It can be very tricky to drill holes in stainless steel tubes because of the hardness of the material, and the fact that it will progressively harden as it is worked. This will put a lot of strain on the drill bit, particularly when you consider the amount of pressure that is needed to get through the material. The stress can lead to overheating, dull the bit, or even cause it to snap completely.

Before drilling begins, it is important to choose a suitable drill bit. High speed steel (HSS) and carbide tipped bits can both be used. The bit will need to be sharp and sturdy so it can cut through the material and withstand the downward pressure placed on it. The size is also crucial to ensure that the holes are a suitable size and to allow maximum chip flow to prevent the hole from becoming clogged. It is generally best to use shorter bits to reduce the risk of deflection and snapping. In some cases it may be necessary to start by drilling a smaller hole then gradually widening it.

As well as choosing the right drill bit, the speed and the feed rate also need to be considered. Drilling too slow or too fast can lead to breakages. It is especially important to avoid low speeds when using a small diameter drill bit. Excessive feed can result in a rough, poor quality finish that will require additional work to finish. When it comes to drilling deep holes both the speed and feed need to be reduced as the bit moves into the metal to maintain the quality.

Drilling stainless steel becomes even more challenging when working with tubes because of the rounded edge. This increases the risk of deflection and means that the depth of the hole will differ at the outer edges. Some people will use a punch to indicate where a hole needs to be and make it easier to get started, but this can result in hardening of the material. As little pressure as possible should be used to indicate where holes are to be placed.

At Multiform Tubes, we have a great deal of experience working with stainless steel. Over the years we have been called upon to manufacture tubing in many dimensions and a variety of shapes. Each project has been unique, and we have put our expertise to work to ensure we deliver the highest standards at all times.  We provide a huge variety of services including tube reduction, expansion, cutting and much more, but one area we are particularly accomplished at is tube drilling.