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From the Force 12 Catalog (1999 Product Line), page 5: "The rivets used by Force 12 are from the aircraft industry and are called 'closed end' rivets, since they are solid aluminum, with no hole. They are designed specifically for applications with vibration." From N6BT's writeup on TowerTalk reflector in 1997, http://lists.contesting.com/_towertalk/1997-March/003911.html: ..... The most common variety of blind rivet is found at the local hardware store. These are a "regular" type construction. This means that the mandrel (the shaft that is pulled by the tool) goes through the rivet body and is attached to a ball at the far end of the rivet body. This is the end inserted into the hole. When the tool is used, the mandrel is pulled outward, pulling the ball along with it. This ball will mash the part of the rivet body that is inside the hole (inside the tubing) up against the inside wall of the tubing. It will continue to do so until the pulling force is sufficient to dislodge the mandrel from the rivet body. Different mandrel designs will pull the ball into the body and leave the ball filling the hole; another is a pull-through, leaving a clean hole; another will leave a portion inside the body to increase shear strength; another will flare the material; another will fully core and spread out a lage portion of the inner surface. The ones usually found are the type that separate from the ball and leave the ball mashed up inside the rivet body. Sometimes, the ball will fall out and rattle around inside an element, so be sure you tilt an element to clean it before putting it up! Please note that the ball material can be important. If it remains inside the rivet, it is most likely participating in the joint. For elements, if the ball falls out, or rusts away, the joint is probably still intact, as the material has been seated firmly into the hole during assembly. Another type of blind rivet is called a "closed end" rivet. This is what Force 12 uses. They are designed specifically for connections where vibration is a primary concern. The closed end rivet has a hole only going part way into the body. The mandrel is attached to the outside (top - towards the rivet head) of this material. After the rivet is inserted into the tubing, the mandrel is pulled. As the pressure increases, the material completely fills the hole, plus pulling tight against the inside of the tubing. When sufficient force has been applied, the mandrel pulls apart from the body. This leaves a solid "hole" and the mandrel is completely removed from the body. The connection has high shear strength and might even be watertight. .... 73, dale, kg5u > -----Original Message----- > From: WA2BPE [mailto:wa2bpe@infoblvd.net] > Sent: Wednesday, September 11, 2002 08:49 > To: Dale L Martin > Cc: TowerTalk Reflector; Force 12 Reflector > Subject: Re: [Towertalk] C3 Rivets > > > I do not have much acquaintance with the Force 12 products, but > am wondering if the pop rivits shipped > with a new beam are the closed end (sealed) type. This could > explain *some* of the cost differential. > Anyone know for sure?? > > Tom - WA2BPE > -------------------------------------------- Force12Talk mailing list provided as a service by Force 12 Antennas, Inc. Force12 Web Site: http://www.force12inc.com To Submit Message to the List: Force12Talk@qth.com To unsubscribe and view the Message Archive: see http://qth.com/force12/list For problems with the list: contact n4zr@qth.com |
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