As any of you who have tried to take apart a mazzer doser (Dan included) know, the lower vane is probably the hardest part to take off on the mazzer Doser.
After removing the doser from the body, and removing the bottom piece (with the thwacker):

The first step is simple, knock out the pin that keeps the bolt from spinning.

The next step is where most people (including myself at first) go wrong. Since the bolt is screwed in the lower doser vane, you need to hold the lower vane and turn the bolt with a 12mm socket.

The first thought that comes to mind is to stick something into the hole where the grinds fall, to keep the vane from spinning, while applying superhuman strength to the ratchet connected to the bolt.

The problem is that these vanes are designed to sweep coffee into a hole, not to hold 200+lbs of force.

AND THEY BREAK! They are not cheap to replace either!!

So here is the proper way to remove it (with 0 chance of breakage ZERO!!)

Step 1: Take pliers (long needle nose work great) and hold the golden gear and the inside wall of the dispensing chute:


Here is a better view:


NOTE: YOU ARE NOT HOLDING THE VANES!

And then ratchet away:


With this technique, you are holding the golden gear from spinning and not the vanes, so there is no pressure on the vanes. The golden gear is quite thick and will definitely not break.

Enjoy... Now you guys have no excuse not the deep clean your mazzer... believe me there is a lot of stuff there!

Full Disassembly guide here: http://www.monkeyfaq.com/mazzer

@nostick:

are you sure you are doing it right?

I have disassembled 7 mazzer grinders using this technique and have had 100% success on each using the technique described above.

(I only broke one using the hammer in the grind chute pictured here: http://www.monkeyfaq.com/mazzer/doser.html) but luckily had a spare


Are you sure you are gripping very tightly with the pliers? maybe try having one person hold the pliers while you twist the bolt? I am surprised that yours is stuck sooo tight. I have had some that were very tight, where I needed to get a helper to hold the pliers for me, but this method works 100% of the time.

If your bolt is still stuck after the two-person method.. then try soaking it in WD-40 or something similar (you'll need to clean it well after though because wd-40 is clearly not food safe)