Tips for drilling through metal?

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Old 08-16-19, 08:37 AM
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Question Tips for drilling through metal?

I recently installed some cameras on an industrial metal building and had one hell of a time drilling holes into the steel structure for the mounting screws.

I assume the area I was trying to penetrate was 1/8". I was using brand new titanium bits but I ended up having to mount the brackets to some nearby sheet metal instead.

I'm not sure what I was doing wrong so I am hoping someone with more experience in drilling metal can give me a few tips. Drill bit type, drill type, etc.
 
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Old 08-16-19, 09:47 AM
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I use to use titanium bits for dripping but found they tend to be a 1 hole then toss or sharpen.
I switched a couple years ago to these cobalt bits which worked a lot better, held an edge longer, and was able to still sharpen them on the bench grinder.

If doing larger holes, a uni-bit worked for not so clean but fast holes, or proper metal hole saw bits for cleaner holes (not the bi-metallic crap). I will try to find some links to post.
 
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Old 08-16-19, 10:17 AM
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Here are the bits I've been using, mostly for camera installation incidentally.
We installed 32 or 33 cameras in an all steel industrial building. Bought this kit before starting the job and only killed 1 bit (broke it as I was leaning a bit on the bit, my fault).
I'm sure there are similar or the same kit south of the boarder. Since using these, I'll never buy titanium bits ever again.
https://www.canadiantire.ca/en/pdp/m...0658p.html#srp
 
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Old 08-16-19, 11:33 AM
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So lets do some simple math.

The kit in the link has 100 pieces for $109 so that's about $1.01 each.

I just looked up the cost of the "jobber" bits we use in the shop for drilling steel.

For a 1/4" dia bit they run from $2.50 to $7.93 each.

I think we can say those bits might work ok for wood, but not for metal!

If drilling metal you need GOOD bits because the throw away wood bits will cost more in the long run!
 
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Old 08-16-19, 12:11 PM
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Its more the frustration than cost for me. If I'm killing myself and my drill because the bits are as sharp as a politician, I'm having a bad day/job.

On a side note with the bits I linked, I bought them on sale. Canadian tire tends to over price stuff like bits, then through them on sale for much lower. $109 regular price, I paid $39.99 on sale and I'm guessing money was made.

I used those bits for just over 2 years (same kit) before changing careers (again).
I'm still using these bits for the large home renos, but is not as frequent as when I was a trades guy.
 
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Old 08-16-19, 01:53 PM
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"Titanium" bits sounds like Harbor Freight Tools. It has been my experience (and a whole lot of other people agree) that any HF cutting tool is at best good for one use and often not even good for that.

I agree that cobalt drill bits are probably the best for drilling hard material.
 
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Old 08-16-19, 02:32 PM
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Thanks for all the suggestions guys. Looks like cobalt bits get the unanimous vote here! I believe I got the titanium ones off of amazon but the quality is probably on par with HF.

I seriously don't care if the bits only last me to the end of each job as long as they don't have me feeling like I am the one doing all the work.

I always find myself saying get the right tool for the job and I guess in this case it means more than just a good drill.
 
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Old 08-17-19, 05:33 AM
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Make sure the drill bit has sharp cutting edges and is for use on steel, rotating at reasonable speed ( drill has time to cut a continuous chip) and use lots of cutting oil (reduces friction). Applying cutting oil while drilling may require a helper.
 
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Old 08-17-19, 06:15 AM
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I got the lecture years ago from a good friend that worked in our company machine shop, you need the right drill for the material you are drilling.

I didn't hear any comments about the angle of the drill point or the benefits of a pilot hole. I searched for a related link and this one looked good, better than anything I could write up.
https://www.regalcuttingtools.com/le...uld-i-be-using

I have probably 40 1/8th inch drill bits as they are my pilot drills. The tip of larger drills is flatish and it makes it hard to start a hole. Drilling a pilot provides a start and gets the cutting edge working with less pressure. Larger pilot holes are needed for larger drill bits.

For wood just about any drill will do, but for steel you want a drill bit intended for that purpose.

Bud
 
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Old 08-17-19, 06:46 AM
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We often service pylon signs at commercial buildings and many cases the existing screws break off as they are so corroded. To reattach the signs we use Tek 5 screws. These will plow through 1/4" steel like butter.
 
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Old 08-17-19, 07:50 AM
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Thanks for the new replies. Very helpful tips.

Tolyn, I think I will pick up some of those Tek 5 screws. Even If I cant use them for all applications it sounds like they will come in handy!
 
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Old 08-18-19, 11:08 AM
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Like the others have said, cobalt is the way to go. I bought a few Bosch cobalt bits and am still on the first one. To give you an idea of their durability I drilled lengthwise through some Grade 5 bolts and that first bit is still going. As far as lubrication of bits at odd angles, try cut ease stick lubricant. Although it thins out once things warm up, it stays in place much better than any liquid oil.
 
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Old 08-18-19, 05:25 PM
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Thanks, Rick, looks like amazon carries that cut ease stick lubricant.
 
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Old 08-18-19, 05:40 PM
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Tek 5 screws
Tolyn, do you happen to know what brand or what the Tek 5 screws you get are made out of? I'm seeing ones on amazon but they state they are for sheet metal and are made out of various metals.
 
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Old 08-19-19, 01:59 AM
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These days almost any drill made in the USA is a premium quality and does quite well. Most drill sets I've tried from HF are junk and in the large set they aren't even different sizes. So, #28, 29 and 30 can all be the same size. I've had good luck with these bits but they are not the cheapest.
 
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Old 08-19-19, 09:11 AM
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Originally Posted by rufunky
I am hoping someone with more experience in drilling metal can give me a few tips. Drill bit type, drill type, etc.
Most important things
-cutting oil
- slow drill speed
-slow feed rate

One trick for drilling a vertical hole-
To keep the cutting oil from just running down the wall, place a bar magnet just below where you are drilling to create a "shelf" to retain the oil. For round stock, flexible refrigerator magnets work.
 
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Old 08-19-19, 11:25 AM
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Originally Posted by Pilot Dane
Most drill sets I've tried from HF are junk and in the large set they aren't even different sizes. So, #28, 29 and 30 can all be the same size. I've had good luck with these bits but they are not the cheapest.
Question - has anybody here tried case hardening their drill bits?
Either old dull ones or cheap HF drill bits?

My dad worked at US Gage and knew his way around the machine shop,
IRC, the process was:

1) Heat to red-hot and quench in old motor oil,

2) Reheat to just below red hot and quench in old antifreeze.

3) Polish the surface. Check the polishing by dropping the bits into a glass of beer and look for bubbles nucleating at rough areas; repeat as necessary. Supposedly, draft-nitrogenated beer is better for this than canned-carbonated beer. (apparently, you could get away with quite a bit if you were a mechanical engineer circa 1965...)

4) Rust proof by dipping the drill bits into old battery acid to clean them, when the bits are done fizzing pour a layer of old motor oil on top of the acid. Lift the drill bits through the oil layer slowly so the oil coats the metal before it gets exposed to the air.
 

Last edited by Hal_S; 08-19-19 at 11:57 AM.
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Old 08-20-19, 04:10 AM
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Case hardening a drill? Just buy a good drill bit unless you are looking for a project. For me it's usually not even worth the time to re-sharpen the smaller ones let alone getting into case hardening.
 
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Old 08-20-19, 05:07 AM
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Case hardening a drill? Just buy a good drill bit unless you are looking for a project. For me it's usually not even worth the time to re-sharpen the smaller ones let alone getting into case hardening.
I agree and not. For normal use, even light trade use, yes. When I was an installer, my drill was always used as where my bits. I use to spend more money per year on bits and a new drill per year than anything else in my tools.
 
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