A modular kitchen appliance, comprising: a powerhead having a motor with an output shaft; a grinder attachment , the grinder attachment having a housing and a power coupling capable of connecting to the output shaft; a blade assembly configured to be releasably connected to the power coupling , the blade assembly having a blade for cutting, and including a transmission axle to which the blade is fixedly connected, the transmission axle configured to be releasably connected to the power coupling to transfer power to the blade ; a cup for holding material to be cut, the cup being attachable to the blade assembly and having a threaded portion to allow the cup to be screwed onto a corresponding threaded portion on the housing of the grinder attachment ; and wherein the blade is operational only when the cup is attached to the blade assembly ; characterized in that : the blade assembly includes a blade cover at least partially enclosing the blade , the cup being attachable to the blade cover ; the housing of the grinder attachment includes a ledge for retaining a plate within the housing , a spring being located between the plate and the housing for biasing the plate , the plate configured to bias the blade cover away from the power coupling in a direction in which the transmission axle is detached from the power coupling ; and with the blade assembly attached to the cup , the combined cup and blade assembly are configured to be screwed onto the housing of the grinder attachment , and the appliance is configured such that as the blade cover moves upward within the housing , it pushes against the plate , which is biased by the spring , until the transmission axle engages with the power coupling . a powerhead having a motor with an output shaft; a grinder attachment , the grinder attachment having a housing and a power coupling capable of connecting to the output shaft; a blade assembly configured to be releasably connected to the power coupling , the blade assembly having a blade for cutting, and including a transmission axle to which the blade is fixedly connected, the transmission axle configured to be releasably connected to the power coupling to transfer power to the blade ; a cup for holding material to be cut, the cup being attachable to the blade assembly and having a threaded portion to allow the cup to be screwed onto a corresponding threaded portion on the housing of the grinder attachment ; and wherein the blade is operational only when the cup is attached to the blade assembly ; the blade assembly includes a blade cover at least partially enclosing the blade , the cup being attachable to the blade cover ; the housing of the grinder attachment includes a ledge for retaining a plate within the housing , a spring being located between the plate and the housing for biasing the plate , the plate configured to bias the blade cover away from the power coupling in a direction in which the transmission axle is detached from the power coupling ; and with the blade assembly attached to the cup , the combined cup and blade assembly are configured to be screwed onto the housing of the grinder attachment , and the appliance is configured such that as the blade cover moves upward within the housing , it pushes against the plate , which is biased by the spring , until the transmission axle engages with the power coupling . <EOS>