This is for a new installation, big sink commercial sink for cleaning brewing mess in my garage which in theory keeps my wife happy about less scattered mess in the house and yard.
I have a backsplash mounted commercial faucet (Royal 303W) with what I am 99.8% certain are 1/2" female NPT threads.
I asked at the local plumbing supply parts house what I needed and they gave me what was labeled (on receipt, not sure about brand in reality) as a Fischer faucet installation kit which is very similar to 1/2" NPS / BSP... you get what I'm talking about - parallel threads which are slightly smaller in diameter than NPT threads.
Using PTFE tape I threaded it into the back of the faucet using a piece of leather to protect the threads and a vice-grip to tighten and have it mounted to the backsplash with the included locknut and washer. Seems good, but is this the correct method of mounting the part?
I looked on the wall and found a nipple with tapered threads on one end and parallel threads which seem closer to the correct part - even though tapered on both ends with parallel threads in the middle for the NPSL (excuse my use of old McMaster terminology) would have seemed like the ideal choice. Essentially, one end of either product will be threaded into something with slightly incompatible threads. I'm going to a barstock street elbow on the back so the sink can be mounted up against the wall. That part was labeled online as 1/2 NPT (will see when it arrives).

On a side note, I tee'd off the cold water supply line to run through a filter, and am planning on running it to the backsplash for filtered water. To save time and money using parts I already have on hand I was going to use a stainless gate valve. How good / bad of an idea it is to be using a stainless valve for clean brewing water considering galvanic corrosion between the brass and stainless? Not just the cleanliness of the water, but in the long term I don't want the parts to corrode together and make it someone else's headache when I get too old to make beer. There must be some reason why I've never found SS fittings in plumbing supply stores. I was considering using a T&S Brass B-0425 supply nipple to attach the valve and call it a faucet. Street elbow and cam-lock fitting to get the filtered water to a brewing kettle. Scrap 316 SS tube is traded for beer by the owner of a company which bends tube for the semiconductor industry. It is practically free to me, but SS compression fittings are another story. The rest of the supply side is plumbed using PEX.
Cheers

There is no problem with stainless steel to brass, but I think you are making your faucet connect WAY TOO DIFFICULT. Just use a close nipple into an elbow, with a washer to compensate for the thinness of the sink back.

tapered or parallel?

A close NPT (tapered) nipple will not protrude through the thin backsplash with more than two threads exposed using the Royal faucet mentioned. The person that sold me the faucet said to use a close nipple as well. Didn't state tapered or parallel, but just about every close nipple out there is tapered.
I wanted to get a piece of scrap 18 gauge stainless sheet about 12" x 4" to reinforce behind where the faucets mount to the backsplash, essentially making it stronger and distributing the area of stress put on the sink's thin walls. If I were to do that, only one thread would be exposed using a NPT close nipple.
Forget the rest for now, will the Fisher 64238 work without leaks between it and the Royal faucet? Again, compatibility between the different variations on tapered threads and parallel threads? I've made the connection without leaks in the past but not under city water pressure.



Edited 1 times.

then get a 'short' nipple or a 'shoulder' nipple or whatever length you need

close = no 'gap' between threads on end

short = small gap between threads on ends

shoulder = 1/2" gap


ps. a plumber would have 'runs' of nipples on the truck AND a folding rule with the knowledge required

(or used to, once upon a time, in a land far far ago)

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

I appreciate the fact that a plumber would have the parts and knowledge. When paid cash for a quote to install a laundry sink and tie it in to the existing wet vent the first quote was for $1800 with me providing the sink and faucet, no replacement of drywall or cleaning up included in the estimate. When I called back for an explanation, as in a breakdown into hours and rate of labor, estimated parts I was told the message would be passed along.
I never got a call back. They took my cash and wrote something too absurd for me to agree to and the plumber had lunch money. End of story with that company which paid for google advertising.
Then I got a lowball offer from someone pretending to be a plumber. Said he was licensed but I didn't ask for the license number or references. After it was clear he knew absolutely nothing, caught him stealing from Lowes, then he almost cut through my water supply line with a sawz-all I returned with a .357 on my hip, under my shirt but imprinting, and paid him $60 to leave, NOW. He went to the gas line section when looking for water fittings.
There are bad examples of pro's and scammers, I got both. Then was out over $100 between the two. $400 for a sink and partial faucet, $200 in parts bought for the crackhead with $100 in repair parts for damage repair and no beginning on the install, only cleanup. I'm now $1000 into the project and 7 days of my own work.

So you begrudge a professional for spending his time to write up your estimate, knowing that his knowledge and experience can get the job done correctly? Do you really think that his time and knowledge are worthless? Was the bid higher than you wanted? Obviously. Was it higher than it should have been for a professional in your area? No idea. A second bid from a licensed and insured company would have been prudent before hunting for any random person to do the job.

the threads in the faucet ARE tapered threads. If a close is too short, then use the next longest one. THe back of the sink is PLENTY strong to support the faucet, but if you use steel washers to compensate for the excess length of the nipple THAT will reinforce it.

Parallel threads to female tapered faucet, problem or not a problem?
Thanks for the reply by the previous plumber.

As to the reply before that one...
I'm not going to argue with you and believe you are correct in most aspects where I have been correct in some.
The estimate I received twice the "High" using online tools to see what the cost should be for this type of job performed by a licensed professional.
Yes I should have had a second and third estimate. It seems as I have had this forum turning up in search engines more and more it seems every post is by a licensed professional scolding someone when the banner across the top of the page says "Thank you plumbing pros for your advice & expertise", not "please post here to be laughed at". Just keep that in mind when people are looking for advice online, this forum is reflecting that attitude to the world.

Let me buy you a beer, I'm not your enemy and even if you were I would be civil about it.



So thank-you for your advice and expertise, enjoy your afternoon.



Edited 2 times.

quote; a folding rule with the knowledge required

(or used to, once upon a time, in a land far far ago)

When I was an apprentice, I bought the Lufkin rule with the 6" extension slide, but When I went to a jobsite to check on the journeymen, it seemed like someone always needed a ruler and I gave mine to him. I finally gave up and started carrying a tape measure because they did not know how to use that so I could keep it a little bit longer.

quote; using online tools to see what the cost should be for this type of job performed by a

And what were these "online tools", because only an @#$%& would even consider giving a VALID estimate for job he has not personally looked at? I hve been in the business overf 60 years, running companies for others and myself, and ANY estimate given over the phone is so loaded with caveats, (which amazingly the customer never seems to hear, they stop listening when they hear a price), that it is almost worthless.

hj;

mine had / has THIEF written under the slide

always got 'er back

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

BrewerJeff,

Just go to the plumbing supply or local hardware store and get a short and a shoulder nipple and a few fender washers to fit them. The washers will act as shims and reinforcers.

short will be 1.65 to 1.75" E-E

shoulder will be 2" E-E

the above measurements are for BOTH 1/2 & 3/4 IPS

you should have 1/2" makeup on both ends so subtracting 1" you will most likely actually need the 'short' nipple depending on the thickness of your sink and backing washer(s)

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

I was more interested in keeping them working so I just went and bought another one.

I was too frugal, er that would be cheap


(for the OP):


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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638