"Sheldon" > wrote:
> They all unscrew, I've never seen a valve seat that wasn't removable,
> even those made more than 75 years ago were removable, why, because
> it's easier to machine a valve with removable seats.

They definitely come with integral nonremovable seats, though this is
uncommon. Making a removable seat requires machining a thread into the
faucet body, so there's hardly a savings there. Plus there's the valve seat
itself, which also requires machining a thread on it.

In a previous post, I described a nonremovable seat laundry tub faucet I had
to replace. Laundry tub faucets tend to be made very cheaply, since the get
relatively little use and don't have to be attractive.

Here's an extract from Old House Journal (10/2002) mentioning the existence
of nonremovable seats:
--
Under normal use, the washer loses its sealing ability as it ages and needs
to be replaced. If it is neglected, however, water will leak past the
washer, eroding part of the seat, which will then have to be replaced (if it
is the threaded, removable type) or resurfaced (if it is part of the faucet
body).
--

> In 2007 it's hard to believe that some diehards are
> still changing washers... tantamount to having a crank start on your
> automobile.

There are many reasons why people don't replace faucets but continue
changing washers. Two of the most common are these:

- Replacing the faucet in a bath or shower requires ripping a wall open to
do it.

- The faucet is an older design for a sink that can't be replaced without
replacing the sink itself. The standard spacings we now have for faucets are
not the same as some sinks of years gone by. My parents house, which was
built in 1952, had faucets where there were two controls for hot and cold
separately mounted at the left and right. In the center was a completely
separate spout. I have never seen replacement faucets for such a
configuration.

--
wff_ng_7 (at) verizon (dot) net