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Overview

Bulbed CherryMax

CherryMAX® is a locked spindle blind rivet with a visibly inspectable mechanical locking device and its own installation washer, which eliminates the problems resulting from worn tool anvils. It is called a "bulbed" fastener due to its large blind side bearing surface, developed during the installation process. CherryMAX® rivets are used in thin sheet applications and for use in materials that may be damaged by other types of blind rivets.

The CherryMAX® rivet is the most reliable, high strength structural fastener with visual inspectability in the world today.  It features the "Safe-lock" locking collar for more reliable joint integrity, and meets the requirements of PS-CMR-3000.

CherryMAX® tooling provides the simplest, most trouble-free installation tooling system. CherryMAX® fasteners are currently available in 1/8" through 1/4" diameters in both nominal and 1/64" oversize diameters. The tools use a single pulling head to install many diameters, head configurations, and material combinations.

Features

CherryMAX® Rivets consist of four components, assembled as a single unit:
  1. A fully-serrated stem with break notch, shear-ring and integral grip adjustment cone.
  2. A driving anvil to ensure a visible mechanical lock with each fastener installation.
  3. A separate, visible and inspectable locking collar that mechanically locks the stem to the rivet sleeve.
  4. A rivet sleeve with recess in the head to receive the locking collar

Installation


For an animation illustrating the installation process, please click here.

Stage 1

The CherryMAX® Rivet is inserted into the prepared hole, and the pulling head (installation tool) is slipped over the rivet’s stem. Applying a firm, steady pressure, which seats the rivet head, the installation tool is then actuated.

Stage 2

The pulling head holds the rivet sleeve in place as it begins to pull the rivet stem into the rivet sleeve. This pulling action causes the stem shear ring to upset the rivet sleeve and form the "bulbed" blind head. Formation of the rivet sleeve’s "bulbed" blind head is complete.


Stage 3

The continued pulling action of the installation tool causes the stem shear ring to shear from the main body of the stem as the stem continues to move through the rivet sleeve. This action allows the fastener to accommodate a minimum of 1/16" variation in structure thickness. The Locking Collar then contacts the Driving Anvil. As the stem continues to be pulled by the action of the installation tool, the "Safe-lock" Locking Collar deforms into the rivet sleeve head recess.

Stage 4

The "Safe-lock" Locking Collar fills the rivet sleeve head recess, locking the stem and rivet sleeve securely together. Continued pulling by the installation tool causes the stem to fracture at the break notch, providing a flush, burr-free, inspectable installation.

Benefits

Driving Anvil

A driving anvil is part of each CherryMAX® Rivet assembly. This Driving Anvil eliminates wear and replacement of expendable installation tool components, considerably extending the life of the installation tool.
It also allows a single pulling head to install:

  • 1/8", 5/32", and 3/16" Nominal and Oversize Diameter Rivets.
  • Protruding, 100° Flush and 100° Flush Shear, Unisink, and 120° Flush Head Styles
  • All CherryMAX® Rivet grip lengths
  • All CherryMAX® Rivet sleeve/stem material combinations

Locking Collar

  • The CherryMAX® Rivet features the "Safe-lock" Locking Collar which enhances joint integrity and reliability.
  • The "Safe-lock" Locking Collar is preformed on the stem during a sub-assembly operation, then deforms into the rivet sleeve head recess during installation, locking the rivet sleeve and stem together.
  • The "Safe-lock" Locking Collar is visible and inspectable after installation.
  • The "Safe-lock" Locking Collar installs flush with the rivet sleeve head.
  • The "Safe-lock" Locking Collar has been approved by several OEMs for use in engine inlets and components.

Rivet

The CherryMAX® Rivet is available in both nominal and 1⁄64" oversize shank diameters and is available in four material combinations:

  • 5056 Aluminum Sleeve/Alloy Steel Stem (50KSI Shear)
  • 5056 Aluminum Sleeve/Cres Stem (50KSI Shear)
  • Monel Sleeve/Cres Stem (75KSI Shear)
  • INCO 600 Sleeve/INCO X-750 Stem (75KSI Shear)

Tooling Simplicity

  • Lightweight, non-shifting installation tools require no adjusting.
  • Limited access capability with Right Angle and Offset Pulling Heads and Extensions for greater reach and "Split" tools for special applications including automation and robotics.

Bulbed Blind Head

Provides a large bearing surface area on the blind side of the structure, giving dependable results, even when installed in difficult thin sheet stack-up applications.

Part Numbering System

Part Number Example: CR3  24  2  -6  -04

CR3
CherryMAX® Rivet
24
Rivet Type & Material Combination - see Product Catalog
2
Head Style
  • Odd Number = Protruding Head
  • Even Number = Flush Head
-6
Rivet Diameter in 32nds of an inch (-6 = 6/32 = 3/16)
-04
Maximum Grip Length in 16ths of an inch (-04 = 4/16 = 1/4)

Head Styles

Universal (MS20470)

For protruding head applications. Available in both nominal and oversize.

100° Flush (MS20426)

For countersunk applications. Available in both nominal and oversize.

100° Flush (NAS1097)

For thin top sheet, machine countersunk applications. Available in nominal only.

Unisink

A combination flush and protruding head for use in very thin top sheets. Eliminates need for double-dimpling. Available in oversize only.

120° Flush

A large diameter, shallow flush head providing a wide bearing area in thin top sheet applications. Available in oversize only.

Diameter

Bulbed CherryMAX® rivets are offered in 1⁄8" (-4), 5/32" (-5), 3/16" (-6) and 1⁄4" (-8) shank diameters. They are available in nominal and 1/64" oversize. A gold colored driving anvil identifies nominal diameter. A silver colored driving anvil identifies oversize diameter.

Grip

The grip range of all CherryMAX® rivets is in increments of 1/16", with the last dash number indicating the maximum grip length in 16ths.
For example, -04 grip rivet has a grip range of 3/16" (.188) to 1/4" (.250).

To determine the proper rivet grip to use, measure the material thickness with a Cherry 269C3 grip selector gage, as illustrated in the diagram and the video tutorial. Always read to the next higher number.

Mechanical Properties*

Materials Ultimate Shear Strength Maximum Temperature
Sleeve Stem
5056 Aluminum Alloy Steel 50,000 psi 250° F
5056 Aluminum CRES 50,000 psi 250° F
Monel CRES 75,000 psi 900° F
Inco 600 Inco X-750 75,000 psi 1400° F

*At room temperature

Rivet Diameter Sheet Thickness Single Shear Tensile
Aluminum Monel Inco Aluminum Monel Inco
Nom. O/S Nom. O/S O/S Nom. O/S Nom. O/S O/S
3212 3242 3522 3552 3852 3212 3214 3242 3522 3524 3552 3852
3213 3243 3523 3553 3853 3213 3224 3243 3523   3553 3853
3214 3245 3524 3555   3222   3245     3555  
3222 3246   3556   3223   3246     3556  
3223 3252           3252        
3224 3253           3253        
  3255           3255        
1/8 (-4) 2 x .156 664 814 995 1220 1220 285 250 345 400 360 490 570
5/32 (-5) 2 x .187 1030 1245 1545 1865 1865 445 390 530 635 555 740 860
3/16 (-6) 2 x .219 1480 1685 2215 2525 2525 635 560 710 890 800 1000 1160
1/4 (-8) 2 x .281 2615 2925 3920 4390 4390 1125 1000 1260 1570 1410 1755 2030

Information in this document is subject to change without notice. Other products and companies referred to herein are trademarks or registered trademarks of their respective companies or mark holders.

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