Portafilter Pressure Gauge

This is how I made my portafilter pressure gauge.

I used a portafilter with a threaded exit hole from an old Krupps Gaggia, which is an older model of the Gaggia Baby.

I bought this liquid filled pressure gauge, from Amazon
200 PSI Liquid filled Pressure Gauge

I bought a few parts from Home Depot
The most important one is a 3/8” Female Pipe Tee, Watts Part number A-758.

Here is a pic of the Tee, attached to the portafilter, with the valve also attached to it.

I also bought a couple of 3/8” male (MIP) to ¼ female (FIP) reducers.

The gauge screws into a reducer, which screws into the Tee.

The guage has an 1/4" male NPT thread on the bottom, reducer is on the right.

This pic shows the bottom of the gauge, with a of 3/8” male to ¼ female reducer on it.

I also bought a valve, I think I found one rated to about 180 PSI, at a local OSH (hardware store). It had ¼ threads, so I used a reducer there also.

One thing I found is that hardware stores have different names for NPT threads.
From Wikipedia
Sometimes NPT threads are referred to as MPT ('Male Pipe Thread'), MNPT, or NPT(M) for male (external) threads; and FPT ('Female Pipe Thread'), FNPT, or NPT(F) for female (internal) threads. An equivalent designation is MIP (Male iron pipe) and FIP (Female iron pipe).

I think Home Depot calls them MIP/FIP, and OSH calls them MPT/FPT, but they were all interchangable.

Here is a pic of the whole thing put together.

And, it seems to work fine.  There are a couple little leaks, which I could probably fix, but it doesn't effect its operation.  I open the valve just a little, so the water trickles out when the pump is on, and I was able to set my machine to 9 bar easily with this gauge.

Randy