Drilling through steel/metal/colorbond

[lozandsam]

Had a go at putting together a colorbond fence over the weekend, while we got the job done, each hole I had to drill took a good few minutes each. I've watched just about every tutorial for drilling through steel and it just seems to go straight through alot easier than I was doing it, what am I doing wrong?? I'm just using a standard cordless drill (which from what I can gather is all I need) and a heavy duty cobalt bit. I'm pre drilling each hole, then using self drilling tek screws to fasten. Am I not using the correct tools?

It turned a relatively easy job into a full day mission because the drilling just took so long...

[MitchellMc]

Hi @lozandsam,

Drilling steel needs to be done at a relatively slow speed with pressure on the drill. If you have the drill on high speed at max RPM you'll quickly dull the cutting tip of even a cobalt drill bit by rounding it over. This is the most common reason I have seen for a drill bit not drilling correctly. 

Did you need to pre-drill first? Were the self-drilling tek screws having issues penetrating as well?

Mitchell

[lozandsam]

Hi Mitchell, thanks for the response! I thought I was drilling slow enough but perhaps need to ease up even more. And yes, I had no chance of getting the tek screws to penetrate prior to pre-drilling when i tried. But again, I understand that I should not need to pre-drill with this type of screw?

I was using a regular cordless drill & 4mm heavy duty drill bit (and the screws that were supplied with fencing gear). Can you confirm it's all in 'how' its done and nothing to do with what I was using?

[MitchellMc]

@lozandsam,

If you were not drilling at maximum RPM's, on the high-speed setting, then I suspect that speed wasn't the culprit. Was the Colorbond flexing at all? Sometimes if the steel is not solid a drillbit struggles to bite into it with the cutting tip and just spins on the surface.

Enough pressure might not have been applied to the drill. However, not an incredible amount of force is needed and I'm sure you were likely pushing quite hard given the drill bit not working well.

I've just taken my cordless drill and an old 4mm dullish rusty drill bit and put holes in a variety of Colorbond material including flashing, roofing and a 3mm thick post. The drill bit took a fraction of a second to go through the steel.

If you can upload a closeup image of the cutting tip I can tell you if it has been domed over from high speed and friction. The other possibility is that you just have a drill bit that wasn't sharpened correctly. I have never really seen this before but I wouldn't rule it out completely.

A regular cordless drill and a cobalt drill bit should be more than adequate for the job.

Mitchell

[lozandsam]

I'll take a photo this afternoon of my drill bit to see if you can identify any issues. It was the posts themselves I was struggling to drill through, like to connect the top rail to the post, each hole took about 5 minutes to drill which i'm assuming is way too long ha

[MitchellMc]

@lozandsam,

Definitely shouldn't be taking 5 mins. Let me mention @ProjectPete as he is quite familiar with constructing Colorbond fences.

Mitchell

[ProjectPete]

I'm not much help here as I've never had an issue and everything @MitchellMc said is what I would've said.

Constant pressure at a slowish speed with a self drilling screw is all you need to go through Colorbond with no pre-drilling required @lozandsam . An Impact Driver is the most ideal drill for the job, but a Drill Driver is still sufficient.

[Thisbloodyfence]

Omg I feel you! Same problem every time I try drill a hole! 

Looks so simple, but it's just dang painful. 😬

[EricL]

Hello @Thisbloodyfence

Welcome to the Bunnings Workshop community. Thank you for joining us and sharing your thoughts on drilling through steel.

I totally agree with you, it is quite frustrating at times when trying to drill through steel and the bit starts shifting from its original spot. My tool specialist at the store suggested using a Finkal 6.5mm Round Head Centre Punch. It makes a tiny dimple in the steel and guides the drill bit and prevents it from drifting. If you need more information, please let us know.

Eric

[kel]

hi@loanzandsam,

i know this is an old post,but i have suffered the same problems and broken many a drill bit.i suggest anyone drill thru steel,to buy a set of step drill bits.a set of 3 for $20 at bunnings,these bits will drill thru steel with ease,they will save you time,frustration and the need to replace broken drill bits.

cheers kel