Stainless steel group in 2024

This is a repost of my answer on HB:

jasongcasale on Home Barista asked:

My question is about the internal group head itself that these parts connect to.

I know it is still brass.When will it be switched out for stainless steel and what is the rev number when this will happen with targeted date..

As of v1.45 (coming in July 2023), in the group we'll have a top part that is brass, and the two parts below it will be PPS plastic.

As of v1.46 (coming in July 2024), the top part of the group will be stainless.The casting process can take a long time to get right, and supply chains are really slow currently, to make new designs.

When we do go stainless for the top of the group head, we'll also have a different kind of heater on it, moving off the cartridge heater that we use for the brass parts, to a flat “thick film” heater (picture above).

This lets us remove a lot of metal off the group, which we need to do in order to continue to have a fast warm up time. Stainless is much less heat conductive than brass, so we needed to find a way to remove mass in order to still heat in 4.5 minutes.

The main advantage of going from brass to stainless for us is one of cost.  CNCed brass is very expensive to make with the precision we need.  Cast stainless, then drilling out the precision areas, is much less expensive.  The removal of worrying about lead is a nicety too, but we source our brass well and for the past several years the SGS tests have had “no detectable lead”.