I've been using these soft stainless steel dog bowls from Walmart as knock boxes, and they work great. The rim is wide and a little soft (lots of "give"), and by tapping the shaft of the portafilter on the soft rim, the puck comes right out in one piece and the portafilter doesn't get scratched or marked up. They're $6.95, the pucks get easily dumped in the trash, and then the bowl gets rinsed out in 2-3 seconds in the sink. I thought I eventually needed a real official knock box till I actually used one: kind of a mess to clean. These bowls work really slick. I've been using the same two bowls for a couple of years (one's always clean), and I've never damaged a portafilter. Here's the link. You'll need to cut and paste:

Petmate- Stainless Steel Bowl- http://www.walmart.com/ip/Petmate-Stain...l/14244961

Yeh, my wife would be thrilled with a dog bowl on the counter!

You could paint the rim of the bowl with liquid rubber to cushion it. You could also drill a hole through both sides and put a dowel rod in it as a knock bar.

Most of my coffee prepping and drinking is before 6AM in the morning. It didn't take me but a few times using a knock box to conclude that it was one item I could do without. Takes up space, collects smelly coffee grinds and pucks, PIA to clean and too noisy at that time of the day. Most of my pucks just slide out whole anyway making it even easier to shake out in the waste can and clean. I prep my baskets over the sink so I don't need the knock box.

Bob

Still like my bumper knock box the best. Rubber base, rubber knock bar, rubber trim ring and stainless guts. Holds a lot of pucks and the rubber retards the noise when thumping a portafilter.

I'd also highly recommend the Bumper.

cannonfodder wrote:Still like my bumper knock box the best. Rubber base, rubber knock bar, rubber trim ring and stainless guts. Holds a lot of pucks and the rubber retards the noise when thumping a portafilter.

The Bumper brand has been discontinued 2 years ago (http://www.coffeebumper.com/) but the same comments are applicable to the new Cafelat brand (url]http://www.cafelat.com/[/url], still from Paul Pratt. I have the Cafelat Tubbi (the smaller one) and I'm very satisfied with it. The larger one use the same design but can hold more pucks.