A long, long, time ago there lived a designer of mechanical things who thought up this amazing new type of horse shoe. He brought his idea to the blacksmith who threw up his hammer and exclaimed, "I have great skills, but that can't be made!". So began the historic struggle between engineers and machinists.
That struggle continues today but I don't understand why. Yes, there are times as a machinist that I get prints with incomplete information or RFQ'S that are imposible to quote because the purchasing person doesn't know the answers but, for the most part, I have always gotten along with engineers.
I admit, I am prejudice. Even though I have never been a practicing design engineer, I do have my degree in that discipline. But that aside, I find that working directly with the engineers on a project is really efficient and usually turns out well for me and the machine shop. I get direct answers to direct questions, usually very quickly. I get the important information that I need to make parts right. And, I get their humor!
If I had a wish (after all, this is a fairy tale) it would be that engineers work with machinists, fabricators, and installers closer to the beginning of a project. Even more amazing things would be made!
Reducing weld necks are an elegant solution to a common problem. Something has a particular flanged outlet but you want a smaller size pipe attached to it. The problem is that, for most commercial flanges whose dimensions are described by ANSI B16.5, reducing weld necks are not addressed. Section 3.3 of B16.5 mentions reducing flanges and refers to Table 7 which explains about reducing threaded flanges but not weld necks. That doesn’t mean that you can’t make them. Here is how it works:
Now let’s look at the following tables from ANSI B16.5 to see what flange you would get. The outside diameter of the flange, O, the body thickness, Tr, raised face dimension, R (specified on Table 4 for all flanges), and bolt pattern will all be for a 4” 150# flange.
O = 9.000”
Tr = .88” + .062” for the raised face height = .940”
R = 6.190”
Drilling = 8 - .750” holes on a 7.500” Bolt Circle
Next we incorporate the 2” reducing hub to the 4” body. The hub diameter, X, the beginning diameter of the chamfer, Ah, and the bore size for a 2” schedule 40 pipe, B, are all taken from the 2” 150# line of the table:
X = 3.060”
Ah = 2.380”
B = 2.067”
The only dimension left to determine is the length through the hub, also called the over-all length or AOL. This is important because some engineer probably wants to make this assembly part of a larger system of a certain length. To do this we need to do a little math (oh, no!). We are going to figure out the height of the hub only for a 2” 150# weld neck and add it to the body thickness of the 4” flange. In our example the 2” weld neck has a length through hub of 2.440” and a body thickness of .690” which, when subtracted (hey, I warned you there was going to be math involved) gives us a hub height of 1.750”. Now let’s add that to the body thickness of the 4” 150# flange, Tr, from above of .940” to get the reducing hub length, Y, of 2.690”. That is a good bit shorter than the 3.000” of a standard 4” 150# weld neck.
Check out the shop print for our finished reducing flange. We hope that this helps you understand reducing weld necks a little better. Reducing slip-on and reducing threaded flanges are much simpler … but that is a topic for another time.
As a manufacturer, we understand that the true cost of material is not just in the price that you pay. Sometimes, raw steel may be cheaper but harder to machine making it more expensive in the long run. This applies to many other things as illustrated in this article:
Enjoy the read!
What exactly is a flange?
Let's face it. This is the era of the e-mail, text and other forms of digital communication. This has it's good points and bad and this is not where I want to get into that. What I want to talk about is the "copy and paste" function. We get a lot of inquiries by e-mail where a person had copied and pasted an item description from somewhere and sent it. Many times, there is missing information which we then ask for so that we can quote the correct part. Now, We always try to assume the best in everyone so we believe that, being in a hurry, the missing information is an over site and not because someone doesn't know what they are looking for. But, also being pragmatic, we wanted to take steps to make sure that everyone that we work with is well informed. To help, we added a page to our web site for downloads of useful items like piping bore charts, decimal equivalents, and more. Also, we have a series of videos in production that explain what a flange is, how and why they are used, how to describe them, and some of the machining details that are sometimes asked. We hope that you have as much fun watching the videos as we are having making them.
Without sounding too cocky, we know our business really, really well. For 50 years we have been making primarily forged pipe flanges. I can't even think about the different variations of just flanges that we have made during that time. Between the different nominal pipe size of the flange, the pressure class, the face type, the style of flange, the bore size, the dimensional specification, the material grade and the surface finishes available ... it has to be in the hundred of thousands.
Now, looking at all of those variations, it is hard for someone not in the manufacturing world to understand all of it. We realize now that in addition to making the correct product for our customers, what we really provide is our vast history and knowledge. We will be producing videos about pipe flanges to help train all of those people in the industrial pipe, valve and fitting business who would like to talk more intelligently to their end users about this product. Flanges themselves are not sexy but we will be making these short videos as fun as possible. Stay tuned!
Pretty much every manufacturer worth their salt is ISO 9001 certified. We have had a full quality assurance manual since the 1970's so, why ISO? Basically, we have been doing the "work" of being ISO compliant for many years. The Navy and commercial industries have always insisted on product traceability, product inspection and all of the documentation to correctly process orders and contracts.
Here's how I see it. It comes down to trust. ISO is recognized by our customers and others that if a company is certified by ISO then they can be trusted to do a good job and provide the correct products.
We have added to our existing QA Manual to include the areas of our operation, like marketing, quoting, sales, and accounting, that are not directly involved with producing the actual product but and, obviously, very important to providing great products to our customers. Piping Supplies Inc will be ISO compliant on January 1, 2017. After 1 year of running the program we will get our certificate.
I look forward to continuing this process. One of ISO 9001's more interesting aspects is the concept of continuous improvement and also risk taking. I like that. Give me your thoughts.