SDS Drill Bits

SDS drill bits are a type of shank. The drill bit is held by the drill’s chuck and its cutting edges are positioned on one end with the shank on the opposite end. There are many types of chuck and shank varieties which do different jobs for example, giving a larger centering accuracy or providing a higher torque.

In 1975 the German company Bosch developed the SDS drill bit. The name is derived from “Steck Dreh Sitz” in German, meaning Insert Twist Stay. The term “Spannen durch System” or clamping system may also be used in German speaking countries but Bosch uses “Special Direct System” internationally for consistency and ease of understanding.

SDS shanks are helpful for hammer drilling. Sliding keyways are used in the rotational drive. The keyways open to the shank’s end which then fits with keys in the chuck. The chuck holds the smaller areas which don’t open to the end and this helps to stop the drill bit loosening and dropping out. The flat end of the shank is hit by the hammer of the drill and the shank is covered with grease to enable the bit shank to move with ease in the chuck.

The SDS shank has a spring loaded chuck meaning it is easier to chuck the bits using a simple and fast one-hand action. Moreover, the chuck and shank are excellent for drilling into concrete and stone. The chuck does not hold the drill bit solidly but allows it to move to and fro, a bit like a piston. The hammer part of the drill works to increase the speed of the drill bit only and not the larger area of the chuck. This enables hammer drilling using an SDS drill bit hugely more productive than using the other available range of shanks.

SDS bits come in four sizes namely, SDS, SDS-plus (sometimes SDS+), SDSTop and SDSMax. The type most commonly found on the market is SDS-plus offering a range of drills for stone and brick work from 5mm in diameter to 30mm in diameter. Regarding length, the shortest are usually around 110mm with 1000mm being the longest.

Handy and portable power drills usually use the 1000 mm long drill bit and it is made solely for this purpose. However a shorter drill bit needs to be used first to create the bore, usually about a 400mm long bit will suffice for this purpose. The longer drill bits are very handy for wiring installations and plumbing in already existing stone or brick housing.

The SDS drill bits have excellent hammer drilling performance and have a fast one-handed chucking operation. They are rather complex to manufacture. The “rotation stop” feature can use chiselling bits. It has a high torque transmission but suffers with inaccurate centering.

Companies that manufacture or sell these specialised tools include Makita, Irwin and Hilti. As well as SDS drill bits, there are many other types on the market for different purposes including brad point, flexible, glass, long, metal, step and tile drill bits.

Tagged with: 1000mm • 5mm • Accuracy • Bosch Drill • Brick Work • Concrete • Consistency • Cutting Edges • Diameter • Drill Bit • German Company • German Speaking Countries • Grease • Hammer Drill • Hammer Drilling • Keyways • Piston • Sds Drill Bits • Shanks • Torque

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