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If threaded steel pipe is used for gas, does that make houses safer? I live
in NYC, and a magazine story about the recent hurricane here said that house
fires spread in some neighborhoods because the heat of fires "melted" gas
pipes in the houses. Popular magazines aren't reliable on technical issues,
so I don't know if this was actually true, but if a house fire can get a gas
pipe hot enough to fail from heat, pipes should be made of steel or other
metal with a high melting point.

Mike Taglieri mailto:miket_nyc%40verizon.net

----- Original Message -----
From: "Alan Muller" <mailto:alan%40greendel.org>
To: <mailto:7x12minilathe%40yahoogroups.com>
Sent: Monday, November 12, 2012 11:41 AM
Subject: RE: [7x12minilathe] Re: Aside from pipes and camera cable releases
where else are tapered pipe threads used?

> 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:
>>
>>
>>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:
>>mailto:7x12minilathe%40yahoogroups.com
>>[mailto:mailto:7x12minilathe%40yahoogroups.com]On Behalf
>>Of mailto:fd042%40earthlink.net
>>Sent: Sunday, November 11, 2012 10:23 PM
>>To: mailto:7x12minilathe%40yahoogroups.com
>>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:
>> >mailto:7x12minilathe%40yahoogroups.com
>> >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
>> mailto:7x12minilathe%40yahoogroups.com,
>> 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
>> >>
>> >
>> >
>> >
>> >
>> >------------------------------------
>> >
>> >Yahoo! Groups Links
>> >
>> >
>> >
>>
>>
>