CR3242-4-3 - Cherry Aerospace Oversized Blind Cherrymax Rivet

CR3242-4-3 – CherryMAX® Blind Flush Rivet (Oversize)

Part Number: CR3242-4-3 (also referenced as CR3242-4-03)

Manufacturer: Cherry Aerospace (A PCC Company)

Military Specification: NAS1097 / MIL-R-7885

Overview Section

The CR3242-4-3 is a high-strength oversize structural blind rivet featuring a 100° flush (countersunk) head. It is part of the world-renowned CherryMAX® family, recognized as the industry standard for high-reliability blind fastening in aerospace maintenance and manufacturing.

The "42" designation signifies the oversize diameter (1/64" larger than nominal), engineered specifically for MRO (Maintenance, Repair, and Overhaul) applications. It is the designated solution for restoring structural integrity when a standard 1/8" rivet hole has been enlarged, damaged, or cleaned of corrosion during the removal of an old fastener. By using the CR3242-4-3, technicians can achieve a precision interference fit in a reworked hole, maintaining the aerodynamic profile and structural load-bearing capacity of the airframe.

Enhanced Technical Data

Advanced Engineering & Structural Application

The CR3242-4-3 is designed for Structural Load Path Restoration. In aerospace structures, a loose or "smoking" rivet compromises the aircraft's fatigue life. The oversize shank of the -42 series fills the void created by hole wear, preventing "shuttling" (micro-movements) of the fastener.

Engineering Insight: The Bulbed Blind Head

During installation, the sleeve "bulbs" against the blind side of the structure. This creates a large, uniform bearing surface that distributes the clamping force over a wider area. This is particularly advantageous when fastening thin skins to heavier internal frames, as it prevents the rivet from pulling through the skin under high tensile loads.

Mechanical Safe-Locking Spindle

The hallmark of the CherryMAX system is the Integral Driving Anvil and Locking Collar.3 As the tool reaches the final pull stage, it drives the collar into the stem's locking groove. This ensures the stem is permanently retained, contributing its high-shear steel strength to the overall joint, unlike "pop" rivets where the mandrel is lost or non-structural.

Aircraft Compatibility

The CR3242-4-3 is ubiquitous in the Structural Repair Manuals (SRM) of virtually all metallic aircraft:

• Textron Aviation: Essential for Cessna Citation and King Air skin-to-rib repairs.

• Bombardier: Extensively used in the CRJ and Challenger series secondary structures.

• Gulfstream: Found in cabin pressurized bulkheads and floor structures.

• General Aviation: The "gold standard" for repairing loose 1/8" rivets on Piper, Beechcraft, and Mooney airframes.

The Cherry Aerospace CR3242-4-3 provides a critical engineering solution for airframe technicians. When a standard 1/8" rivet hole becomes oversized due to vibration or repair work, the CR3242-4-3 restores the original structural integrity of the joint. With a grip range specifically suited for material thicknesses between 1/8" and 3/16", this fastener combines the aerodynamic superiority of a NAS1097 flush head with the shear-load capacity of an 8740 alloy steel stem. The CherryMAX "Safe-Lock" system ensures that the stem stays put, providing peace of mind for pressurized cabins and high-stress airframe components.6

Installation & Maintenance Addendum

1. Hole Size Warning: Do not attempt to install this rivet in a standard #30 hole. It must be prepared with a #27 drill bit.

2. Tool Compatibility: Compatible with standard power and manual pulling tools, including the Cherry G704B, G747, and the G29 hand riveter. Ensure the pulling head is a dedicated CherryMAX type (e.g., H701-456).

3. Visual Confirmation: A correctly installed CR3242-4-3 will show the gold locking collar seated flush within the rivet head. If the stem breaks off below the head surface and the collar is missing, the rivet has not locked and must be replaced.

FAA PMA Alternate Part Number: Textron Aerospace Fasteners P/N - CR3242-4-3 [Click Here]

Product Overview

An item consisting of two or more of the following components: stem, rivet body, sleeve, expander, bolt, and collar. It is a headed fastening device with the shank designed to be expanded by means of a separate or integral stem or mandrel, or bolt and expander. It is designed to be installed or expanded from one side only. Excludes nut, blind assembly.

Specification:

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