# Gaggia MDF reborn - conversion to on demand style



## marcuswar (Aug 19, 2013)

Unfortunately the handle of my Gaggia Grinder (MDF) snapped off the other morning, fortunately this was AFTER grinding the beans so I still had my morning coffee while pondering what to do next.

After taking the mechanism apart to examine and hopefully repair, I decided that I'd never liked the dosing mechanism anyway so why spend money on repairing it. Instead I decided to see if I could convert it to a rudimentary style on-demand grinder.

The doser comes off very easily;

1) remove the two black rubber bungs inside the top of the hopper to reveal two screws.

2) remove the two screws in the hopper - this allows the hopper to be pulled off.

3) remove the two front screws on the top corners of the grinder in front of the hopper to allow the top cover to be removed.

4) having revealed the top of the doser mechanism, remove the centre screw to allow the small chute cover to be removed.

5) the actual Perspex bowl of the carousel is removed by removing the two screws underneath the doser mechanism. Its a bit fiddly as the arms of the portafilter rest are strategically position to be in the way. I ended up using a screwdriver bit held at 90 degrees in a pair of pliers.

6) the Perspex bowl now lifts out with the ratchet mechanism revealed underneath.

7) The ratchet mechanism and the carousel can be removed by removing the screw and washer on the left, and the bolt in the centre.









(Doser ratchet mechanism. sorry about the lens flare)

I used the top of an old Pepsi bottle (other fizzy drinks are available) to create a curved bowl style chute inside the old doser Perspex container. The chute is just shaped and held in place with some electricians tape on the back of the doser's Perspex container. The angle of the chute is not really acute enough for the coffee to drop freely without some gentle persuasion by slapping the sides of the grinder, but if the grinder is angled forward resting on the portafilter arms (45 degrees) it works quite well.

I shot a quick video of it in action ;

[video=youtube;6r_UZep3-KY]






The grinder has to be momentarily stood back up towards the end to make sure all the beans make it down into the throat of the grinder. I could probably do with making a similar mod to the hopper so that beans only go down through the top part of the hopper throat while its leaning forward.

I single dose into the hopper and then grind onto a piece of paper/divider from a chocolate box. I then whisk up any clumps with a paperclip then fold the paper and pour into the basket on the scales to make sure all beans have been ground.


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