Standards for threaded pipe exist up to 24 inches.? The largest I've
seen is around 12 inches but 6-8 isn't uncommon.?? I have no
idea how they applied the torque to make these up.? Of course,
modern practice would use a grooved system like "Victaulic," or
welding.?? (I have a five or six foot pipe tong (chain wrench)
that I keep around for some reason.? I can barely pick it
up.)
At one time houses were plumbed with threaded galvanized pipe, but those
days are long gone, at least in the US.? Gas pipe is still commonly
threaded "black" steel but it seems corrugated stainless is
taking over that market.? Electricians do some threading of heavy
wall conduit.
So it seems that pipe threading is becoming somewhat
obsolescent.
I cut and thread pipe a few times a year--usually gas pipe or when piping
up a boiler.? The tools are expensive new but easy enough to find at
flea markets, etc.? To do it in the traditional way you need a pipe
vise of some sort--I like the chain type as being less in the way--a pipe
cutter--a hacksaw works--a reamer--filing works in a pinch--and
dies/stocks, which come in different sorts.
Threading is a really lousy way to put up something like a flagpole, or
to contain high pressures under vibration, as the threads thin the pipe
wall and create places for circumferential fatigue cracks to
start.
At 05:42 AM 11/12/2012 -0500, you wrote:
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Show quoted text
?
The famous Model T Ford had 1/2" pipe threaded sparkplugs. The
plumber's
diestock I have has 2' long handles on it, and is not at al hard to
turn.
Mert
-----Original Message-----
From:
7x12minilathe@...
[
mailto:7x12minilathe@...]On Behalf Of
fd042@...
Sent: Sunday, November 11, 2012 10:23 PM
To:
7x12minilathe@...
Subject: Re: [7x12minilathe] Re: Aside from pipes and camera cable
releases where else are tapered pipe threads used?
Old flywheel style single cylinder gasoline farm engines mostly used
1/2"
pipe threaded spark plugs. (Made after the low tention spark-points in
the
cylinder chamber, & before the high speed air cooled engines that
became
common after WWII) Tapered threads do not give a seal unless used with
pipe
dope or Teflon tape. (& other sealing methods I don't know about);
Regular
threading (no taper) up to a flange & gasket is the modern norm for
spark
plugs; the threads locate it, the flange & a gasket seals it. (&
you can use
dope/whatever on the threads to be really sure of a seal if you want.) I
am
not clear as to your need/use of tapered pipe threading...It is
traditional
for iron plumbing, cheap; & for installations that are
semi-permenant, IE
not have to be taken apart for a long time. Pipe thread taps & dies
work
with a straight pipe, both outside & inside size; IE no previous
taper
machining is needed. These taps & dies have their own built in taper,
& will
do the work themselves, albeit W/ a lot of effort, either by hand, or a
pipe
threading motor; but not a small lathe. Seems to me (here in Maine USA)
that
these threading procedures are better done by hand, with a die/ or tap,
&
only useing a lathe manually to mount/locate thease tools to get
better
accuracy.
-----Original Message-----
>From: Roy
>Sent: Nov 11, 2012 8:38 PM
>To:
7x12minilathe@...
>Subject: [7x12minilathe] Re: Aside from pipes and camera cable
releases
where else are tapered pipe threads used?
>
>With an OD of 5/16" it's 1/16" NPT. Both 1/16" &
1/8" NPT are 27 tpi.
>
>Straight pipe threads are used for electrical stuff; conduit fittings
are
threaded NPS as are lamp parts.
>
>Roy
>
>--- In
7x12minilathe@..., ToolRoomTrustee@... wrote:
>>
>>
>> Classical meter wheel and four dial counter blocks from
KAHLSICO.
>>
>> In my 28 year working life on National Oceanographic and
Atmospheric
Research ships as an oceanographic
>> technician I often had to deal with the devices that measured
amount of
cable going out (and hopefully coming back!).
>>
>> The technology of the times late 60s to mid 90s (in my career)
used a
stainless steel grooved wheel with a nominal circumference of
>> one meter that was suspended from a gantry or A-frame to allow
working
room for instrument packages. The wheel used a cable
>> similar to a speedometer cable to connect to a mechanical
contrivance
with four dials to cover units, tens, 100s and thousands of
>> meters. The meter wheel and four dial block used male threads
to
connect to female threads on end fittings of the connecting cable.
>> I was essentialy self taught on the job with my own Unimat at
first
then later got some end of fiscal year money to buy a Unimat for
>> my department. I determined that the threads were 5/16-24 which
is a
National Extra Fine so got a die and taps through govt supply
>> system. Much later found that it was actually a ?x27 pipe
thread. The
NEF tap did work.
>> My conjecture is that the NPT was used so the connections could
be put
on tight.
>>
>> Anyway, my query here is if anyone else has some examples of
where pipe
threads are used but not on pipes.
>>
>> Larry Murray
>>
>
>
>
>
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