Nominal dimensions:

pusher	1.1 mm x 12 mm
shaft	3.7 mm x 8 mm

Adjusted dimensions for the first try:

1.2 mm, 3.8 mm = 5 mm

Piece thickness:

7.9 mm

Final size:

pusher	~0.8 mm x 10 mm

http://downloads.qi-hardware.com/people/werner/tmp/m1butwood.jpg