Drilling into a steel beam

[stavros.london]

Hi forumites,

I need to attach a 70mm by 200mm 1 meter lengths of timber underneath a large 200mm by 200mm 5 meter steel i-beam in order to make up for the difference between the sliding door height and the structural opening height.

My engineer suggested I can drill as many holes as I need on the bottom flange in order to bolt the timbers with m10 bolts without affecting structural integrity (as long as they are within a specific line not too close to the web or the tip).

My question is: is there any specific kind of bolt I should use? Also, without a magnetic drill or one of those guns, is patience and good quality hss drill bits the way to go or does anyone here have any hints?

Thanks in advance!

 

[cjard]

Hilti gun and nails just long enough to poke out of the flange when the wood is nailed up. Maybe consider making a T shape by fixing timber to 25mm marine ply first, then nail the ply up, that way you dont need outrageously long fixings (hilti fixings probably dont go that long anyway)

You can also get self drilling screws that will do the trick and probably faster than a drill bit (by the time it's done a few holes and is getting worn, or you are)

Going the drilling route though, i'm fair certain you'll eventually wish you'd used a hilti gun; I did the same thing as you for my first door mounted under a steel, and used SD screws. The other 4 doors were nailed in the same total amount of time as took for the first one

Using a hilti is a bit of experiment to get it consistent. The angle is critical as is the holding force. While inexperienced you'll find that your first nails either pound right through the wood or barely penetrate at all; grinder....

 

[^woody^]

Yes, a nail gun and ear plugs.

 

[stavros.london]

Based on engineer's instructions the holes have to be relatively precise, plus I don't own a nail gun, so, back to drilling, I'll use a drilling lubricant and the dewalt extreme hss drill bits and see how it goes...

 

[XtraRaptor]

Based on engineer's instructions the holes have to be relatively precise, plus I don't own a nail gun, so, back to drilling, I'll use a drilling lubricant and the dewalt extreme hss drill bits and see how it goes...

Start with a 4mm bit, then increment up in 3mm steps, easier on you, the drill and easier to drill first hole in the correct position.

 

[cjard]

There are these things called hire shops? A hilti gun, nails and cartridges was 45 quid for a week's hire from my local independent. They only expected the gun back so the next time I needed, i just hired it for £25. Versus paying a trade to spend all day drilling holes and knackering drill bits it seemed like a bargain. The ply took minutes to fit, hiltis are precise because you position, push the tip in and then squeeze the trigger

 

[stavros.london]

Just to close this one, here's what I did in the end:
- bought an 12mm mag drill bit and a beer for my builder who kindly came over with his mag drill and we did 8 holes in the inner half of the bottom flange in 10 minutes for the M10 bolts

- got some 109mm long techfast heavy duty self drilling torx screws for the outer half of the bottom flange. These things are just great! I did find that they go through much much easier if there's a preexisting 3mm hole, which is very easy to do with an HSS bit even in the 13mm section steel I had. After that the self drilling screws go through in a matter of a few seconds.

Overall this worked out great in the end, and if the builder wasn't available for the mag drill, I would have just used the self drilling screws on that side of the flange as well.

Thanks to all for the responses.

 

[Ian H]

What beer did you use?