On Mon, 24 Mar 2014 00:16:34 +0000, Dave Plowman (News) wrote:

If the ally frame is only 1.5mm thick I'm not sure it's worth bothering
with a lock. ;-)

That appears to be the thickness of the walls of the hollow section of
the frame, which seems robust enough to form a rigid door, but does make
it unsuitable for tapping a thread.

You can buy a Silverline tool for rivnuts for not a lot (I've got one).
It's quite hard work to use, but gives satisfactory results for the odd
one or two, especially on the smaller sizes. If you were doing lots
you'd want one with more leverage.

OK, I've decided to get a different type of lock now, but I'll bear that
in mind. I did notice somebody mention cheap tools in the Amazon reviews
for rivnuts, but said that they got better results by screwing a bolt
through, then holding the bolt in place with one spanner while using
another to tighten a nut down onto a couple of washers on the rivnut.