I'm trying to mount some security cameras on the sides of my home. I
have old steel siding on the house. The damn drill bits I buy today
can't get through the thin steel except once of twice without dulling
to the point of being useless even for drilling wood. I remember
decades ago I used to drill through angle iron and flat iron with no
problem. Are there any non-chinese drill bits that actually drill
through metal more than once or twice? The latest crap I bought were
made by Irwin.
On 12/04/2013 07:56 AM, email@example.com wrote:
I have no problem drilling through steel with even the cheap harbor
freight twist bits. I do, of course, use a drill press, with cutting
fluid, at the correct speed and pressure though.
If you are using a hand drill you are most likely not getting enough
pressure, not using a cutting fluid, and spinning the drill bits too
fast, resulting in a local hardening of the metal you are trying to
drill into (assuming steel), and dulling your drill bits.
You might have better luck with a step bit, but again, use cutting
fluid, put some pressure behind it, and spin it at the appropriate RPM.
Those are regular HSS bits, with a TiO2 coating (which is a dull gold in
color). The coating reduces friction, which reduces heat, leading to
longer life and faster drilling. You pay more for the coating than
regular HSS bits, though, especially if they are good quality to begin
You should not be having any trouble drilling through thin steel siding,
even with a high speed steel bit.
Right now, there are three different kinds of drill bits available on
1. High speed steel bits: These are the least expensive bits, but they
still should be able to drill through the mild steel used to make
2. Cobalt bits: These are made from a much harder steel so they stay
sharp longer and can be sharpened just like any other drill bit to
provide what is essentially a new drill bit. Cobalt bits have a dark
brown coating applied to them so that you can tell them apart from high
speed steel drill bits.
3. Titanium Nitride bits: These are regular high speed steel drill bits
that have an extremely hard titanium nitride coating applied to them,
giving them a "gold" colour. The extremely hard coating stands up
better to wear, so titanium nitride drill bits are much slower to dull
than either of the preceding two kinds of drill bits. However,
sharpening of a titanium nitride drill bit grinds off that extremely
hard coating at the tip of the bit, leaving you with what is essentially
a high speed steel drill bit; albeit a sharp high speed steel drill
You shouldn't have any problem drilling through sheet metal with any of
the above drill bits, but the cobalt and titanium nitride bits will give
you better performance than the high speed steel drill bits.
On Wed, 04 Dec 2013 14:06:04 -0500, Stormin Mormon wrote:
I used to work in a machine shop when I was a teenager.
I learned how to sharpen the drill bits on a grinder
from German-speaking professionals.
I don't remember the angles anymore, but, I can still
hold a bit with two hands, "just right", and then ease
it gently back and forth, up and down, with that slight
twist at the end, to sharpen them.
It's amazing though how much better the coated ones
> cobalt coated bits which may have a dark brown color.
So far as I know, ALL "cobalt" bits are made of cobalt steel, and are
solid cobalt steel all the way through. They are given a dark brown
coating only so that they can be readily differentiated from regular
high speed steel drill bits.
I have never heard of a "cobalt coated" drill bit.
Assuming you are up a ladder with a battery drill in hand, try this:
first, dent the hole site with a hammer and nail,
then put a blob of axle grease into the dent,
drill as slowly as you can.
Report results here.
On Wed, 04 Dec 2013 13:56:03 -0500, Stormin Mormon wrote:
I suspect they use them to save time.
It's my humble opinion that we, as homeowners, can do
a better job, because saving time and a few dollars
isn't our goal.
Our goal is to do a good job, so, it's my opinion,
we wouldn't necessarily follow the contractor since
they have different objectives (the bad ones anyway).
For example, on garage door torsion springs, they put in
the el cheapos, saving *them* a few bucks, but not saving
you anything (since it only costs a few bucks more for a
really good long-lasting spring).
Still, contractors know what the good stuff is when it
comes to glues and holders, since they know what they
have to repeat (which I'm sure they hate) under warranty.
So, for *that*, I'd follow the contractors.
On 12/4/2013 10:56 AM, firstname.lastname@example.org wrote:
I sent a young technician who worked for me to drill some mounting holes in
some steel racks. Nothing very heavy, i gave him a couple of new drill bits
along with the layout for where the holes needed to be. He came back in an
hour cursing the crappy drill bits I had stuck him with and he said that he
destroyed both bits drilling the first of about a dozen holes he was
supposed to make. The bits were good quality and I'd never had any trouble
with them but I grabbed a few more and went out with him to the equipment
shack so that he could show me what was going on. I checked that he had
marked and center-punched the holes properly and then set about drilling
the next one myself. The drilling went much faster when I demonstrated to
him that things worked fine when the drill was spinning in the _forward_
direction and not trying to burn through the steel by friction alone.
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