This special version allow to stiffen the head.
For this version we have to know exactly the dimensions of the head of the machine.
The positioning block is substitute by the flange "F" and the ring "Q". The dimension "X" should be done to allow play between the taper and the centering shaft, you can fit this dimension by losen the screw "Z", that is inside the taper. When you have adjusted the dimension "X",
tighen the screws "V" to lock the head; after this operation put the taper pin "P" on machine's frame.