large dzus fastener source?

[Don Marshall <marshall@nefcom.net>]

Amici:

Does anyone know of a source for the larger 3/8" dzus fasteners?  I need a
couple of the captive type that are permanently attached to the fitting and
spring out when they're unfastened.   None of the racer catalogs I have
list the bigger ones, although Pegasus specifically says they don't carry
them.  

Any suggestions would be appreciated.

Thanks,
Don Marshall