Sometime ago I posted about a problem I was having with the basket being very firmly stuck on the filter head on my Elizabeth machines. It happened mostly on one I have in UK but also occasionally on the other in France. Both use VST 18G baskets.
It seems to happen mostly after the machine has heated up with the portafilter in place so I assume that differential expansion of the brass parts of the filter head and portafilter and the SS basket contribute to the problem.
Initially I thought the problem was caused by the inside of the basket binding on the brass diffuser plate which might have moved slightly off centre when refitted. After I got back here (France) in September I tried to improve the problem by gently rubbing down the brass disc (M5 bolt through the hole and fit into a drill) with 120 grit and then polishing with 600grit W&D. This didn’t help after a couple of goes so a further look at the portafilter with the basket in it revealed that the portafilter was just slightly out of alignment with the basket so one side of the basket edge was closer to the side of the portafilter. Checking the basket alone in the filter head suggested it was quite a close fit so I have now ground a little off the edge of the rim and this has improved the clearance a bit.
I will report back on the result.
PS Dave’s suggestion that it will usually release if the portafilter is wiggled as it is released didn’t work very well as the basket was very firmly stuck.