SDS-Plus System

"SDS-Plus" or "SDS Plus"

SDS refers to the original system developed by Bosch in the 1970s, with a 10 mm shank and two open slots for axial movement plus retention features.

SDS-Plus (also written SDS+ or SDS Plus) is an improved version of the original SDS, featuring a 10 mm shank with four slots (two open and two closed) for better torque transmission, durability, and hammer performance. It became the dominant standard.

The SDS system excels in tools that deliver strong hammering action for masonry, concrete, and stone work, where the bit needs to slide axially while rotating. Standard cordless drills or regular hammer drills typically use keyed or keyless chucks instead. SDS bits are rarely used outside rotary hammers, except with adapters.

The SDS Plus system uses a pull collar chuck. Pull the ring back to open it. Insert the bit shank. Release the ring. Steel balls lock into shank slots for retention. This allows axial slide for hammering plus rotation via drive flats.

• Common sizes: SDS Plus shank is always 10 mm diameter. SDS Max uses 18 mm.
• Terminology: SDS Plus chuck, shank slots (open and closed), rotary hammer, collar ring.