Tije turning a LONDINIUM portafilter into a 'naked'

Since the standard 'naked' portafilter from LONDINIUM is excellent but a little too tight at the lower end to facilitaie the new Transparent Portafilterbasket  that Tije produced, Tije took one of my regular L1 portafilter and changed it into a naked one that exactly fits the transparent one.

Unscrewing the double spout

Double spout off. Future TPF on the right

Heating the metal to soften up the plastic handle Loctite

Softened up, the thread does not stick anymore and unscrews

PF in the lathe

Circular saw ready to start eating away

Grinding away, advancing slowly

And gone is the bottom!

Sharp edges still

Filing away the sharp edge

And ready! Perfect fit for the transparent basket

Fitted on the LONDINIUM 1 ready for action

Using Tije's Transparent Portafilter, a first video

Tije's Transparent Portafilter clip3 from Frans Goddijn on Vimeo.

Tije de Jong made this Transparant Portafilter. Here are a few first extractions with it. Sometimes at the end when the pressure drops (backflush) the puck expands surprisingly. Also, it seems a firm and level tamp helps a lot to get a delicious extraction, at least in this test setup.

Thank you Graciano (and Lore)!

My eldest daughter Lore is a midwife based in Arnhem and a while ago she helped with the birth of the third son of a wonderful couple from Panama. She told me they were active in the coffee business and I found that very interesting.

Turns out it was Mr Graciano Cruz! I never met him, missed a few opportunities when he was in Amsterdam but I have mentioned his coffee a few times already. His Los Lajones beans deliver the most exquisite coffee I have tasted so far. If you have ever been overwhelmed by the beauty of unwashed Sidamo beans, you came very close to the experience Los Lajones can give you. I'm very happy I got a hold of these beans through Kees Kraakman and Adam Craig.

When he heard that Lore's father is into coffee as well, Mr. Cruz gave her a few bags of green beans (Panama Emporium, Los Lajones natural and Los Lajones Peaberry Natural) plus one that was already roasted very light.

In the 20g IMS basket, I dosed 24g of the roasted beans, ground very fine (turning the top burr of the HG One from my most used reference 6 O'clock setting to 8 O'clock) using the LONDINIUM I pulled 25g of espresso in just over a minute. Yummmm... a delight to the last drop.

Thank you Mr & Mrs Cruz & thank you Lore!

Tije turned a la Pavoni Pro portafilter "naked"

Thanks Tije! Also for taking off the slightest bit of the "high nailpolish gloss" off the wood which now looks more like wood and not like plastic anymore ;-)

Transparent Portafilter: The Making, part 2

Today, Tije nearly finished the new Transparent Portafilter. When the sealant has hardened and some final polishing is done, it's ready for action.

Steps taken

The polished 'puck' is first covered with a transparent protective tape. Then the existing hole is drilled out to be much bigger, followed by the lathe cutting out a tiny sliver at a time from the inside out, widening the inside hole and slowly turning the 'puck' into a short 'bottomless basket' with an outside rim on the top and an inside rim on the bottom where the metal mesh bottom will be fitted.

Small disaster

Despite the utmost care and the tiniest steps taken with the two delicately sharp cutting tools made by Tije for the task of cutting out most of the bottom of the 'basket', at one point the lathe lost its grip on the basket which damaged the top rim a little, also leaving a deep scratch on the outside of the basket.

Finishing this prototype

Tije wanted to start making a new one right away but I voted to first finish this one. We have learned that this last cutting out of the bottom needs to be done by a drill, followed by careful filing. We might learn more as we move on and then, a next version can be produced even better.

Video (try HD full screen)

Protective tape around the 'puck'

Cutting the excess tape

Puck in the lathe grips

Drilling out the inside hole

Transparency shows the drill at work

The hole must be widened to leave a strong walled basket

Tije at work

Cutting, tiny step by tiny step

Needs more widening

Next, the bottom needs to be cut out, leaving a little 'lip' to support the metal sieve

Lining out the cutting tool

Polishing the inside of the wall

Wall is getting clearer

The bottom needs to go still

Tije filed out this cutting tool

Carefully cutting away

Tije at work

After the little disaster of the lathe losing grip, Tije cuts the rest using the sharp disc

Making the rim more even

Basket sitting on the sieve for size

Making the sieve fit exactly

Measuring

The sieve will fit now

Getting out the sticky goo

Goo to keep the sieve in place and seal off the rim

Goo to stick the transparent basket in the bottom of the bottomless metal basket

Fitting them together

Cleaning off the goo

The wait for the goo to harden has begun...

Transparent Portafilter: The Making, part 1

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.

Double spout Rocket portafilter

Double spout removed

Preparing to remove the handle that was Locktite-fitted

Turning the handle to come off

Handle temprarily separated from portafilter

Selecting the tool to cut the bottom out

Fitting the portafilter in the lathe

Ready to start eating away at the bottom

Cutting halfway

Tije at work on the lathe

Hole is out

Sharpening the tool to cut the rim wider

Tije working on the lathe

Filing the sharp edge of the bottomless portafilter

making the edge a little less sharp

Transparent portafilter ready, basket still intact

Trying the tool on the basket, showing me how the steel is way too hard

Instead, cutting it out with a few sharp discs on a dremel

And the basket is bottomless as well

Some filing the edge

Finishing the edges

Ready to cut a disc of acrylic

Biting carefully at the acrylic

Almost through

And like a slice of ice, it's out

Disc out

Transparent from top to bottom, milky dise, and too big still

Cutting a thread

Thread ready for the long bolt

Bolt inserted and fastened

Cutting the outside diameter to size

And it's the perfect size on the outside

Polishing, to get the "transparent" idea

And step one is ready!

Very promising... more soon