The ARP Manufacturing process
Raw Material
In order to ensure optimum quality control, ARP has grown to be exceptionally self-reliant and now controls all aspects of the manufacturing process. All operations are performed in-house and closely monitored. This is how ARP has been able to establish a reputation for “zero defects” quality throughout the industry.
The process begins right at the mill, where ARP orders only premium grade materials including several proprietary alloys. The ever-popular 8740 chrome moly steel, for example, comes from the mill in four distinct grades. The lowest is “commercial,” which is followed by “aircraft quality.” ARP uses only the top two grades (SDF and CHQ), which cost twice as much, but provide the foundation for defect-free fasteners. These materials come in bar stock (for studs) and huge coils (for bolts).
Heading: cold or hot
Transforming raw material into a fastener begins with “hot” and “cold” heading processes. Material is fed into powerful devices and cold forged, or induction-heated and formed under tons of pressure.
Heat Treat & Shot Peening
Following the basic shaping, material is heat-treated to desired levels. This crucial process is done entirely in-house to assure total quality control. ARP uses special vertical racks to hold each piece individually and assure complete 360° penetration. This is far superior to commonly-used methods of dumping items into a large bin and batch-treating.
Fasteners are shot-peened after heat-treatment to remove any surface irregularities and improve overall external integrity.
Centerless Grinding
The Grinding Department is where all studs are centerless ground to ensure that they are perfectly concentric. As many as ten machining steps are required to achieve this level of accuracy.
Thread Rolling
The thread rolling operation (to MIL-S-8879A specs) is done after heat-treat, which accounts for a fatigue strength up to ten times higher than fasteners which are threaded prior to heat-treat.
Nut Forging & Tapping
ARP manufactures nuts in a multi-step process that begins with raw material being fed into a giant forming device that “blanks” the hex and 12-point nuts and continues with highly sophisticated automated threading equipment tapping each nut with an accuracy of .001˝ (which is five times higher than the aerospace standard). This ensures an exceptionally close-tolerance fit between the bolt/stud and nut.
A series of CNC-threading machines are employed by ARP to accurately tap the threads in nuts. Tolerances held are 5 times better than aerospace standards.
Metal Finishing
Metal finishing is also performed in-house at ARP. Operations include black oxide coating of chrome moly or polishing stainless steel to a brilliant luster.
R&D and Quality Control
A series of special checking devices are employed to monitor the quality of threads. For every thread size, there is a checking device.
A series of special checking devices are employed to monitor the quality of threads. For every thread size, there is a checking device.
Pack and Ship
Components for each kit are placed on the appropriate display cards, sealed and labeled.
