mo brought next idea :

"Harry Bloomfield" wrote in message
k...
mo submitted this idea :
Very very good idea and pretty much perfect.

Any tips on how big a screw you would use for a 10cm post ?

You wouldn't use screws, you would use Rawlbolts - 8 or 10mm. No need to
counter-bore, just use threaded rod in the Rawlbolt, with a nut.

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http://www.screwfix.com/prods/44397/...35mm-Pack-of-5

That sort of idea, except I think in that version the threaded stud is
fixed to the stud, made as one piece - fine if the thread is long
enough. If not, get the type with a bolt rather than a stud and use
some threaded rod plus a nut in place of the bolt.

These would work with threaded rod...

http://www.screwfix.com/prods/20828/...OSFFQ?ts=01677

How do you install them?

The way they work is....

You drill a suitable hole, push the Rawlbolt in the tighten it up. The
process of tightening pulls the wedge shaped end into the sleeve
section, causing the sleeve to expand in the deepest part of the hole.

In the type intended for a bolt, the wedge part is a threaded nut.
Using these with threaded rod, you would insert the Rawlbolt in the
hole with the supplied bolt, tighten the bolt up enough to wedge
Rawbolt in place then remove the bolt to replace it with your threaded
rod. Doing it that way your threaded rod can be whatever length you
might need.

Do all three or four fixings first, then drill and fit your fence post
over the protruding threads.



Do they work like normal wall plugs? i.e get bigger as the 'screw' goes in?

Yes, but a much bigger and stronger fixing. A wall plug and screw tends
to expand most nearest the surface, whereas a Rawbolt's greatest
expansion is in the deepest part of the hole.

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Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk