fixing to flange of RSJ / self tappers

Tek screws.

There are washers for just this sort of application, They are simply called tapered washers and are D shaped where the straight edge of the D is the thinnest side and the round side gets thicker to the middle. You fit them when there is a taper so that the thin side points to the web of the RSJ.

I'll be interested in them as well.

Dave

Dave

Have you though about some of the more advanced constructional adhesives available nowadays?

That's a nice idea, I agree that through fixing is the way to go, thread forming in something that thick and tough is a complete ball ache.

My suggestion was going to be drilling a clearance hole and screwing into a batten on the inside of the web, no need to taper it, just screw into it slant.

Good point. I actually have timber bolted into the web anyway ! I can just drill a clearance hole through the RSJ and screw through. With some of the thin screws around (e.g. drywall screws), 3-4mm would be enough. Dunno why I didn't think of that before :-) Simon.

I would not bother. WE just whacked some shaped timber in with a large mallet, and a bit of foam round it. And used that to mount the cladding off.

In article , Simon writes

Can I interest Sir in some wheels I reinvented earlier this morning :-?

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Dave Baker" saying something like:

I guess if a tapping tool can cut a thread a screw could ? I was told this is possible but I'd like to see it. Mind you I find it hard to believe the hilti guns can nail to an RSJ !

In the end I drilled clearance holes and screwed into timber the other side of the flange.

Cheers, Simon.

In message , Grimly Curmudgeon writes

You might get away with it by counter boring the fixing holes such that there is only one threads worth left. Tricky to do up in the air:-)

I would forget the self drilling attribute.

regards