GD427 in action

GD427 in action

Saturday, 6 June 2009

Rivnuts & Jacknuts

In reading up on the tools needed to build this car I kept hearing about rivnuts and jacknuts. Well I've now got to the point where I've started using them myself. Rivnuts, rivet nuts or threaded inserts are the same thing just different terms used by different people. A rivnut works much like a standard pop rivet but instead of holding two panels together it's inserted just into one and leaves a threaded hole through the middle. This allows you to insert a bolt and either bolt another panel to it or maybe just a bracket, handle etc

The rivnut itself contains a thread and screws onto the mandrel, it is then inserted into a predrilled hole.

By squeezing the handles of the tool together, the mandrel is pulled back into the tool forcing the rivnut to deform and so griping the panel it has been inserted into. Then simply unscrew the mandrel from the rivnut using the knurled knob and you're left with secure place into which a bolt can be fastened.
Jacknuts are very similar but designed for weaker or brittle materials and perfect for GRP. When they deform they spread "fingers" to exert there grip over a much wider area. It is possible to use the same tool to insert a jacknut but care is required as a rivnut tool is designed to exert much more force than is needed for a jacknut. There is a similar but specific tool for jacknuts but it isn't up to the job of inserting a rivnut. Rather than buy both, I'll just have to learn to be careful !

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