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.
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
Delicious cup: all the work was well invested! At the end of the previous blog about the pressostat and PID working together , I mentioned that I would like to clean up the xmas tree of wires and have as few cables and probes as possible to visually disturb the classic design of the La Pavoni. Getting rid of the probe that was fastened with copper tape to the top of the brew group was a priority. I wanted to hide a new probe in the cooling fin as close as possible to the brew group. This morning I asked Tije if he could do that. He would need to drill a straight hole of 3mm diameter in the 4mm inner ring of the cooling fin that sits as a tight clamp around the brew group. Always the optimist, Tije set to work: First, Tije made a piece of aluminum to fit the inside of the ring. Drilling a thin hole straight through the curved aluminum, if possible tangentially going through the inside of the ring to touch the brew head directly, you need the support of the temporary insid...
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