Several people and companies have asked Stephen Sweeney if he could make them one or more specimen of his Transparent Portafilter but he told them it's way too much work. Tije, in Amsterdam, made one for the La Pavoni and after he finished his version, he understood why Stephen has so far declined most requests.
Still, Tije was willing to make me another one that would fit in most current commercial group portafilters, like my Rocket E61 and the LONDINIUM lever machine.
Tije agreed to let me see "the making of" the TPF and allowed me to take many pictures and a few video clips. I post them here so others who would like to build their own can watch and learn.
It is a great pleasure to see Tije at work. Calm, anticipating all the next steps to take, he prepares his tools, sometimes cutting and filing tools to make them best for the task he has in mind. He knows his materials and while working, explains how steel behaves, how much easier brass is to work with and how acrylic can behave like metal, glass or treacherous putty, depending on your angle of attack.
First, Tije turns a two spout Rocket portafilter into a wonderful
naked portafilter. Then he takes a deep basket and takes out the bottom, leaving a little lip to support the top rim of the transparent filter basket. Next, he drills out a solid round slice of acrylic. He drills a hole through it, turns a thread through it and fastens a long bolt through it. One end of the bolt is fastened into the lathe, the other side is fitted with a little sharp hole to fit the cusp of the lathe, keeping the acrylic disc perfectly still around the axis. Then he turns and cuts the outside of the disc to the size he has in mind, leaving the lip to fit the metal basket. He polishes the disc so you can begin to see why the filter basket will be called
transparent...
In
Part 2 Tije will show us the rest.
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| Double spout Rocket portafilter |
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| Double spout removed |
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| Preparing to remove the handle that was Locktite-fitted |
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| Turning the handle to come off |
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| Handle temprarily separated from portafilter |
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| Selecting the tool to cut the bottom out |
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| Fitting the portafilter in the lathe |
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| Ready to start eating away at the bottom |
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| Cutting halfway |
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| Tije at work on the lathe |
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| Hole is out |
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| Sharpening the tool to cut the rim wider |
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| Tije working on the lathe |
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| Filing the sharp edge of the bottomless portafilter |
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| making the edge a little less sharp |
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| Transparent portafilter ready, basket still intact |
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| Trying the tool on the basket, showing me how the steel is way too hard |
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| Instead, cutting it out with a few sharp discs on a dremel |
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| And the basket is bottomless as well |
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| Some filing the edge |
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| Finishing the edges |
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| Ready to cut a disc of acrylic |
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| Biting carefully at the acrylic |
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| Almost through |
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| And like a slice of ice, it's out |
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| Disc out |
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| Transparent from top to bottom, milky dise, and too big still |
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| Cutting a thread |
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| Thread ready for the long bolt |
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| Bolt inserted and fastened |
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| Cutting the outside diameter to size |
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| And it's the perfect size on the outside |
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| Polishing, to get the "transparent" idea |
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| And step one is ready! |
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| Very promising... more soon |
