CR3242-4-02 – Cherry Aerospace OEM CherryMax® 1/64" Oversize Shank Repair Rivet
Available now on the Airparts.aero Marketplace.
Overview
The Cherry Aerospace CR3242-4-02 is a high-strength, 1/64" oversize shank, mechanically-locked blind rivet. This is not a standard production fastener; it is a flight-critical component engineered specifically for performing certified structural repairs on an airframe. Its primary purpose is to replace a nominal 1/8" diameter (dash-4) rivet that has been removed. When an existing rivet is drilled out, the hole is often left slightly enlarged or damaged. To restore the full structural integrity of the joint, the hole is reamed to the "first oversize" dimension, and this CR3242 oversize rivet is installed. Its shank is precisely manufactured to be 1/64" larger than a standard -4 rivet, ensuring a clean, interference fit that re-establishes the joint's original shear strength and fatigue life.
Like all CherryMax® products, the CR3242-4-02 features a mechanically locking spindle that is virtually immune to vibration, a large bulbed blind-side footprint for superior load distribution, and a 100° flush head for aerodynamically smooth surfaces. For any A&P/IA or structural technician performing a repair in a blind-access area, the CR3242 is the definitive, industry-standard solution for restoring the airworthiness of the structure.
Key Features
1/64" Oversize Shank: Specifically designed for structural repair applications to ensure a tight, interference fit in holes that have been reamed to the first oversize dimension.
Mechanically Locked Spindle: A separate Monel locking collar is swaged into the rivet head, creating a positive mechanical lock that prevents spindle loss due to vibration.
Bulbed Blind-Side Footprint: Forms a large, load-bearing bulb on the blind side, distributing loads over a wide area, which is ideal for thin-sheet and composite repairs.
100° Flush Head: The countersunk head design allows for a smooth, aerodynamically clean finish on external aircraft skins.
Engineered for Repair: The premier, certified solution for restoring the integrity of a joint after the removal of a nominal-sized fastener.
Technical Specifications
Part Number: CR3242-4-02
Component Type: Oversize Shank, Mechanically Locked, Bulbed Blind Rivet
OEM Manufacturer: Cherry Aerospace (a division of PCC Fasteners/SPS Technologies)
Head Style: 100° Countersunk Flush Head
Nominal Diameter: -4 (for 1/8" rivet callout)
Actual Shank Diameter: 0.140" - 0.141" (1/8" + 1/64" Oversize)
Maximum Grip Length: -02 (2/16" or 0.125 inches)
Grip Range: 0.094" to 0.125"
Material (Sleeve): 5056 Aluminum Alloy
Material (Spindle): Alloy Steel
Material (Locking Collar): Monel
Governing Specifications: Conforms to Procurement Specification NAS1398 for oversize rivets.
Aircraft Compatibility
Universal Repair Application: The CR3242 is a standard repair fastener used across the entire aerospace industry. It is specified in the Structural Repair Manuals (SRMs) for virtually all modern aircraft, including those from:
Boeing, Airbus, Textron Aviation (Cessna, Beechcraft), Lockheed Martin, Bombardier, Embraer, and others.
Note: The specific application of the CR3242-4-02 must be verified against the aircraft's Structural Repair Manual (SRM). The choice of fastener is a critical engineering decision.
Applications
Primary Structural Repair: The definitive fastener for blind repairs where an existing 1/8" nominal rivet hole has been drilled and reamed to the first oversize dimension to remove damage or corrosion.
Restoration of Joint Integrity: Used to restore the full shear and tensile strength of a compromised fastener hole in skins, ribs, spars, and stringers.
Why Choose CR3242-4-02?
An airworthy structural repair is not optional. Simply installing a nominal-sized rivet into a worn or damaged hole results in a loose, compromised joint that cannot properly transfer shear loads, leading to fretting, fatigue, and eventual failure. The CherryMax® CR3242-4-02 is the engineered solution to this problem. Its precisely oversized shank guarantees the restoration of a tight, interference fit. Combined with the proven reliability of the mechanically locked spindle and the large bearing footprint, this rivet ensures that a blind repair is as strong and reliable as the original production joint. For structural repair, there is no substitute for using the correct, specified oversize fastener.
The engineering principle that necessitates the use of the CR3242-4-02 oversize rivet is the restoration of bearing stress and joint stiffness. When a nominal rivet is removed, the hole is inevitably enlarged. Installing another nominal rivet would create a clearance fit, allowing for relative motion (slippage) between the fastener and the sheets under shear load. This slippage concentrates the entire load on a very small area of the hole's edge, causing extremely high bearing stresses that can lead to hole elongation and premature fatigue failure. By reaming the hole to a clean, uniform, first-oversize dimension and installing the precisely matched CR3242 shank, a proper interference fit is re-established. This ensures that the shear load is evenly distributed (borne) across the entire projected area of the rivet shank, returning the joint's bearing stress and overall stiffness to the original design values and restoring its full fatigue life.
Note: The CR3242-4-02 is a flight-critical repair fastener. It must be installed in a hole that has been precision-drilled and/or reamed to the correct first-oversize dimension as specified in the aircraft's Structural Repair Manual (SRM). It requires the use of the correct, calibrated Cherry Aerospace tooling, including the specified pulling head and riveter, for proper installation. Use by certified structural A&P/IA mechanics is required.
Documentation
Cherry Aerospace® Website: Comprehensive technical data, standards, and installation guides for the CherryMax® family of fasteners can be found on the official PCC Cherry Aerospace® website.
NAS1398: The procurement standard that defines the requirements for oversize shank blind rivets.