Each owner of a hammer drill sooner or later understands that the functionality of this universal power tool directly depends on the set of nozzles, the choice of which directly depends on the design of the cartridge to which this equipment is attached. The information in this article will help beginners and remind professionals of what types of restraints exist today, as well as how to make the right choice.
Let’s start with the fact that a perforator is by nature an impact machine that does not drill, but drills holes using the cutting part of the nozzle while rotating it. The collet clamping mechanism used in drill clamping devices is not suitable in this case due to very high loads. Therefore, in order to securely fix the equipment of this power tool, it was necessary to develop a unique chuck with a special shank, which has special grooves for centering and preventing rotation of the nozzles.
The evolution of this structural element of the hammer drill has been quite active, but today the SDS (steck-dreh-sitzt) type pliers developed by Bosch are considered the most reliable. If translated from German, this sentence sounds like “insert-turn-plant”.
It is this expression that almost completely describes the principle of operation of a modern cartridge for a perforator:
- we press on the protective cover to remove the locks in the form of slots and locking balls / rollers, then insert the nozzle rod with special grooves into the hole of the clamping device;
- we release the cover and slightly turn the snap until a slight click, which “informs” the owner of the power tool that the mechanism of the device has been successfully fixed (the splines and balls are in the shank grooves) the drill, drill press, etc.;
- we try to remove the nozzle from the cartridge to make sure it is properly attached;
- removing the tool from the tool is carried out in the reverse order (press the protective cover and pull out the nozzle).
Thus, the most common type of cartridge with which modern models of rotary hammers are equipped is not only quick-clamping, but also quick-detachable when working with equipment. At present, there are several varieties of SDS-type pliers, each of which has its own characteristics.
In addition, all existing pliers for punches can be divided into two large groups. Fixed cartridges are considered more reliable. But the removable chucks can be quickly replaced by combination chucks with a ring gear (key) or a quick-release collet if the owner intends to use the tool as a drill.
Which one to choose
The final choice of an SDS chuck for a hammer drill depends on the operating conditions, as well as the design features and power of the power tool:
- plus – ideal for “light” models designed for home use and construction work and the use of nozzles with a diameter of 4-32 mm.;
- max – usually used with more powerful power tools with professional equipment, the diameter of which can reach up to 60 mm.;
- top – outdated fasteners found exclusively on old semi-professional models;
- fast – a chuck specially designed for Bosch tools of the Uneo line with a special locking mechanism;
- hex – a special modification for a powerful tool for working with a chisel, pike and large drills;
- the spine is a Chinese development with a slot mechanism for fixing nozzles for nozzles with a special seal at the end of the rod, due to which shock work takes place.
So, for the vast majority of hammer drill owners, the SDS-plus type cartridge will be the best option. It is better for professionals to pay attention to models equipped with SDS-max clamps. After all, all other modifications of the SDS series devices are either outdated or designed to solve specific problems.
Fixed cartridges are suitable for power tool owners who use their powerful unit primarily to “groove” concrete and other high strength materials. The removable clamps significantly increase the speed of work in cases where the operator must constantly change the nozzles of the drill. True, in this case, the owner of the tool will also have to purchase a collet-type combined chuck.