Self Tapping Screws to Steel 2

[Jerehmy]

A project is underway and I was told to look at the handrail connections way too late. Like its being built right now.

One of the connections has the handrail terminating at a 6" tube column and calls for a Hollander bracket to be bolted to the column. The detail doesn't show the bolts going all the way through and they don't want them to be bolted through. A bolt won't work here since nothing would stop it from pulling out.

I don't know much about self-tapping screws into steel other than cold form sections. I did a little research but can't find any 3/8" diameter stainless steel self tappers. Drill-Flex goes up to 5/16".

I don't know the tube column thickness, but they have very little load so its safe to assume they are 1/8" thick.

Is there any other type of screw/fastener that can make this connection other than bolting through?

Thanks.

 

[Brad805]

I see a couple 3/8" (

https://www.fastenal.com/products?r...:^"Imperial (Inch)"$|~ ~|attrdiameter:470|~).

They are not easy to install. Crews of ours installed hundreds of these ecospan screws (

http://www.ecospan-usa.com/advantages-shearflex.html)

thru joist top chords recently using 3/4" drive drills. They found that they broke off approx 15% of the screws during the install and that is standing perfectly straight above. These are approx. 3/8" diameter. I do not believe the installer was doing anything wrong and it would seem to be a common problem since Nucor sends a lot of extra screws. A broken tip could be a problem since they tend to be difficult to drill out (hardness differences) and I doubt your railing mount can move much. This is a simple case where the installer should tell you his preference.

Koot, Canadian Tire is where my tap set came from.

 

[Jerehmy]

Ron - figured out why I couldn't find them earlier. It's because I need stainless steel ones. The stainless only go up to 1/4" at fastenal.

 

[Spartan5]

When will the wall thickness of the column be known?