[gary]

I want to recharge the refrigerant in my auto air conditioner. I've
assembled all the necessary tools except for one item. My vacuum pump
is outfitted with a 3/4" female NPT fitting and the discharge tube
from the gauge set is a R134a female fitting. I plan on machining an
adapter to get the 2 fittings connected to each other.

But I can't figure out what the thread size is on the R134a. Please
enlighten me!


Gary

[Mark Simko]

"BQ340" wrote in message
...
gary wrote:
I want to recharge the refrigerant in my auto air conditioner. I've
assembled all the necessary tools except for one item. My vacuum pump
is outfitted with a 3/4" female NPT fitting and the discharge tube
from the gauge set is a R134a female fitting. I plan on machining an
adapter to get the 2 fittings connected to each other.

But I can't figure out what the thread size is on the R134a. Please
enlighten me!


Gary


1/2" Acme as I recall but I don't remember the pitch, sorry!

MikeB

1/2" - 16 Acme according to this chart

http://www.epa.gov/ozone/snap/refrig.../fittlist.html

[Bruce L. Bergman[_2_]]

On Sun, 14 Jun 2009 10:35:18 -0400, BQ340
wrote:

gary wrote:
I want to recharge the refrigerant in my auto air conditioner. I've
assembled all the necessary tools except for one item. My vacuum pump
is outfitted with a 3/4" female NPT fitting and the discharge tube
from the gauge set is a R134a female fitting. I plan on machining an
adapter to get the 2 fittings connected to each other.

But I can't figure out what the thread size is on the R134a. Please
enlighten me!

1/2" Acme as I recall but I don't remember the pitch, sorry!

Don't reinvent the wheel by machining the fittings, it's silly to
waste $100 to $200 of your time on a $5 part - you only do that when
it's made out of pure Unobtanium... Go to any refrigeration supply
house or search online.

They have in-stock adapters to go from NPT pipe thread to 1/4" SAE
Flare (HVAC and Refrigeration charging hose fittings) 3/8" SAE Flare
(manifold to vacuum pump hose connection) and 1/2" Acme Flare (R-134a
Automotive Manifold hose fittings)

Your vacuum pump should have 1/4" SAE Flare and 3/8" SAE Flare
fittings if it was made for refrigeration work - you connect the
manifold hose with the 3/8 fitting, and can attach the micron vacuum
gauge to the 1/4" to monitor your progress.

(If the system under vacuum has an extra service port, connect the
vacuum gauge sensor directly to it. That way you can isolate the
system with a ball valve and shut off the vacuum pump, and monitor the
vacuum levels for leaks and/or trapped moisture still evaporating from
the refrigeration oil.

If you are adapting an industrial vacuum pump, you'll have to
bushing down from 3/4" NPT down to the threads needed for the adapter.

-- Bruce --

[Richard J Kinch]

gary writes:

I plan on machining an adapter to get the 2 fittings connected
to each other.

Beware you don't commit an EPA felony. Such adapters are not government
approved.

[Bruce L. Bergman[_2_]]

On Sun, 14 Jun 2009 23:59:03 -0500, Richard J Kinch
wrote:

gary writes:

I plan on machining an adapter to get the 2 fittings connected
to each other.

Beware you don't commit an EPA felony. Such adapters are not government
approved.

What the (heck) are you talking about? They don't have to be
"government approved".

Unless they've made some serious changes since I took and passed the
test, there are no approvals processes or "lists of approved
machinery..." You just have to use procedures to reduce accidental or
incidental release of CFC's and HCFC's as much as possible. And
deliberate release is instant trouble.

A car using R-134a is running an HFC. No chlorine.

-- Bruce --

[Richard J Kinch]

Bruce L. Bergman writes:

They don't have to be "government approved".

The EPA via the Clean Air Act regulates what fittings can be used with what
refrigerants. Not the marketplace, not engineering standards, not the
convenience or expedience of you or me or the OP. I don't agree with the
despotism of the government, I'm just warning you. The law makes us all
criminals, even for things like cutting metal. The tender mercies of the
bureaucrats decide who is punished and who is given lenience.

[Bruce L. Bergman[_2_]]

On Tue, 16 Jun 2009 02:40:58 -0500, Richard J Kinch
wrote:

Bruce L. Bergman writes:

They don't have to be "government approved".

The EPA via the Clean Air Act regulates what fittings can be used with what
refrigerants. Not the marketplace, not engineering standards, not the
convenience or expedience of you or me or the OP. I don't agree with the
despotism of the government, I'm just warning you. The law makes us all
criminals, even for things like cutting metal. The tender mercies of the
bureaucrats decide who is punished and who is given lenience.

The service fittings permanently installed on the vehicle or
stationary system, yes. If you do a conversion from R12 to R134a or
another refrigerant you have to change the fittings to the proper
style to avoid accidentally mixing refrigerants.

But not an adapter made so you can hook up your service manifold
hoses to the car or refrigerator being serviced, or hook up the hose
from your vacuum pump to your service manifold. They may be stupid
MF's working for the government, but they ain't THAT stupid.

It's the mouth breathing politicians who wrote the impossible to
follow laws the bureaucrats are trying to (selectively) enforce who
*are* that stupid. Which is why politicians are like diapers - they
need to be changed often, and for the same reasons.

-- Bruce --

[Richard J Kinch]

Bruce L. Bergman writes:

But not an adapter ...

The EPA holds that if certain fittings are required, then adapters to
circumvent them are not permitted, since that defeats the very purpose of
the fittings, namely to make impossible the mixing or confusing of
refrigerants. While the utility of adapters is obvious, you're supposed to
have a separate set of gages and hoses for each refrigerant. That's the
governmental logic: intelligent economizing must give way to backstopping
presumed stupidity.

As Uncle Al sez, environmentalism is expensive, shoddy, and deadly.

[Steve W.[_2_]]

Bruce L. Bergman wrote:
On Tue, 16 Jun 2009 02:40:58 -0500, Richard J Kinch
wrote:

Bruce L. Bergman writes:

They don't have to be "government approved".
The EPA via the Clean Air Act regulates what fittings can be used with what
refrigerants. Not the marketplace, not engineering standards, not the
convenience or expedience of you or me or the OP. I don't agree with the
despotism of the government, I'm just warning you. The law makes us all
criminals, even for things like cutting metal. The tender mercies of the
bureaucrats decide who is punished and who is given lenience.

The service fittings permanently installed on the vehicle or
stationary system, yes. If you do a conversion from R12 to R134a or
another refrigerant you have to change the fittings to the proper
style to avoid accidentally mixing refrigerants.

But not an adapter made so you can hook up your service manifold
hoses to the car or refrigerator being serviced, or hook up the hose
from your vacuum pump to your service manifold. They may be stupid
MF's working for the government, but they ain't THAT stupid.

Want to bet!


It's the mouth breathing politicians who wrote the impossible to
follow laws the bureaucrats are trying to (selectively) enforce who
*are* that stupid. Which is why politicians are like diapers - they
need to be changed often, and for the same reasons.

-- Bruce --

True, It is a shame that the Constitution was written by folks who felt
that serving in government was such a PIA that nobody would WANT to do
it. Term limits were not considered because of that.

I'd like to see term limits for ALL elected offices. Never going to
happen though.



--
Steve W.

[RB[_2_]]

Steve W. wrote:
Bruce L. Bergman wrote:
On Tue, 16 Jun 2009 02:40:58 -0500, Richard J Kinch
wrote:

Bruce L. Bergman writes:

They don't have to be "government approved".
The EPA via the Clean Air Act regulates what fittings can be used with what
refrigerants. Not the marketplace, not engineering standards, not the
convenience or expedience of you or me or the OP. I don't agree with the
despotism of the government, I'm just warning you. The law makes us all
criminals, even for things like cutting metal. The tender mercies of the
bureaucrats decide who is punished and who is given lenience.
The service fittings permanently installed on the vehicle or
stationary system, yes. If you do a conversion from R12 to R134a or
another refrigerant you have to change the fittings to the proper
style to avoid accidentally mixing refrigerants.

But not an adapter made so you can hook up your service manifold
hoses to the car or refrigerator being serviced, or hook up the hose
from your vacuum pump to your service manifold. They may be stupid
MF's working for the government, but they ain't THAT stupid.

Want to bet!

It's the mouth breathing politicians who wrote the impossible to
follow laws the bureaucrats are trying to (selectively) enforce who
*are* that stupid. Which is why politicians are like diapers - they
need to be changed often, and for the same reasons.

-- Bruce --

True, It is a shame that the Constitution was written by folks who felt
that serving in government was such a PIA that nobody would WANT to do
it. Term limits were not considered because of that.

The founders all had things to do, like managing a business.
Government duties detracted from that.

I sure wish the people in Washington DC had other things to do.
Idle hands truly are the devils workshop

[Michael A. Terrell]

RB wrote:

The founders all had things to do, like managing a business.
Government duties detracted from that.

I sure wish the people in Washington DC had other things to do.
Idle hands truly are the devils workshop


Even the Devil has standards.


--
You can't have a sense of humor, if you have no sense!

[RB[_2_]]

Michael A. Terrell wrote:
RB wrote:
The founders all had things to do, like managing a business.
Government duties detracted from that.

I sure wish the people in Washington DC had other things to do.
Idle hands truly are the devils workshop


Even the Devil has standards.

Like the old joke about the testing lab that is switching from rats to
lawyers:

1 - Lawyers are more numerous
2 - Nobody cares what you do to a lawyer
3 - There are some things even a rat won't do

[Michael A. Terrell]

RB wrote:

Michael A. Terrell wrote:
RB wrote:
The founders all had things to do, like managing a business.
Government duties detracted from that.

I sure wish the people in Washington DC had other things to do.
Idle hands truly are the devils workshop


Even the Devil has standards.

Like the old joke about the testing lab that is switching from rats to
lawyers:

1 - Lawyers are more numerous

They multiply exponentially.

2 - Nobody cares what you do to a lawyer

Except another lawyer, but they don't matter.

3 - There are some things even a rat won't do

Not when there are so many out of work law students who weren't smart
enough to bribe their way past the bar.



--
You can't have a sense of humor, if you have no sense!

[[email protected]]

On Wednesday, June 17, 2009 at 3:16:09 AM UTC-4, Richard J Kinch wrote:
Bruce L. Bergman writes:

But not an adapter ...

The EPA holds that if certain fittings are required, then adapters to
circumvent them are not permitted, since that defeats the very purpose of
the fittings, namely to make impossible the mixing or confusing of
refrigerants. While the utility of adapters is obvious, you're supposed to
have a separate set of gages and hoses for each refrigerant. That's the
governmental logic: intelligent economizing must give way to backstopping
presumed stupidity.

As Uncle Al sez, environmentalism is expensive, shoddy, and deadly.

So ..leave those fittings for R134a on your hoses because they are not adaptors, but a permanent conversion to make an obsolete tool usable. If it became necessary to permanently convert the tool to R12, do so at that time.

[Doug Miller[_4_]]

wrote in news:a7fd83ff-db9e-4978-af08-7d8e10f86a79
@googlegroups.com:

On Wednesday, June 17, 2009 at 3:16:09 AM UTC-4, Richard J Kinch wrote:

So.... why are you responding to a SEVEN YEAR OLD post?

[[email protected]]

Well we noticed this really old thread and see that it still gets lots of hits on Google. So if anyone is still looking...

Gary: "But I can't figure out what the thread size is on the R134a. Please
enlighten me!"

I grabbed a bolt and checked if it screws in to the R134a in or out. It fits.

1/4" - 24

Meaning a 1/4" diameter bolt with 24 threads per inch (fine thread)

Someone should confirm this.... but does that help anyone?

[Ted[_31_]]

On Friday, December 22, 2017 at 6:03:17 AM UTC-8, wrote:
Well we noticed this really old thread and see that it still gets lots of hits on Google. So if anyone is still looking...

Gary: "But I can't figure out what the thread size is on the R134a. Please
enlighten me!"

I grabbed a bolt and checked if it screws in to the R134a in or out. It fits.

1/4" - 24

Meaning a 1/4" diameter bolt with 24 threads per inch (fine thread)

Someone should confirm this.... but does that help anyone?

thank you for posting the actual answer!
I can't believe I had to read through 8 years of useless rants to find the answer. thanks again.

[fyiman]

replying to melkie.au, fyiman wrote:
I don't have an R134a fitting handy so I can't check it, but ...

The "normal" thread pitch for a standard 1/4" bolt is 20 threads per inch
(TPI).
The "normal" thread pitch for a */fine/* 1/4" bolt is 28 TPI, not 24.

So, if it was a fine-thread 1/4" bolt, it's 28 TPI. Otherwise, if not, perhaps
you could check it with a thread guage.



--
for full context, visit https://www.polytechforum.com/metalw...ze-185313-.htm