Cantilever Sockets

The Canti socket size for the older Marzocchi (all before the Bomber’s) is M6, length1/length2, length overall …. <pic, drawing>

Details Canti Sockets : 

• Gewinde : M6
• Length overall : 44 mm
• Einschraublänge : 9 mm
• Aufnahmedurchmesser für Bremsarme : 7,88 mm (nach Norm?)
• Material: original Marzocchi : Stahl, brüniert
• Gewicht : 12 g/pcs (original Marzocchi)
• Marzocchi Art.-Nr.: 532592BZ>F 

The Bombers have different Canti socket sizes:

• M6 –> Marzocchi Bomber (1999), Z1, Z3 (Canti-Pin BAM), Z3 Flylight 100, DH3
• M6 x 0.75 –> Marzocchi: Z1 Wedge, Z2 (Canti Pin M-Arch), also used in
  – Marzocchi Bomber Z2 Atom Bam light
  – Marzocchi Z2 X-Fly
  – Marzocchi Bomber Z3 M80 (Mg-Arch)
  – Marzocchi Junior T

I made very good experiences with Canti sockets from Brake Stuff.
They are a bit more expensive, but are made of very good quality (stainless steel) and with excact dimensions! You will find detailed drawings on there website.
They also offer the 3-Hole Plates for the brake return spring on V-Brakes e.g. Shimano XCR V-Brake M960 a.o..