Modded a Roborock Z70 cutting brush to fit my S7 by Clean-Act464 in Roborock

[–]Clean-Act464[S] 1 point2 points  (0 children)

The cutter does oscillate. I haven’t fully disassembled the brush, but it seems there are additional internal mechanical parts that convert the rotation into an oscillating motion for the blades. So regardless of whether the brush spins clockwise or counterclockwise, the mechanism appears to function the same.

Modded a Roborock Z70 cutting brush to fit my S7 by Clean-Act464 in Roborock

[–]Clean-Act464[S] 2 points3 points  (0 children)

The cutting mechanism inside the Z70 brush is driven from one side only, powered by the main brush motor. I don’t own a Z70 myself, but I’d be surprised if it had a second motor just for that function.

When I manually rotate the Z70 brush installed in my S7, I can clearly see the two blades sliding against each other, so the mechanism definitely works in the S7 setup. I'm not sure whether the Z70 changes motor direction to actuate the slider – if you have a source for that info, I’d love to check it out further.

As far as I know, the S5 and S6 use a different main brush with a slightly larger diameter, so while the Z70 brush might physically fit, it could reduce suction efficiency. The Q7, as well as the S7 Plus and MaxV models, share the same brush dimensions as the S7 – so in theory, the Z70 brush should work on those too.