The faucet for our water filter broke and the new one had different plumbing than the old one. Rather than redo all the connections I made an adapter to go from the faucet (7/16”-24 UNF for a 1/4” compression fitting) to the tubing (3/8” compression fitting)
A piece of “medical grade” Pomalux Acetal Copolymer.
Drilling for the tap.
Tapping (under hand power…)
Drilling the rest of the way through 1/4”
Flipped in the chuck and turned down to 3/8” diameter for the compression fitting.
Milling a hex so I can get a wrench on it.
The finished adapter.
In place under the sink.
The new faucet on the sink. The picture makes me think I need to tear apart the whole kitchen counter.
Anyway, no need to drive to the hardware store, although I was lucky (or a good hoarder) to have the 7/16”-24 tpi tap on hand. It isn’t common.