Modifying a Bezzera BZ16 head to reduce the protrusion of that damn screw

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
legrunt
Posts: 10
Joined: 9 months ago

#1: Post by legrunt »

Got myself a Bezzera BZ16. Lovely machine... except for that giant domed screw poking out right in the middle of the shower screen.
In my basket, where I could comfortably fit 18grams in before, I need to put in only 16grams now, otherwise the puck screen would be squashed by that screw and turned concave.

So I was thinking, ... if I take off the shower screen and dispersion plate... countersink drill the dispersion plate, then use a countersunk screw to gently deform the showerscreen to fit, would that enable me to use a countersunk screw which would then be flush with the shower screen? Or am I going to royally screw up something?

User avatar
hankbates
Posts: 465
Joined: 13 years ago

#2: Post by hankbates »

The parts list for a BZ16 shows a flathead screw, M5 x 16mm. Probably all you would need.
Bezzera p/n 7817001.
Some people rescue dogs and cats, I like to rescue Livias…

legrunt (original poster)
Posts: 10
Joined: 9 months ago

#3: Post by legrunt (original poster) »

Hmmmm. You are right. Parts list shows a countersink screw. But mine came with a dome head screw.
I've got a titanium countersink screw on the way. When it gets here, I'll try to fit it in to see how it goes.

legrunt (original poster)
Posts: 10
Joined: 9 months ago

#4: Post by legrunt (original poster) »

Searching for the dispersion plate online, 5285501TP, I'm getting something weird.

Look at this.
https://www.elektros.it/om/en/ricambi_m ... 501tp.html
The one on my machine looks like this.


However, take a look at this.
https://www.finecoffeecompany.com/shop/ ... older-d57/

While the part number is the same, the second one looks countersunk where it would take that flat headed countersink screw.

Looks like using a 10mm drill bit to drill a countersink on my dispersion plate would make it go from the first link's picture, to the one in the second link.

legrunt (original poster)
Posts: 10
Joined: 9 months ago

#5: Post by legrunt (original poster) »

Just to update here.

So I ended up using a 10mm drill bit to drill out the dispersion plate, not only enough to countersink the screw, but deeper cos I wanted the screw to sit flush with the shower screen. After I was done, the screw could sit in the dispersion plate deeper by about the thickness of the shower screen.

I then put the shower screen on the dispersion plate, put the screw in, and on the other side, used a washer and a small nut and torqued down with a wrench while holding the screw in place with a hex key. The reason for doing this off machine is because of the deformation of the shower screen required (it was originally flat) the screw would need to be torqued down hard, and I didnt want to scratch the shower screen, so I tightened from behind using a nut.

After deforming the shower screen enough such that the head is now flush with the screen, I found that the deformation of the screen was not just constrained to the hole around the screw, but the entire screen was slightly less convex, hence was not fitting on the dispersion plate fully flat. To remedy this, I just flipped the showerscreen down onto a soft surface (like my bed) and pressed down using the back end of the drill (holding the tip with a rag to prevent cutting myself). Pressing down hard was enough to press the general shape of the shower screen convex enough to fit the dispersion place, but still retaining the countersinking required to have a nice flat surface for the screw.

This was what it looked like originally.


This is the part I drilled out.



This is the final result.

BaristaMcBob
Posts: 275
Joined: 4 years ago

#6: Post by BaristaMcBob »

I was thinking of upgrading my shower screen too. How's the end result? Was it worth it?

legrunt (original poster)
Posts: 10
Joined: 9 months ago

#7: Post by legrunt (original poster) »

Very much so. I can use the appropriate amount of coffee grinds for the basket.

Mbonus
Posts: 140
Joined: 9 months ago

#8: Post by Mbonus »

Nice work! Looks great