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Drilling through steel/metal/colorbond

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...

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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

https://www.workshop.bunnings.com.au/discussion/comment/10627#Comment_10627

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

https://www.workshop.bunnings.com.au/discussion/comment/67673#Comment_67673

@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

https://www.workshop.bunnings.com.au/discussion/comment/96675#Comment_96675

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

https://www.workshop.bunnings.com.au/discussion/comment/114968#Comment_114968

@lozandsam,

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

Mitchell

ProjectPete

https://www.workshop.bunnings.com.au/discussion/comment/125301#Comment_125301

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

https://www.workshop.bunnings.com.au/discussion/comment/14225#Comment_14225

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

Noyade

https://www.workshop.bunnings.com.au/discussion/comment/114968#Comment_114968

"I'll take a photo this afternoon of my drill bit to see if you can identify any issues."

That would be interesting to see. Based on your experience, there has to be something wrong with the drill bit.

Did you try another 4mm drill bit?

Noyade

https://www.workshop.bunnings.com.au/discussion/comment/16124#Comment_16124

As Eric mentioned - a punch might be useful prior to drilling. But the 5 minute story is clearly excessive....

If there is wood behind the corrugated iron I tend to use this. The wine is just a bonus.

r23on

https://www.workshop.bunnings.com.au/discussion/comment/69670#Comment_69670

For all sheet metal twist drills are a waist of space they catch and rip the sheet a very smart person designed step drills and bunnings has a range of cheap to not so cheap step drills They can be used for a wide range of tasks including drilling plastic.

https://www.bunnings.com.au/craftright-3-piece-step-drill-set_p0027584

https://www.youtube.com/watch?v=KBrjkqPpVvo

Noyade

https://www.workshop.bunnings.com.au/discussion/comment/98477#Comment_98477

"For all sheet metal twist drills are a waist of space"

Gonna have to disagree mate. 🙂

Experiment...

Cheap drill bits.

Cheap cordless (10.8V) Aldi drill - set to high speed.

1.5mm sheet metal.

Two 4mm holes drilled in 24 seconds.

Experience - priceless!

There has to something quite wrong with the opening poster's drill bit, as surmised by Mitchell on the previous page.

r23on

https://www.workshop.bunnings.com.au/discussion/comment/115984#Comment_115984

Thats the beauty of this forum everyone has the opportunity to provide information and experience, a step drill 4mm set in cheap drill at heigh speed same thing no possibility of catching

Cloverleaf

Hi Lozandsam,

I feel your pain and frustration with drilling into colorbond sheets/post, BUT I did some out of the box thinking and came up with a winning recipe.

For the issue with the sheet: I laid them down on the ground, put a piece of timber under the area where the hole would be, got a decent-sized nail, and with the hammer, I wacked the nail just once, sharp and solid, and bingo a hole was created.

For the colorbond fencing post, I used hex head roofing screws and just drove them into the post. The screw did the job, when I removed it there remained a whole.

It worth trying, and costs next to nothing. (sorry Bunnings)

EricL

https://www.workshop.bunnings.com.au/discussion/comment/57199#Comment_57199

Hello @Cloverleaf

Welcome to the Bunnings Workshop community. It's sensational to have you join us.

Thank you for sharing your knowledge and experience in regards to creating a hole in Colorbond sheeting.

Were keen to hear more about all your projects and plans around the home and garden. Please feel free to reach out whenever you need assistance or would like to share a project with the community.

Eric

r23on

without going into the technical aspect of drill bits there are several things that need to be taken into account the drill speed the material to be drilled so

1. the smaller the drill the faster it has to go ie a 4mm drill need to spin faster than 12mm bit reason the point of the bit will chip ( subject to material being drilled .Hence the larger the bit the slower is must go. There are a number of charts available on the net that details this.(boils down to actual point speed ie the point spins slower than the outer diameter cutting edge )

Points - the drill bit you buy is set at an angle of 118deg for drill a range of materials for harder metals l an angle of 135deg these are fundamental rules which can be fount on charts found on the net

There are a range of angles for all materials that can be found on charts on the net

The other aspect of the drill bit is how wide is the cutting point with sheet metal a relived point is better to drill with.

i suggest that if you have an interest look up drill bit angels for all materials and timber suffers the same issues

it must be kept in mind the drill bit you buy is sharpened for drilling a range of materials hence 118deg including cobalt drill bits

I am sure there are number of engineers reading this would agree

Best of luck for further drilling

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