2025-02-27 - Cleaning a Krups 75 Coffee Grinder
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I recently got a sort of defective Krups 75 coffee grinder[0] for free
to keep my other coffee grinder[1] company. With "sort of defective",
I really just mean it was so dirty that the switch couldn't be pressed
down anymore because it was completely stuck[2]. Naturally, I decided
to take the whole thing apart and clean it properly.

WARNING: This is a mains powered device. Don't open such devices if
you don't know what you're doing because they can kill you.

In contrast to my other coffee grinder, this one only has regular
Phillips screws[3] that can easily be unscrewed to remove the bottom
plate[4]. Watch out for the spring that pushes the switch up because
it falls out easily. Note that the strain relief for the cable somehow
managed to pop out of the plastic housing, so it wasn't really helping
anymore. The cutting blades can be unscrewed using the same trick with
a flathead screwdriver mentioned in my other article[1][5][6]. This
coffee grinder is more convenient because the bottom of the motor
shaft can be accessed directly at the bottom without having to move
the motor assembly to the side. There is a plastic ring underneath
the cutting blades that also has to be removed[7].

In order to remove the motor assembly, the cable holder first has to be
unscrewed[8]. The motor assembly can then simply be removed from the
housing[9]. The plastic part of the switch should remain at the side
of the housing[10], from where it can easily be pulled out[11]. It
should be obvious from that picture why the switch was stuck. The
actual switch is located on the side of the motor assembly[12]. I
cleaned the contact surfaces on the switch with isopropyl alcolhol
just for good measure.

At the top of the motor shaft, there is a felt ring, probably as a
seal against dirt coming from the coffee/spice container above. This
ring had completely hardened and a lot of dirt had built up on
it[13][14]. After removing the felt ring and the rubber piece
underneath, all the dirt on the motor shaft could also be seen[15].
I tried to remove as much of the dirt as possible and also added a
bit of grease where the shaft goes through the metal frame. I also
greased the shaft where it goes through the metal frame below the
motor, just for good measure (of course, the shaft wasn't as dirty
there since most of the dirt came from the coffee/spice container
which is above the motor).

The last part still connected to the plastic housing was the metal
container for the coffee/spices. This is one of the parts where I
actually prefer my other spice grinder[1]. That one is a bit more
annoying to open up, but the metal container can be removed easily,
whereas on this one, it is attached with metal parts that are bent
over to hold it to the plastic[16]. It's possible to remove it[17],
but those metal parts have to be straightened, which probably can't
be done very often without breaking them. To be fair, removing the
metal container probably isn't necessary very often because it's
possible to clean underneath the cutting blades without doing that,
but I wanted to give the whole device a deep clean considering
how dirty it was. As can be seen in [18], there was quite a bit of
dirt underneath the container (if it looks a bit wet in the picture,
that's because I started washing the plastic housing before I decided
to remove the metal container after all).

[19] shows all the parts after I washed them properly. One minor
annoyance is that water can get trapped underneath the button in the
top cover that's used to press the switch, but that can be removed
relatively easily because it's only held on by a clip[20][21]. I
originally thought I would have to find a replacement for the felt ring
since it had completely hardened, but hot water and soap worked wonders
to clean it[22][23]. The coffee/spice container can be reattached to
the plastic housing by bending the metal holders again[24], after which
the plastic part of the switch and then the motor assembly can be
reinserted into the housing. Before screwing on the cutting blades, the
plastic ring has to be inserted onto the motor shaft from the top[25].
One thing I don't like here is that the places where the metal comes
into contact with the plastic housing aren't really sealed very well,
so it's relatively easy for dirt to get through. This may have been
exaggerated by me not bending the metal holders of the coffee/spice
container as tightly as they originally were, but clearly dirt had
also gotten through before. For normal usage, this probably isn't a
problem, I just wanted to point it out.

Once the blades are screwed on, the bottom plate can be reattached. The
cable holder first needs to be screwed back on, making sure to put the
end of the strain relief inside the housing. Don't forget the spring
that is used to push the plastic part of the switch up[26]. Once
the bottom plate is screwed back on, the newly cleaned coffee/spice
grinder is ready to be used[27].


[0] gopher://lumidify.org/I/phlog/2025-02-27-krups-coffee-grinder/orig.jpg
[1] gopher://lumidify.org/0/phlog/2025-02-27-severin-coffee-grinder.txt
[2] gopher://lumidify.org/I/phlog/2025-02-27-krups-coffee-grinder/switch_orig.jpg
[3] gopher://lumidify.org/I/phlog/2025-02-27-krups-coffee-grinder/bottom.jpg
[4] gopher://lumidify.org/I/phlog/2025-02-27-krups-coffee-grinder/bottom_open.jpg
[5] gopher://lumidify.org/I/phlog/2025-02-27-krups-coffee-grinder/blades_unscrewing.jpg
[6] gopher://lumidify.org/I/phlog/2025-02-27-krups-coffee-grinder/blades_unscrewed.jpg
[7] gopher://lumidify.org/I/phlog/2025-02-27-krups-coffee-grinder/blades_removed.jpg
[8] gopher://lumidify.org/I/phlog/2025-02-27-krups-coffee-grinder/cable_holder_removed.jpg
[9] gopher://lumidify.org/I/phlog/2025-02-27-krups-coffee-grinder/motor_removed.jpg
[10] gopher://lumidify.org/I/phlog/2025-02-27-krups-coffee-grinder/switch_plastic.jpg
[11] gopher://lumidify.org/I/phlog/2025-02-27-krups-coffee-grinder/switch_plastic_removed.jpg
[12] gopher://lumidify.org/I/phlog/2025-02-27-krups-coffee-grinder/switch_inside.jpg
[13] gopher://lumidify.org/I/phlog/2025-02-27-krups-coffee-grinder/felt_ring.jpg
[14] gopher://lumidify.org/I/phlog/2025-02-27-krups-coffee-grinder/felt_ring_removed.jpg
[15] gopher://lumidify.org/I/phlog/2025-02-27-krups-coffee-grinder/motor_shaft_dirt.jpg
[16] gopher://lumidify.org/I/phlog/2025-02-27-krups-coffee-grinder/metal_container_removal.jpg
[17] gopher://lumidify.org/I/phlog/2025-02-27-krups-coffee-grinder/metal_container_removed.jpg
[18] gopher://lumidify.org/I/phlog/2025-02-27-krups-coffee-grinder/metal_container_dirt_underneath.jpg
[19] gopher://lumidify.org/I/phlog/2025-02-27-krups-coffee-grinder/parts_cleaned.jpg
[20] gopher://lumidify.org/I/phlog/2025-02-27-krups-coffee-grinder/switch_button_removal.jpg
[21] gopher://lumidify.org/I/phlog/2025-02-27-krups-coffee-grinder/switch_button_removed.jpg
[22] gopher://lumidify.org/I/phlog/2025-02-27-krups-coffee-grinder/felt_ring_cleaned.jpg
[23] gopher://lumidify.org/I/phlog/2025-02-27-krups-coffee-grinder/felt_ring_reattached.jpg
[24] gopher://lumidify.org/I/phlog/2025-02-27-krups-coffee-grinder/metal_container_reattachment.jpg
[25] gopher://lumidify.org/I/phlog/2025-02-27-krups-coffee-grinder/blades_plastic_ring.jpg
[26] gopher://lumidify.org/I/phlog/2025-02-27-krups-coffee-grinder/bottom_reattachment.jpg
[27] gopher://lumidify.org/I/phlog/2025-02-27-krups-coffee-grinder/final.jpg