What is a hammer drill?

Speaking of electric hammer drill bits, let’s first understand what is an electric hammer?

An electric hammer is based on an electric drill and adds a piston with a crankshaft connecting rod driven by an electric motor. It compresses air back and forth in the cylinder, causing periodic changes in the air pressure in the cylinder. As the air pressure changes, the hammer reciprocates in the cylinder, which is equivalent to using a hammer to continuously tap a rotating drill bit. Hammer drill bits can be used on brittle parts because they produce rapid reciprocating motion (frequent impacts) along the drill pipe as they rotate. It doesn’t require much manual labor, and it can drill holes in cement concrete and stone, but not metal, wood, plastic or other materials.

The disadvantage is that the vibration is large and will cause a certain degree of damage to the surrounding structures. For the steel bars in the concrete structure, ordinary drill bits cannot pass smoothly, and the vibration will also bring a lot of dust, and the vibration will also produce a lot of noise. Failure to carry adequate protective equipment can be hazardous to health.

What is a hammer drill bit? They can be roughly distinguished by two handle types: SDS Plus and Sds Max.

SDS-Plus – Two pits and two grooves round handle

The SDS system developed by BOSCH in 1975 is the basis of many of today’s electric hammer drill bits. It is no longer known what the original SDS drill bit looked like. The now well-known SDS-Plus system was jointly developed by Bosch and Hilti. Usually translated as “Spannen durch System” (quick-change clamping system), its name is taken from the German phrase “S tecken – D rehen – Safety”.

The beauty of the SDS Plus is that you simply push the drill bit into the spring-loaded drill chuck. No tightening required. The drill bit is not firmly fixed to the chuck, but slides back and forth like a piston. When rotating, the drill bit will not slip out of the chuck thanks to the two dimples on the round tool shank. SDS shank drill bits for hammer drills are more efficient than other types of shank drill bits due to their two grooves, allowing for faster high-speed hammering and improved hammering efficiency. In particular, hammer drill bits used for hammer drilling in stone and concrete can be attached to a complete shank and chuck system made specifically for this purpose. The SDS quick release system is the standard attachment method for today’s hammer drill bits. Not only does it provide a quick, easy and safe way to clamp the drill bit, it also ensures optimal power transfer to the drill bit itself.

SDS-Max – Five pit round handle

SDS-Plus also has limitations. Generally, the handle diameter of SDS Plus is 10mm, so drilling small and medium holes is not a problem. When drilling large or deep holes, insufficient torque can cause the drill bit to get stuck and the handle to break during operation. BOSCH developed SDS-MAX based on SDS-Plus, which has three grooves and two pits. The handle of the SDS Max has five grooves. There are three open slots and two closed slots (to prevent the drill bit from flying out). Commonly known as three grooves and two pits round handle, also known as five pits round handle. The SDS Max handle has a diameter of 18 mm and is better suited to heavy-duty work than the SDS-Plus handle. Therefore, the SDS Max handle has stronger torque than the SDS-Plus and is suitable for using larger diameter impact drill bits for large and deep hole operations. Many people once believed that the SDS Max system would replace the old SDS system. In fact, the main improvement to the system is that the piston has a longer stroke, so when it hits the drill bit, the impact is stronger and the drill bit cuts more efficiently. Despite the upgrade to the SDS system, the SDS-Plus system will continue to be used. The SDS-MAX’s 18mm shank diameter results in higher costs when machining smaller drill sizes. It cannot be said to be a replacement for SDS-Plus, but rather a complement. Electric hammers and drills are used differently abroad. There are different handle types and power tools for different hammer weights and drill bit sizes.

Depending on the market, SDS-plus is the most common and typically accommodates drill bits from 4 mm to 30 mm (5/32 in. to 1-1/4 in.). Total length 110mm, maximum length 1500mm. SDS-MAX is typically used for larger holes and picks. Impact drill bits are typically between 1/2 inch (13 mm) and 1-3/4 inch (44 mm). Overall length is typically 12 to 21 inches (300 to 530 mm).