CR3242-4-04 - Cherry Aerospace Flush Head Blind Oversize Cherrymax Rivet

CR3242-4-04 – CherryMAX® Blind Flush Rivet (Oversize)

Part Number: CR3242-4-04

Manufacturer: Cherry Aerospace (A PCC Company)

Military Specification: NAS1097 / MIL-R-7885

Overview Section

The CR3242-4-04 is a high-performance oversize structural blind rivet featuring a 100° flush (countersunk) head. It belongs to the industry-standard CherryMAX® family, specifically engineered for airframe maintenance and repair. The "42" designation indicates this is the oversize variant, designed to provide a precision interference fit in rivet holes that have become slightly enlarged, worn, or "out-of-round" during the removal of previous fasteners.

With a nominal diameter of 1/8" (+ 1/64" oversize), the CR3242-4-04 restores the structural integrity of the joint by ensuring total hole-fill. It features a mechanically locked spindle and a "bulbed" blind head, making it a certified, airworthy replacement for solid rivets in areas where access is limited to a single side.

Enhanced Technical Data

Advanced Engineering & Structural Application

The CR3242-4-04 is engineered for Structural Load Transfer. Unlike standard blind rivets, the CherryMAX system utilizes a heat-treated steel stem that stays locked within the aluminum sleeve, essentially providing the shear strength of a solid steel-core rivet.

Engineering Insight: The NAS1097 "Reduced Head" Advantage

The flush head on this rivet is designed to the NAS1097 standard. This "reduced head" profile allows the rivet to be installed in thinner exterior skins without the risk of "knife-edging" (where the countersink penetrates the entire thickness of the skin). This design preserves the fatigue life of the aluminum skin by maintaining a cylindrical bearing surface for the rivet shank.

The Safe-Locking Mechanism

As the installation tool cycles, a gold-colored Locking Collar is driven into a precision-machined groove in the stem. This mechanical lock prevents the stem from vibrating loose, which is critical in high-vibration areas near engines or flight control surfaces.

Aircraft Compatibility

The CR3242-4-04 is a critical part in the Structural Repair Manuals (SRM) of the following:

• Textron Aviation: Cessna Citation and Beechcraft King Air series skin repairs.

• Bombardier: Challenger and CRJ series secondary structural assemblies.

• Piper & Beechcraft: Standard for wing and fuselage skin maintenance on pressurized and non-pressurized models.

• MRO Standard: The "go-to" fastener for repairing standard 1/8" rivet holes that have been drilled out to clear corrosion.

The Cherry Aerospace CR3242-4-04 is the industry’s solution for restoring structural airframe integrity when original rivet holes are no longer within nominal tolerances. By moving to the oversize "42" series, technicians can clean up damaged holes using a #27 drill and achieve a perfect interference fit. This fastener combines the aerodynamic benefits of a 100° flush head with the immense shear strength of an 8740 steel stem. When your repair demands an exact grip range of 0.188" to 0.250" and uncompromising safety, the CR3242-4-04 provides a permanent, mechanically locked result that meets the highest FAA and EASA standards.x

Installation & Maintenance Addendum

1. Hole Precision: This rivet must be installed in a hole prepared with a #27 drill bit. If the hole is too small, the sleeve will be damaged during insertion; if too large, the bulbed head will not properly seat against the back-side structure.

2. Grip Range Verification: Always use a Grip Gauge to ensure the material stack-up is within the specified range. For the -04 grip, the total thickness should be between 3/16" and 1/4".

3. Tooling: Use a specialized CherryMAX pulling head (such as the H701-456 or H747-456) to ensure the locking collar is correctly sheared and seated.