What is the best metal drill bit?

One of the most frequently asked questions refers to the best metal drill bit.

The best answer probably is:” The best metal drill bit is the one that suits your purposes best.” However, this is probably not terribly enlightening so in this article we will look at metal cutting drill bits and hopefully shed some light on the topic so you can make a better informed decision.

In all honesty, this question is made more difficult as it assumes there is only one type of “metal” but this is patently untrue. Metals come in a variety of types, from soft alloys, aluminium, stainless steel, titanium and cast iron to name a few. So the best metal drill bit depends largely on what you are going to be cutting through.

Most of the home handy person drill sets available on our site come with a selection of bits that meet most hobbyists needs. This will include a selection of HSS [high speed steel ] bits as well as those for wood and masonry. If your primary target for drilling holes is plastic, leather, fibreglass, wood or aluminium then the HSS drill included with the drill set will serve fine. If you did not buy a drill set, then look for an HSS kit that contains about 10 of the most popular sizes. This should see you through most of your jobs, and if, sometime in the future you do need to drill through the occasional hard steel or iron, then you can always pick up a specialist bit for that job.

So, what are the bit options for hard steel?

When two pieces of material are rubbed together, the harder material will wear away the softer one. This is part of the principle of a metal drill bit. Now, if both the drill bit AND the material are made of steel, then the harder material will win. If you are set on making a hole and not wearing away your bit, you need your bit to be the harder of the two. In most cases the HSS bits will not be successful against hard metals, at least, not in the long run, they will heat up and lose their cutting edge very quickly. You will also heat up and likely lose your temper.

In this case we are looking at either titanium or cobalt bits, both considerably harder and more heat resistant than the basic HSS bit. Both titanium bits and cobalt bits cost a bit more than basic HSS bits in the short term, but represent better value long term. If push really comes to shove titanium drill bits are harder and will outlast a cobalt bit but a titanium metal drill bit can NOT be resharpened whereas a cobalt bit can.

So, at the end of the day it really does come back to you and what you want to do with your drill bit. If, like most home renovators you don't foresee the need to cut holes into cast iron, stainless steel or titanium spaceships then the HSS drills that came with your drill will do fine. Otherwise, spend a little more cash and invest in a titanium or cobalt bit.
But remember, even the best tool needs love and attention so treat your bits with care and they will serve you accordingly.