Cherry Aerospace

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.

CherryMAX® Rivets consist of four components, assembled as a single unit:

A fully-serrated stem with break notch, shear-ring and integral grip adjustment cone.
A driving anvil to ensure a visible mechanical lock with each fastener installation.
A separate, visible and inspectable locking collar that mechanically locks the stem to the rivet sleeve.
A rivet sleeve with recess in the head to receive the locking collar

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.

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	Ultimate Shear Strength	Maximum Temperature
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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Installation