Drilling Stainless Steel
When drilling stainless steel, it is important to note that drill bits intended for woodwork cannot be used on stainless steel, as they are often softer than the steel itself. Smaller drill bits can also be challenging to work with as they are more prone to bending/breaking under pressure.
Good Practice is to use a sharp, high speed metal drill bit. HSS bits (often referred to HSS drill bits) is the minimum acceptable material – and expect them to dull quickly. These can be purchased at any hardware store, and are the most commonly used drill bits for metal applications due to their cost.
Best Practice is to use a new, sharp, 135 Degree Split Tip metal drill bit. These are the characteristics of the preferred Drill Bit. Bits of this ‘type’ come in a WIDE variety of coatings and base material – but Cobalt M35 is a very reasonable and expect them to last extremely well when used properly. These can be purchased at specialized tool/material stores, and are the most appropriate drill bits for metal applications due to their longevity (and lower cost per hole).
Once you have sourced the correct drill bit, it’s time to start drilling! Set your drill/drill press to the slowest speed (or as slow as the trigger will allow) and apply as much pressure as possible to the drill bit. Obviously, using a mill or a drill press is HIGHLY preferred.
In addition to pressure and speed, temperature is also a vital variable to consider when drilling stainless steel. In an industrial setting, lubricant/coolant is applied continuously to the tip of the drill while working with stainless steel. And tables of ‘speeds and feeds’ are referenced based on the grade of stainless and the coating/material of the bit. (…cause they are GOOD at it).
While this mightn’t be achievable in a DIY setting, it’s still important to keep your steel as cool as possible. This can be done by intermittently stopping work, dripping small amounts of oil/fluid onto your drill bit and hole. Proper cutting oil will work best for this, however even spit, WD40 or motor oil can be used in a pinch. Stopping work will also help stop heat building, and give the stainless steel time to cool (but it MAY work harden the material…).
And then there is: