Friday, January 4, 2013

The Rancilio Silvia Screw Mod

How to change the ”frankenstein” brewhead screw on your Silvia

Every Rancilio Silvia owner knows about the problem, with the brew head screw. The gigantic screw leaves very limited space for dosing ground coffee to the basket. It is my experience that you can only dose up to 15 g. ground coffee with the original screw in the brew head. 

When looking around coffee forums all over the world, this issue is the most common in threads about Silvia. On the basis of that fact, I have made a how to guide to change the screw. 

This was my very first modification to my Silvia. I made it rather early on because of the constant headache of channeling, because of the overdose. It is quite easy, even with limited tools and knowledge/”handiness”.

The purpose of this mod is, to get the shower screen bolt aligned with the shower screen, to avoid channeling happening because of the bolt pressing a hole in the puck, when dosing just a little too much.

So here goes:

Parts to purchase

5x16 mm countersink bolt (stainless is preferred)
usually costs about 3-5$ 

Counter sinker, matching the angle of the 5 mm bolt  

Remove the original hex screw. Disassemble the water dispenser and shower screen from the brew head. At this point you should have these parts at your table:

Shower screen  

Water dispenser
Hex screw

At this point you are about to countersink the water dispenser. You need a proper counter sinker with the right angle matching your new bolt. If you can get to a drill press, that is much easier and accurate, but not at must! If you only have a vise and simple drill, like most people, this is what to do. 

Put the dispenser in the vise (put it between two pieces of wood, this way you won’t damage the dispenser), and start countersinking the dispenser. It is very important that you keep it in a straight angle. As you go on, stop to check the depth. When the bolt is about 1 mm below the surface you are done. 

Now you need to adapt the shower screen, to the new shape of the dispenser. This can be done in two ways. First and easiest way is simply to buckle all the parts back in the brew head. The other more need and gentle way (preferred), is to press the parts in a vise, adapting them to each other before assembly. Its easy.

Take a socket wrench top fitting inside the edges of your new bolt. Do the same Thing on the other side at the dispenser. This way the bolt Can move freely, the parts can be pressed together to adapt and shape, to fit each other. 
Tighten the vise slowly against the wrench tops, at this point; the natural shape of the bolt should create a conical shape in the shower screen. Stop tightening when the surface of the bolt and the screen are aligned. 

Assemble the parts to the brew head and start shooting. You should get more space between the puck and screen. Giving you larger oppurtunity to dose up and get better shots with the standart basket. 

Questions Can be asked in the commentfield or at

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