Hang curtains on rsj problems

[davebeach]

Hi,
I’ve a 4M sliding door with a universal steel beam above it and I’m trying to hang curtains by drilling into the underside of the steel and affixing the mountings. I’ve bought HSS drip bits (dewalt) and self drilling (not self tapping) screws (4.2mm x 50mm). Nothing seems to work. This is a list of issues. I’ve so far drilled 3 holes with no success
1) self drilling screw wouldn’t go far enough in
2) I then created a pilot hole (3mm) upon which the head of the screw snapped offtwice leaving the shaft of the screw in the hole
3) drill bit then snapped
I’m using a drill to drill the pilot then using an impact driver to screw the screw. I tried a normal drill but the screw got stuck half way up…

Any help on which screw length / drill bits or links to the specific items would be really helpful

 

[freddiemercurystwin]

Drill a bigger hole, the screw only needs to be very slightly larger (say 0.5mm) than the hole to grip. A cheapy £5 Vernier caliper off eBay can be very useful in times like this to measure stuff (fairly) accurately.

 

[smashpotato]

Don’t use an impact driver either, as that puts to much torque on the screw. Try as above and use a bigger hole.

 

[davebeach]

Thanks
Should I still use a self drilling screw with a pilot?
Also is 50mm to long for the screw?
When I tried screwing with the drill, the screw stopped half way. I presume if I drilled a bigger pilot this wouldn’t happen?

 

[freddiemercurystwin]

Yes drill a slightly bigger hole, the length of the screw is determined by how thick the the fitting is and whatever's between the steel and the fitting, it only needs to go through the beam by a few mm. There is a sweet spot between the size of the hole, the screw and the power of your drill, as mentioned not an impact driver. You can probably screw it in by hand, drills typically don't have much torque for screwing stuff.

 

[davebeach]

It’s just plaster then plasterboard so 10-15mm thick? Will a screw 25mm be enough?

 

[robinbanks]

Pick up a tap and die set, drill the hole, tap a thread into it and use a bolt or machine screw rather than a wood screw

When selecting a drill size, use a tap sizes table then go up to the size of drill you have.. e.g. for an M4 tap you'd use a 3.3 drill if you have one, or a 3.5 you're more likely to have. (for M5 use 4.2 or 4.5, M6 use a 5)

If you don't have a decent set of drill bits, buy one when you get the taps

 

[freddiemercurystwin]

A reasonable solution for a competent DIYer, though seems a little excessive to buy a tap and die set, that's gonna sit on his shelf gathering dust for the next 40 years! Plus he might not be able to get the tap in if too close to the window. I've been looking for a cheap S/H set for a year or so, just can't justify buying one new for the once a year use it would get used.

 

[davebeach]

Thanks @robinbanks ! It worked! Interestingly I drilled through the metal with the drill bit (3.5) and tried the self drilling screws (4.2mm x 50m) and they the screw still wouldn’t go all the way in. So used the tap method with a machine screws (m4 x 40mm) and hey presto I now have a curtain rail up. Thanks again