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SJS - Super Joint System

SJS - Super Joint System

SJS is a massive advance in power, safety and durability.

The design gives maximum transfer of power and torque, while minimising the wear and tear that happens with older technology. Plus it disengages under extreme loads, protecting the user and the machine.
…and it’s only inside Makita high powered angle grinders.

SJS is an advanced drive system, based on a coil spring which wraps around the internal drive spindle.
diagram showing coil spring
On start-up, the coil tightens around the spindle to produce smooth, direct and highly efficient drive from the motor to the grinder disc.
diagram showing how coil tightens
If the grinder 'grabs' or overloads the motor, the SJS is instantly disengaged by the reversed force and the drive spindle rotates freely.
diagram showing how grinder grabs
Photo of cutter in use

More Power

The Super Joint System (SJS) delivers the optimum power and torque to the grinder disc, so you get top performance.

Photo of cutter in use

More Durability

SJS means greater durability. The way SJS engages means the motor and gears are protected from shock at start-up or if the grinder grabs.

Photo of cutter in use

Made Safe

The SJS drive system is based on a coil spring which engages more gradually at start-up - and instantly disengages if the grinder grabs.