Dave Plowman (News) wrote:

Andy Burns wrote:

have ordered some A2 M5 rivnuts and a setting tool

I've got one of those kits and it's very useful. Not tried it in tube,
though. They're really designed for a flat surface.

I've bought some with countersunk heads

http://www.ebay.co.uk/itm/251202027233
http://i726.photobucket.com/albums/w...CSKheaddia.jpg

and some flat head ones

http://www.ebay.co.uk/itm/310543511992
http://i726.photobucket.com/albums/w...NUTDIAGRAM.jpg

Hoping the countersunk ones will work best, the internal deformed
portion will be what resists pulling-out, the reduced head will be less
good at resisting push-in, but that will be sandwiched between the
surrounding tube and the saddle-bracket, so should not be much of an issue.

I saw a suggestion that the flat ones could be peened over if necessary,
there are some inbetween small flat head ones too, but I didn't buy any
of those.