Q&A for How to Drill Steel

Drill bits that are titanium coated are not typically good for steel; instead, they work better on softer metals. However, cobalt alloy bits that contain at least 5% cobalt or tungsten carbide bits are best.

For faster drilling, use a drill press rather than a hand drill. However, it’s still important that you set the drill to the appropriate speed based on the type of metal and the size of the hole you’re trying to make. Consult your user’s manual to select the correct speed.

Use a sharp cobalt drill bit that’s designed to cut steel. Make sure the metal you’re drilling is held securely in place (e.g., with a vise), and never try to drill a piece of steel while holding it in your hand. Use low speeds and make sure the bit and metal are well lubricated with oil (such as 10W30) to prevent overheating. Always wear appropriate safety gear, such as work gloves and safety glasses.

Unlike wood drill bits, metal bits don’t have a spar at the tip. Instead, the tip is cut at a gentle angle. Metal bits may be black, gold, or coppery in color.

You will need a good center punch, and make absolute certain you get dead center. Put a good indentation in the broken bolt. If it's a right-hand thread you will want to find a left-hand drill bit. By using the left-hand bit as you drill you stand a good chance of it grabbing the bolt and it unscrewing the bolt for you, assuming it was the correct bolt and not installed with semi-permanent Lock Tite. If that does not work, get a good easy out and drill the hole to the size for your easy out, but don't break the easy out off in the bolt; if you do, you will be pretty much screwed. Next just to keep drilling bigger till the bolt is paper thin and dig it out. Be patient.

The holes in bathtubs are formed with a flat recessed edge to ensure the drain sets flat and securely so it won't leak. Making the hole larger would assuredly make it leak. Use a drain kit that matches the hole already in your tub.

Your drill bit is dull. There is no reason why you cannot drill into the steel studs underneath a sheet rock wall. Also check your screws, make sure they are hardened sheet metal type screws and not wood screws.

Accurately measure and mark the position to be drilled. Center pop the position very lightly, then check for accuracy. Then give a heavier center pop mark and check again. If the hole has to be 100% vertical use a drill stand. A high-speed drill should be used and usually dark blue in color. Start with the smallest drill possible. Select the optimum speed for your drill bit. Increase the hole size in stages. When the hole size is reached use a de-burring tool to clean the edges.

Most drill bits were not made to be sharpened. If you still think that you can, a grinder is really your only option.

Yes, preferably using a stronger (harder) drill bit to remove the broken one.

It won't affect the paint more or less than at a higher temperature as long as the paint has cured at least 30 days if it's new.

By gradually using larger drill bits or a specific cutting tool the size of your desired hole.

You would need tools made of tungsten carbide to drill it. They are expensive (compared to HSS ones) and they are extremely brittle, so you need to have caution using them or you will break a chip from your tungsten carbide drill. Of course, you could anneal th.e steel to make it a bit easier to work with (and be able to drill it with a common HSS drill-bit).