134a to r12/r22 male coupling

I have a R12/R22 vacuum pump that I want to use with my new set of 134a gauges
to pump down auto a/c systems. It would seem to me I need a male coupling to
hook up the 134a gauges which is female to the female (think 1/4") connection on
the vacuum pump. So do they make a coupling in those sizes and if so what size
should I say for the coupling. Better yet who or where can I purchase the
coupling?
thanks in advance for your help