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This section provides an overview for r screws as well as their applications and principles. Also, please take a look at the list of 4 r screw manufacturers and their company rankings. Here are the top-ranked r screw companies as of January, 2025: 1.Sanko Techno Co. Ltd., 2.West Coast Lockwashers, Inc.
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1985-2014: Worked for Alstom Corporation, ABB Corporation, and Gadelius Corporation, designing Jungstrom air preheaters and mechanical design of diamond soot blowers. (ABB Corporation: https://new.abb.com/jp)
2014-2021: Worked as an engineering and project manager at Alvos Inc.
https://www.linkedin.com/in/yoichi-hiroki-92192394/
R-Threads are a common name for tapered pipe threads.
The term "R-Threads" is so called because the male threads of R-Threads are called "R" and the female threads are called "Rc" in the JIS and ISO standards.
R Screws are used in "threaded pipe fittings" and "pipe end threads," and are used for pipe joints.
Figure 1. Example of piping use of R screw (tapered pipe screw)
R Screws (tapered pipe threads) provide excellent airtightness at joints in piping installation, with minimal leakage of fluid in the pipe. For this reason, R-Threads are used in joints of various types of fluid transport piping, pneumatic equipment, vacuum equipment, and other piping where fluid leakage is a fundamental problem.
The principle of the R Screw is explained here using the typical "JIS B0203 Tapered pipe threads. The standard profile of a tapered thread is a 1:16 taper to the center axis of the pipe or fitting thread.
Parallel female threads are threaded parallel to the center axis. See Figure 2 for reference profiles of tapered and parallel threads.
Figure 2. Taper external screw for pipes, internal screw, and parallel internal screw
In the R Screw, the outer diameter on the male thread side increases as one moves away from the tip, and the inner diameter on the female thread side decreases as one moves away from the end. Therefore, the deeper the threading depth, the more closely the male and female threads adhere to each other, resulting in a mechanism that increases airtightness.
As with pipes, pipe taper threads are generally nominated in inches, with 1/8-inch (for 1/8B or 6A pipes) threads called "itibu" and 1/4-inch (for 1/4B or 8A pipes) threads called "nibu". As mentioned above, in addition to the R Screw, there are various other standards for pipe threads, such as Rp (parallel pipe threads for tapered pipe threads), G (parallel pipe threads), and NPT (tapered pipe threads for general use in the United States).
Since screws of different standards cannot be connected, it is important to select the appropriate standard screw according to the specifications of the equipment and joint to be used.
Typical examples of products using R Screws are as follows.
Refer to Figure 3 for pipe fittings using R Screws and male threads at the pipe ends.
Figure 3. Pipe fittings using R screw, external screw at pipe ends
Since R Screws are threaded joints, they are much easier to install than welded or flanged joints.
The standards for R Screws and Taper Pipe Threads are as follows
In JIS B0203, the notation of R Screw is as follows.
*Including some distributors, etc.
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DAI-ICHI Sokuhan Works Co, founded in 1944 is based in Ojiya, Japan, and is a manufacturer and supplier of machinery tool accessories. Their product portfolio includes measuring instruments, air micrometers, electronic micrometers, gauges, precision machine parts, spindle units, and kneading dispersibility measurement. The products are manufactured under superior technology and precision with quality control. The products are used in multiple industries which include aircraft, trains, automobiles, and other modes of transportation.
Häfele SE & Co. KG, established in 1996 and headquartered in Montreal, QC, Canada, is a manufacturer and supplier of machining and fabrication equipment. The company is an experienced specialist for intelligent hardware and fitting systems, lighting, and electronic access control systems. Its product range of over 150,000 items includes home and commercial building furniture and interior finishings, such as doors, handles, and fittings. The company serves various customer segments, including commercial building developers, distributors, and individual consumers.
West Coast Lockwashers, Inc. is a well-established manufacturer of lockwashers and related hardware products. It is headquartered in Industry, California, and was established in 1957. The company specializes in the distribution of lock washers, flat washers, spring washers, threaded fasteners, and plastic components. It also offers many plastic components, such as bushings, grommets, and spacers. The company's customers include manufacturers, distributors, and government agencies. West Coast Lockwashers also offers custom manufacturing capabilities and responsive customer service.
Ranking as of January 2025
Derivation Method| Rank | Company | Click Share |
|---|---|---|
| 1 | Sanko Techno Co. Ltd. |
66.7%
|
| 2 | West Coast Lockwashers, Inc |
33.3%
|
Derivation Method
The ranking is calculated based on the click share within the r screw page as of January 2025. Click share is defined as the total number of clicks for all companies during the period divided by the number of clicks for each company.Number of Employees
Newly Established Company
Company with a History
*Including some distributors, etc.
| Country | Number of Companies | Share (%) |
|---|---|---|
|
Japan
|
2 | 66.7% |
|
Germany
|
1 | 33.3% |
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