that may work to hold this piece in the chuck without
distortion or slipping. I have played with super glueiing it, double
faced tapes, but one thing I have not tried net is to glue two or
three lugs on the outside of the piece I am turning and allow them to
hold against the chuck jaws sides.........hmmmmmmmthat idea just hit
me, is there anything else that may work?

PVC is neat to machine, but it can get awfull flimsey and such when
chucked up.....



I'd suggest you measure the ID of your socket and the OD of any PVC pipe you decide to use
in a few places first. If it's anything like the 4" piece I used to make a housing a while
back, it ain't round to start out with. I ended up turning a wood plug as a pilot.

You may want to get a cleanout adapter to slip inside or over the piece you're threading
and work from there...




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Bugs
 
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Default Cutting threads on the inside of a 3" socket end of PVC pipe

Turn a wood plug that will drive into the pipe. It will stiffen the
pipe enough to hold in the chuck.
Bugs

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Roy
 
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Default Sucess sort of, was Cutting threads on the inside of a 3" socket end of PVC pipe

Well I took a different approach.I first started with PVC pipe
fittings as they were close to being what I needed, and would work if
I pursued it with a proper method of retaiing the piece in the chuck.

What I did was laminate two pieces of 1/2" pvc sheet stock together. I
made them 4 1/2" square. Mounted it in a 4 jaw, cut the center out
roughly with a hole saw mounted in the tailstock, cleaned up the hole
to required ID, cut the threads and shoulder lip it needed, removed
the piece and remounted it in a 3 jaw with the jaws holding the work
internally and machined off the outer portion to obtain the round
shape and ran a light knurl on it as well..... Looks great......I
guess using an already produced form or shape is not always the
easiest route to go. It took far less and lots less waste overall
doing it this way than it did my old way and getting nowhere...
--
\\\|///
( @ @ )
-----------oOOo(_)oOOo---------------


oooO
---------( )----Oooo----------------
\ ( ( )
\_) ) /
(_/
The original frugal ponder ! Koi-ahoi mates....
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Bob Engelhardt
 
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Default Sucess sort of, was Cutting threads on the inside of a 3" socketend of PVC pipe

Roy wrote:

......I
guess using an already produced form or shape is not always the
easiest route to go. It took far less and lots less waste overall
doing it this way than it did my old way and getting nowhere...


Oh, that's familiar. There's an approach that looks very promising, but
after adjusting and/or fixing one complication after another, you
realize that a whole-other approach is really called for. The new way
usually turns out to be as good or better. Bob
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