Best drillbit for steel

[Kyle_in_Tex]

Chicago-Latrobe makes premium drills. Size your pilot drill a fraction bigger than your 5/8" drill's web thickness.

Clamp the crap out of your work piece. Get you some water based coolant and go to town. Don't overforce the feed, yes push on it so the drill doesn't rub, but don't hang your body weight on it. The corners of the cutting edge will wear first. Don't try to drill too much on each peck. Chipping usually occurs when you come back down on a chip left in the hole from the previous peck. Let the coolant keep the drill cool. Run about 30 surface feet per minute on a manual machine with coolant.

An iron worker hydraulic press will look mighty fine after your first hundred holes.



I hate hand sharpened drills because I'm spoiled.

 

[dragoneggs]

I too am in the camp of not having much luck with hole saws. Especially for a measly 5/8" hole. And especially in thicker stuff.

No way would I want to use a hole saw in 1/2" + material. Especially for holes under 1" diameter. But then again, I have always had access to good drillpresses, mills, lathes, mag drills, etc.

The OP is talking a 5/8" hole in 3/8" steel. Not sure bout a hole saw, but a with a 1/4" pilot and a good 5/8" twist drill, should take no more than about 20 seconds to make a hole.

LD, I am totally in line with you on this. Hole saws for me have always been large diameter and in wood! The cost of a twist drill is much less. Use oil and slow speed and save your money on a hole saw. My :2cents:

 

[Shield Arc]

I've had pretty good luck with hole saws. Chewed through 200-feet of rock with this one. But it had a 750-HP diesel engine turning it. :laughing:

 

[woodlandfarms]

So... First, thank you to everyone so far. Lots of great info.

As an update to the project, I was wrong. the holes needed to be 3/4 (Caught this before I drilled) and my steel is more like a thick 3/8" but my drill press runs too fast (500RPM on slow side) and the throat just didn't have the throw I needed. So I went with my large Milwaulkie Hammer Drill. Works like a charm, except for those magic moments when the bit catches and it is ripped from your hands, usually smacking you in the jaw as a friendly reminder to who is actually doing the work. Oh, I went with the normal high speed cobalt drill bit.



It brings me to my next series of questions. I want to get a speed control. JJ posted a link to a few and I see no reason either my drill press or my hammer drill would not run with this.

Second, and more importantly, how often do you oil? I figure these holes are taking me 7 to 10 minutes to drill but I have not timed them. I figure I am running the drill as slow as possible so not sure what that is but it is not the full 500RPM and it is not crawling. Maybe 200RPM max? I oil once every 30 seconds, a few dribbles down to fill up the hole. If I see smoke I stop, oil up and continue (Don' see smoke very often).

I ask all of this as my one neighbor erects steel buildings. He is pretty ruthless. Grabs a bit, slams pressure on it and maybe some oil if he is feeling generous. I think he has guys sharpening bits so longevity of a bit isn't foremost on his mind, more getting the holes in and building erected.

 

[Cord]

High speed steel bits for mild steel. Cobalt for stainless steel. Cobalt is very brittle and chips easily. Titanium nitride is just a coating. Works great until the coating wears off. And that doesn't take long. When the titanium nitride wears off it's just another high speed drill bit. Carbide tipped for cast iron and concrete.

2nd. I also like split point bits just to confuse you further.

 

[Sodo]

Just a note about annular cutters.

I like the annular cutters. Hougen for example. But I typically use an 18v drill, and with an annular cutter you don't have to push so hard, and you're not turning the entire plug into chips. So you can drill many more holes (by hand) with less battery power, and less effort. They are expensive, ($25 each) but very nice and they cut fast. Also they make a round hole (as opposed to starting triangular and eventually getting round if the material is thick enough). Be sure to check the depth - the set that I have cannot cut all the way thru 3/8" material, it has a depth limitation.

I've used the standard "hole saws" too, the kind with a pilot drill that you can get for about $8. These work OK for a 3/4" hole if not too many of them. The hole size comes out about 1/32nd over. $8 is not much for a 3/4 holesaw, they are a reasonable alternative, and also can be used with 18v. I drilled twelve 3/4" holes in 3/16" steel with one holesaw and its still sharp, not bad for $8.

 

[DeereMann]

Use steel bits for steel - not junky big box store wood bits. I recommend Triumph Twist Drill (Precision Twist Drill) or Norseman. It's worth the money to have one serious set of metalworking drill bits. They cut much faster than big box store junkers.

Amazon.com: drill bits - Industrial Drill Bits / Cutting Tools: Industrial & Scientific

 

[SPYDERLK]

So... First, thank you to everyone so far. Lots of great info.

As an update to the project, I was wrong. the holes needed to be 3/4 (Caught this before I drilled) and my steel is more like a thick 3/8" but my drill press runs too fast (500RPM on slow side) and the throat just didn't have the throw I needed. So I went with my large Milwaulkie Hammer Drill. Works like a charm, except for those magic moments when the bit catches and it is ripped from your hands, usually smacking you in the jaw as a friendly reminder to who is actually doing the work. Oh, I went with the normal high speed cobalt drill bit.



It brings me to my next series of questions. I want to get a speed control. JJ posted a link to a few and I see no reason either my drill press or my hammer drill would not run with this.

Second, and more importantly, how often do you oil? I figure these holes are taking me 7 to 10 minutes to drill but I have not timed them. I figure I am running the drill as slow as possible so not sure what that is but it is not the full 500RPM and it is not crawling. Maybe 200RPM max? I oil once every 30 seconds, a few dribbles down to fill up the hole. If I see smoke I stop, oil up and continue (Don' see smoke very often).

I ask all of this as my one neighbor erects steel buildings. He is pretty ruthless. Grabs a bit, slams pressure on it and maybe some oil if he is feeling generous. I think he has guys sharpening bits so longevity of a bit isn't foremost on his mind, more getting the holes in and building erected.

Not using a pilot hole are you?

 

[woodlandfarms]

1/4" pilot hole not too deep. Just a starter hole so I am centered correctly.

 

[newbury]

<snip>
Second, and more importantly, how often do you oil? I figure these holes are taking me 7 to 10 minutes to drill but I have not timed them. I figure I am running the drill as slow as possible so not sure what that is but it is not the full 500RPM and it is not crawling. Maybe 200RPM max? I oil once every 30 seconds, a few dribbles down to fill up the hole. If I see smoke I stop, oil up and continue (Don' see smoke very often).
<snip>

When I would drill down into horizontal (flat) surfaces I tried to keep a small puddle of generic machine oil.
The last several times I had to drill I was drilling into vertical surfaces (like my trailer frame), thus the regular oil quickly ran away. That's when I decided to use QUALITY chain saw oil, because it was tacky and "stayed" better. I'd dip the bit in the oil and drill for maybe 10 seconds. No smoke.