How to Drill Stainless Steel the Easy Way
In this blog post, we'll look at how to drill stainless steel and look at the tools and best techniques for completing this task.
We'll also look at the different types of drill bits that you can use, when to use them, and some drilling safety tips to help you comply with health and safety. This technique can be used to drill a variety of stainless steel systems, including raceway systems, cable tray systems and electrical enclosures.
Things you need to drill stainless steel
To drill Stainless Steel with ease, you will need the following:
A suitable drill bit
Drill (preferably with torque settings)
Cutting Fluid
Eye Protection
Safety Gloves
Face Mask
Note: If you only have one or two holes to drill, a standard high-speed drill bit will be fine, but it must be very sharp. For more holes, a Cobalt drill bit is recommended.
What type of drill bit for stainless steel should I use?
Coated HSS Drill Bits
If you want to invest in a drill bit that will drill a lot of holes, it may be worth investing in a HSS bit that is coated in Titanium Aluminium Nitrade. The coating is a golden color.
When visiting your local DIY store, do not be confused with cheap painted drill bits that are not suitable for drilling Stainless Steel. Look for drill bits which state 'Titanium Aluminium Nitrade' on the packaging.
Cobalt Drill Bits
These are even harder than HSS drill bits and are designed to drill hard metals including Stainless Steel.
Professional Hole Saws
Professional hole saws can be used for very large holes. They are made from a hollow cylinder with one end closed and with fittings for an attachment to a common arbor. They are manufactured from substantial steel.
The leading edge of a hole saw has a section of a sawtooth profile which will cut a hole through many kinds of material. The complete hole saw will pass right through the hole they have made. The arbor will usually take a range of saw sizes from 20mm to 80mm.
A pilot drill which is attached to the arbor will cut ahead of the main saw and keep it centered and cutting in line. A hole saw will not remove the bulk of the material - it only cuts a line around the perimeter of the hole. This type of hole saw can be used to cut circular holes in thin Stainless Steel sheets, but you must adhere to the 'Techniques for Drilling Stainless Steel'.
Unsuitable Hole Saws
The 'thin, bendy, springy' type of hole saw which has cutters that do not form a complete circle is not suitable for cutting Stainless Steel. They are easily recognizable in your local DIY store by their ability to mount a complete set of cutters on the same arbor at the same time. This type of hole cutter is not suitable for cutting Stainless Steel.
Techniques for drilling Stainless Steel
Drill slowly allowing the drill bit to do the work
Apply pressure, but not too much
Enough pressure will mean the drill bit doesn't 'skip' over the surface of the material. Too much pressure will cause the drill bit to glow red and will permanently damage the drill bit. If you apply too much pressure, the Stainless Steel may turn black and go very hard which will make future drilling quite difficult.
Use a center punch to mark the center of your hole
This will stop the drill bit 'skating' around the surface of the Stainless Steel so that the hole is drilled in the correct place and you don't scratch the surface of the Stainless Steel.
Before pulling the trigger
Before you pull the trigger on the drill, make contact with the surface of the Stainless Steel and apply gentle pressure. This will improve the performance of the drill bit.
Stopping Drilling
To stop the drilling, keep the drill speed constant and quickly remove the drill bit from the work surface.
Keep your cool
Applying copious amounts of cutting fluid to the drill tip where it makes contact with the Stainless Steel will help the tip stay cooler and sharper for longer.
Health & Safety Tips
Use a drill with a torque limiter or safety clutch
Drilling Stainless Steel may cause your drill bit to snag in the workpiece. To avoid injury, it is recommended that you only use a drill that has a torque limiter or safety clutch fitted.
Secure your workpiece
On all occasions, your Stainless Steel should be securely attached to a bench or similar work surface. When your drill bit penetrates the Stainless Steel it may snag and the Stainless Steel may attempt to rotate, which can potentially cause you injury.
Where possible you should use a fixed bench drill so that your Stainless Steel workpiece can be securely fastened to the bench.
Wear PPE at all times
Goggles and safety gloves must be worn at all times for drilling safety
Cutting Fluid Fumes
Depending on the type of cutting fluid that you use, it may be necessary to wear suitable breathing apparatus. You must follow the health and safety instructions which are supplied with your cutting fluid.
Caution - Hot Surfaces
Throughout the drilling process, your drill bit and the workpiece will get very hot and may retain the heat for several minutes after the drilling has been completed.
