5 Steps

To Drilling Stainless Steel

How to drill into stainless steel is a commonly asked question and for many drilling stainless steel can

be a daunting task. However it can be done easily and efficiently if you follow some simple steps and

consider the following questions which all amount to keeping the drilling surface temperature as low as

possible.

Step 1. Drill bit

When drilling into stainless steel the choice of drill bit will ultimately determine how successful you will

be. Cobalt drill bits are considered the best option due to their ability to withstand the high

temperatures created when drilling harder metals. 

Step 2. Speed

Many people have a tendency to drill at as high a speed as possible assuming that the faster the drill bit

is turning the quicker it will drill the hole. This is a big mistake, particularly when drilling stainless

steel. Stainless steel is not the hardest of metals in its natural form, however as pointed out by Chip

Lawson in his piece ‘Know How: Drilling Stainless Steel’, stainless steel will ‘work harden’ fairly quickly

when heated, and one sure way to increase heat is to drill fast. Once the stainless steel is work hardened

it will become very difficult to drill.

There are many drill bit speed charts available quoting revolutions per minute, in reality not too many

people will be able to relate to these figures. Our advice would be to drill at as slow a speed as your

power drill will allow.

Step 3. Pressure

Another misconception is that maximum pressure will result in maximum results. Excessive pressure will

have the same effect as drilling at a high speed, it will cause unwanted heat build up. The best approach

is to start off with a light pressure increasing slowly until you achieve nice spiral cuts coming from the

cutting face. Once achieved do not exceed required pressure.

Step 4. Lubricant

It may seem obvious to some that when two metal surfaces are moving against each other under

pressure that lubrication is necessary. However many will drill metal without any form of lubrication. A

good drilling Lubricant will reduce the friction and assist in controlling temperature build up. There are

many types ofdrilling lubricant available including oils, sprays and pastes. Our advice would be to use

one rather than not using any.

Step 5. Take a break…

Even with a slow speed, reduced pressure and good lubrication heat build up is inevitable when drilling

stainless. It is important therefore to stop drilling from time to time to allow the drill bit to cool down.

We would recommend you do not drill for longer that 30 seconds without taking a break. As Allfasteners

say in their article ‘Drilling Stainless Steel the Right Way’ drill the material on short bursts. The larger

the drill bit size the faster the heat build up will be so this time should be reduced for larger drill bit

sizes.