[sdiy] Tool for fitting 3.5mm jack sockets

[Seb Francis]

Hi,

I'm wondering if anyone has ever seen a tool designed for tightening the 
knurled metal ring that fixes some types of jack socket like the 3.5mm 
one in this picture:
http://www.rapidelectronics.co.uk/i/20013001.jpg

I'm having to fit very many of these to a plastic panel and it's very 
difficult to do so with pliers without:
(a) marking the plastic around the metal ring by holding the ring too low
or
(b) making a big scratch in the plastic panel when the pliers slip off 
because the ring is held too high

There are 2 slots in the metal ring, so there must be some kind of tool 
that fits this, but I have looked everywhere and can't seem to find 
one.  Any help would be much appreciated :)

Thanks,
Seb