How do I drill into an existing galvanized fence post?

Question

I have an existing metal fence post, set in concrete, in which I'd like to drill a new hole in that post.

Normally, I would use a drill press to drill into a curved surface like this. Since the post is already set in concrete, this is not a viable option.

Is there some sort of guide jig or other tool or process to make this task easier? I'm having quite a time drilling even a small pilot hole.

bib · Accepted Answer · 2014-01-31 18:19:52Z

5

The punch suggested by SpectralGhost is a good idea.

If that doesn't work, you can make a jig with three pieces of 2x4.

pipe jig

Screw the pieces together and drill a pilot hole for the drill bit (the dotted line) using the same size bit you intend to use on the pipe.

answered Jan 31 '14 at 18:11

bib

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this seems like a great idea. i'll be trying this asap. thanks! – nullrevolution Jan 31 '14 at 19:15

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UnhandledExcepSean · Accepted Answer · 2014-01-31 17:45:33Z

7

I would use a punch to make a small dent in the pole so my drill bit wouldn't slip.

answered Jan 31 '14 at 17:45

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3

Center punch with a sharp 60 degree tip to guide the drill bit, you want a nice conical guide for the bit. Use a small drill to drill a pilot hole as it will be less likely to jump out of the center punch divot, finish out with full size drill bit. Many's the annoying non-flat surface I've had to do, it's all in the start. Make sure the centerpunch has a nice sharp, hardened tip. The usual failure with this method is to use an 20 year old punch that now has a ball tip due to lack of maintenance. – Fiasco Labs Jan 31 '14 at 18:34
i should have mentioned in the question that i've had trouble with the punch method. and i suspect that Fiasco Labs is correct: my punch is far from new and is not terribly sharp. +1 for the thoughts. – nullrevolution Jan 31 '14 at 19:10
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I would add, start at a slow speed and just enough pressure to keep the drill bit cutting. – mikes Jan 31 '14 at 20:09
I would also add that you need to ensure that your drill bit it sharp and that the drill edge is well centred, there are different cutting patterns for differing applications, and when you diy sharpen drill bits, you may get an offset cutting edge, trying to drill in one specific spot is then a challenge! – Hightower Oct 15 '14 at 6:42

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2 Answers 2