Process operations
The Pittsburgh Plug process
Coiled wire is the principal raw material ingredient, with sizes ranging up to over 1-1/16
inches in diameter. Various grades of steel, brass, and aluminum are purchased to exacting
specifications, free from non-metallic inclusions, segregations, and seams. Essentially a
scrapless operation, with no cut-off or trimming waste, all plug blanks are held to
extremely close tolerances to assure leak-proof seals after threading.
01
Cold Forming
Cold forming is the first step in the processing of our precision-fit plugs.
This method was developed in Germany, prior to the close of World War II, and designed to
form metal at high production rates into finished net shapes with no material waste.
Pittsburgh Plug uses National five-die cold formers with capabilities ranging from 85
through 300 tons.
Engineering concepts of proven success through years of production include:
- Power feeding
- Rugged bushing-type cutters
- Rotating and non-rotating transfer
- Finger spreading
- Re-circulating lubrication
- Practical, efficient expendable tooling manufactured in-house
02
Precision Threading
Quality pipe threads must be perfectly round, fully formed and uniformly tapered. To
secure the outmost repeatability, Pittsburgh Plug utilizes Reed tri-roll cylindrical die
machines, equipment that provides infinite control of die speed, blank revolution, and
blank penetration rate.
The three dies, which are circular in shape, cam in on the work piece (or plug blank),
while rotating at a predetermined rate of speed. The diameter of the finished thread is
controlled by the diameter of the work piece. Threads generated are strong, highly
burnished, and precisely tapered.
03
Thread Coating
The assurance of perfect sealing is another vital feature in the quality of our plugs.
Pittsburgh Plug has custom built process lines for applying external thread coatings,
including pre-applied thread sealant, to both ferrous and non-ferrous plugs, with
automated fixturing, convection drying and on line packaging.
In process fiber optic and laser inspection devices provide production integrity, virtual
assuring defect free products. Coating materials are supplied by Loctite™,
3M™ and N-D Industries™.
04
Secondary Operations
Secondary operations are performed on special purpose automatic machines that compliment
fast and efficient production methods, allowing a finished plug to leave the plant ready
for assembly.
- Secondary machining
- O-ring installation
- Magnet installation
- Chucking and roll threading
