Chris Bacon wrote:
I need 240mm M8 coach bolts (or roofing bolts). These do not seem to be
available.

If I use studding (threaded bar), how can I make a coach bold styne
domed head on one end?

Any other ideas? These to join concrete uprights of sectional building.

Everything is available.

I have an Italian hardware store, that stocks all sorts of weird stuff.
If I need a #7x1" wood screw, they have it. The big box stores never
stock non-standard sizes.

I have a fastener store, and they'll just flip open the catalog
and order in for you. A couple days later, you'll have your item.
That's the place I go to get stainless fasteners (because they're stock).

There's also a machine shop near me, and they can order in for
you too. There's no customer area there, but at least you can
walk in and talk to someone. That's where I go, to get taps
or dies, and expect them to be a stock item.

When the insurance comes, and they're trying to figure out
why the building fell over, that's not the time for the
threaded rods to poke out from the rubble.

Paul