Metal Fittings Comparison for Computer Liquid Cooling applications
Including Straight barbs, Rotaries, Compressions, Adapters and Stop Plugs

November 16, 2008

In recent weeks, we have noticed something among the mass of metal in our stock room. What we have noticed is in spite of similar looks, shapes and sizes, not all fittings are created equal. Therefore we thought it might be helpful to consumers if we took some simple measurements of these various parts and made a helpful comparison chart. With this, we want to make some important points. First and foremost, this data is not meant to show a favored or ill-favored fitting, adapter, rotary, compression, etc. We believe that every fitting can have specific purposes and usefulness regardless of what can be viewed as a negative data entry. All measurements were taken using a standard 6" Venier Digital Caliper. For each data point, multiple measurements were taken in an attempt to find the "dead center" of, for instance, the maximum ID size of a straight barb. Because of the sometimes inconsistent nature of measuring circular and angled measurement points, as well as inconsistent plating processes, users viewing this data should allow for at least, and sometimes more than +/- 0.10 mm of tolerance. In cases of a surprisingly large or small measurement for fittings of a certain class, we took additional measurements to ensure what we were recording was as accurate as possible. These are real world, non scientific data. A sample of each fitting was taken at random from our active inventory to eliminate potential "cherry" measurements. Aside from typographical errors, requests from manufacturers or distributors to alter the below data will not be granted. All data contained on this page is Copyright 2008, Sidewinder Computer Systems Inc. Reproduction of all or part of this page without explicit, written authorization is prohibited. Users are welcome to submit any requests, ideas or other comments, or, if you have a new fitting you'd like to see added, please email us.. We'd like to expand this data to include other fittings, and this is a work in progress.

And now, some information on what each data point indicates.

ID = Inner Diameter
OD = Outer Diameter
Max Width - Where the fitting is the widest regardless of the location. For straight barbs, this is always the hexagonal grip area.
Max Height - Where the fitting is the tallest from bottom to top. This figure includes the threads.
Max Height When Installed - A measurement from where the threads end to the top of the fitting. This figure can be useful if your application requires a low profile fitting. The o-ring is removed for this measurement.  
Thread Type - Watercooling products today generally use BSPP, or G, threads. Other variants include NPT, NPSC, NPTR, NPSM, NPSL, NPTF, and BSPT.
Max ID Thread Side - This indicates the maximum inner diameter on the threaded side of the fitting. (the side you would install into a waterblock, etc.)
Maximum Barb ID - The maximum inner diameter of the barb. This is where your tubing is placed onto the fitting.  The measurement was taken immediately inside of the end of the barb.
Maximum Barb OD - To measure this figure, we used the long edge of a caliper and took the highest data point from the front of the barb to where the tubing would seat.
Minimum Barb OD - We felt this figure was useful to help determine the size of a fitting's lip, or the barbed part of the fitting. The measurement was taken immediately following the barb lip.
Max Lip Height - The maximum height of the most effective barb. Some fittings contain more than one barb, but the first is always the most important, as it is the tallest, and last "wall" of defense against potential leaks.
# of Barb Lips - The number of raised areas on the barb side of a fitting. The number indicated has to be an "effective" lip and not just something that we can feel with our fingernail. What we consider effective is if the height is at least 50% of the initial lip. In the case of the EK barbs, the 2nd and 3rd lips are right around 50% of the first lip's max height.
Weight - Accurate to within 5 grams. If a weight fluctuated within two numbers, we split the difference. 

Data Updated Nov 25, 2008
All Measurements are in Millimeters