I'm assembling a corrugated sheet metal fence and I have installed the posts and attached the pieces of shaped tube (rectangular cross section) horizontally and now I need to attach the metal sheets to the shaped tube. I'm now using a handheld drill with a regular drill bit for metal to drill the through holes in the tubes (I'll use screws with nuts later).

Drilling is a huge pain. First, the tube is only attached to the posts and so it bends when I press the drill onto it. Second, the drill bit will not dive into the metal unless I use a punch which is not a convenient option because I need to first put the sheet onto the tube and once I do that I'll have to punch through the sheet. Finally, even if I drill one wall of the tube the drill bit will then not dive into the other wall - it will be "running" for a while and the side surface of the drill bit will route the hole in the first wall. The result is really ugly and drilling takes a lot of time.

How do I drill through the shaped tube conveniently?

2 Answers 2


One option especially suitable for this scenario (outdoors, often drilling above your head, with the tube bending and vibrating, using handheld drill) is using special drill bits tailored for fast drilling into sheet metal. The market has numerous offers, including Irwin Turbo Max, DeWalt Extreme 2 and Ruko Fast Cut - the idea behind all those is that the drill bit looks similar to a drill bit for wood and the small tip of the drill bit helps the drill bit dive into thin metal.

One important thing is that you should not proceed to drilling the second wall until you retracted the bit from the hole and checked that there's no metal on the tip. Otherwise the following can happen: the drill bit will burst through the first wall and the metal which the tip was facing will remain on the tip and prevent the tip from contacting the second wall.

Beware of the following downsides:

  • these are next to impossible to sharpen in your workshop - prepare to either throw them out or grind them into "regular" shape bits once they get dull
  • the price is notably higher compared to "regular" bits
  • the "metal on the tip" problem described above
  • not that easy to find in an average store, so you should shop in advance

Wouldn't self-drilling tapping screws be good here? It seems to be the thing to drill through the sheet meal and straight into the flat face of the rectangular stock. The ones in this link are only zinc plated, http://www.asmc.net/10x5-8-Sheet-Metal-Screw-Unslot-Hex-Washer-Hd-Self-Drill-Zinc-Plated-Pk-50/ . I have used types that are galvanized that are similar to the ones in the link.

  • 1
    I tried those once - they seem really dull and take a while to drill into the tube wall.
    – sharptooth
    May 6, 2014 at 12:13
  • Going with a decent brand is a good start, and the gauge of metal is another thing. I have used these with great success. The horizontals you are drilling into, as long as the wall thickness is not much over 1/8" should go quickly. At least, IMHO, it is faster than drilling, swapping out drills or drill tips, wrenches or sockets... One drill with driver tip does it all, no wrenches needed.
    – Jack
    May 6, 2014 at 21:35

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