by HB on Tue Aug 09, 2011 11:08 pm
The Rancilio commercial portafilter old/new style will fit, as will just about any 58mm portafilter listing "E61" among its compatibility list. I prefer the Rancilio because of its solid heft, but the OEM bottomless portafilters are nice too because there's no brass exposed.
PS: The La Marzocco portafilter fits, but will lock in at 7 o'clock instead of 6 o'clock. If that really bothers you, replace the grouphead gasket with one 0.5mm thinner or file down the portafilter's ears.
Dan Kehn