CR3242-4-4 – CherryMAX® Blind Flush Rivet (Oversize)
Available now through the AirParts Aero marketplace.
Overview Section
The Cherry Aerospace CR3242-4-4 (often listed as CR3242-4-04) is a high-performance 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-strength, structural repairs where access to the back side of the structure is limited.
This specific CR3242 series is the Oversize counterpart to the nominal CR3212.3 In aviation maintenance, when an original 1/8" rivet is removed, the hole often becomes slightly enlarged or irregular. The oversize 0.140" diameter (1/64" larger than nominal) is engineered to fill these expanded holes perfectly, providing a tight, structural interference fit without requiring you to move up to a 5/32" fastener.
Key Features Section
Locked Spindle Reliability: Features a visible, mechanically locked spindle (stem) that cannot vibrate loose, ensuring joint integrity in high-vibration airframe areas.
Bulbed Blind Head: During installation, the sleeve forms a large "bulb" on the blind side, providing an expansive bearing surface that prevents pull-through in thin sheets or composite materials.
Visibly Inspectable: The gold-colored locking collar is visible from the manufactured head side after installation, allowing for immediate quality verification.
One-Tool Versatility: CherryMAX rivets are designed with an integral driving anvil, meaning a single pulling head can install multiple diameters and materials without tool changes.
Flush Stem Fracture: The stem breaks off clean and flush with the head, eliminating the need for secondary trimming or shaving for aerodynamic smoothness.
Corrosion Resistance: The 5056 aluminum sleeve is chemically filmed per MIL-C-5541, offering excellent protection and compatibility with aluminum airframes.
Technical Specifications Section
| Specification | Detail |
| Part Number | CR3242-4-4 (CR3242-4-04) |
| Manufacturer | Cherry Aerospace |
| Head Style | 100° Flush Head (Countersunk) |
| Diameter | 1/8" Oversize (Actual: 0.140 in) |
| Grip Range | 0.188 in – 0.250 in (Size -04) |
| Sleeve Material | 5056 Aluminum Alloy |
| Stem Material | 8740 Alloy Steel (Cadmium Plated) |
| Hole Size Required | #27 Drill Bit (0.143 – 0.146 in) |
| Shear Strength | Approx. 530 lbs |
Aircraft Compatibility Section
The CR3242-4-4 is a staple for structural repairs across nearly all metallic aircraft:
Textron Aviation (Cessna/Beechcraft): Standard replacement for structural skin and rib repairs on models like the Cessna 172, 182, and King Air.
Piper Aircraft: Utilized for field repairs on the PA-28 Cherokee and PA-32 Saratoga series.
Bombardier / Learjet: Used in cabin furnishings and secondary structures.
Experimental (RV-series): The preferred oversize rivet for builders needing to fix a "missed" or enlarged hole in a 1/8" solid rivet line.
Technical Applications & Safety
The -04 grip length is specifically designed for a material thickness stack-up between 0.188" and 0.250".9
Safety Warning: Do not use a standard #30 drill bit. Because this is an Oversize rivet, a standard #30 (0.128") hole is too small. You must use a #27 drill bit (0.144") to ensure the 0.140" shank can seat properly. If the hole is too tight, the sleeve may buckle prematurely, or the locking collar may not seat, compromising the structural strength of the repair. Always verify the grip length with a grip gauge before installation; a rivet that is too short will not form a proper bulb, while one that is too long will leave a "loose" joint.
Technical Engineering Insight
The engineering value of the CR3242-4-4 lies in its Mechanical Joint Efficiency. Unlike standard "pop" rivets, the 8740 alloy steel stem remains locked inside the aluminum sleeve, essentially acting as a solid pin. This provides shear values comparable to solid AD-series rivets. The Oversize shank is critical for maintenance because it compensates for "hole wall deformation" caused by the vibration of the previous fastener. By using a slightly larger diameter, you restore the bearing area of the hole, preventing future "smoking rivets" and structural fatigue.
Installation & Maintenance Addendum
Tooling: Use a Cherry G704B or G747 power puller for optimum results. While hand tools like the Cherry G29 can work, the steel stem requires significant force compared to aluminum-stem variants.
Driving Anvil Identification: Oversize CherryMAX rivets are typically identified by a silver-colored driving anvil (the small washer on the stem), whereas nominal rivets feature a gold-colored anvil.11
Head Marking: The head is marked with a "4" to indicate the -4 diameter series and the manufacturer's symbol for easy post-installation auditing.