In my former life as a machinist, I encountered the need to drill holes in steel.
Important considerations and steps:

1. Tool steel, try T-15 or get carbide tipped bits for hard steel. Look for them in industrial supply, not Home Depot. These are not cheap, but what you need to do the job. I suggest only trying carbide if you work harden the holes by getting them too hot. T-15 should do the trick and will cost 10 to 15$ for the larger size bits. For general use get a quality set of "gold plated" bits. This is really a coating of Titanium Nitride applied by vapor depositing.

2. Coolant, yes you need coolant/lubricant. Water based is best in this case as it will help to remove excess heat from the tool bit. Use a spray bottle that you can adjust to a solid stream. A helper runs this. If working on a vertical surface some of the thicker coolants will work, but you must keep brushing it on as the chips pull it away. Does not cool as well as water based coolants.

3. RPM, VERY VERY important. Small diameter drill bits require higher speed. Larger diameter bits require slower speed. Too fast and the drill bit just turns blue and is destroyed.

4. Step drilling is the only way to go using a hand drill. Don't drill all the way through with the second to final bit. Drill just far enough to open the back side up to the diameter of the flat on the final drill bit. This helps to keep it from grabbing.

5. Use an "ole man", this is a pry bar made from a 2x3 board about four feet long. Anchor the end of the bar to a solid structure and about 6" from the end pry down on the back of the drill motor. This allows you to apply constant, even force to the drill bit.

6. Center punch, and then spot drill. The diameter of the of the spot should not be greater in diameter than the final drill size. This allows the cutting edges of the flutes to cut properly. Get your spot drill, or center drill from the same industrial supply as you get your better drill bits.

7. Pilot drill size should be the same size as the flat of the drill point plus ten to fifteen thousandths of an inch.

8. Set the proper drill speed for the size drill you are using. Apply coolant the entire time you are cutting. Apply pressure until the the chip starts to curl out in a spiral. Do not "Peck" drill as this constantly unloads the cutting edges thus causing them to wear. Keep the pressure constant until the bit breaks through. Keep the coolant constantly applied, as this removes the heat and applies some lubrication to the bit. The coolant and the chip remove heat from the hole. This is a good thing.

9. The amount of pressure you apply with the ole man is dependent on drill bit diameter. Larger bits require more force to push them through the metal. Seek to achieve chips which curl out like spiral pasta. Do your best to keep pressure constant so the cutting edges stay buried in the metal. This keeps the edges cool so they don't burn up.

10. Color of the chips is important. If the chips are bright blue shading to grey in color, the drill is turning too fast or you have not applied enough pressure to the drill bit. Seek a light blue color as that is appropriate for drilling steel.

I hope this is of help. If I had to choose speeds, I would tend to choose slightly lower speeds as this keeps from burning up the drill bits. Also always keep drilling pressure on the bit. If you just let it spin in place, it burns up!

RED ALERT

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2005 Titan KC SE, Helwig, True-Track, ARE MX Canopy

This is worth the time to read. Thanks Red!

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Drilling holes is a complex task. Unfortunately, it is considered the lowest task in the hierarchy of a Machinist's skills. Still, drilling holes is often left until the major machining tasks have been completed and an improperly drilled hole can scrap out a complex component with many machining hours already invested in it.

After re-reading it, I realize I made some omissions and I'll fill those in soon.

Red

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2005 Titan KC SE, Helwig, True-Track, ARE MX Canopy