On Tue, 13 Jan 2015 11:00:57 -0500, "Mayayana"
wrote:

| With all due respect, Jerry is wrong. I've bought many pre
| bored doors and they worked fine.
| Door knob height is standard, so unless the person that
| installed the doors previously screwed them up, they will
| work.

Nothing is necessarily standard when you're
actually doing the job. If you replaced 6'8" doors
in modern door frames, in something like a recent
condo development, you were lucky that everything
lined up. If you were replacing doors in an older
house it's almost certain that you'd need to trim
the door and that nothing would line up exactly.
In most cases the striker plate wouldn't even be
similar. All the doors in my house have settled, so
none are square. They all use old fashioned doors
and hinges. They were all hung by hand more than
a century ago, at a time when there was no reason
to care that every door frame have hinges in exactly
the same spot. If I bought pre-bored/pre-mortised
doors I'd have to do a lot of filling.


That's what I was gonna say......
If the doors were being replaced into factory made frames, (which came
with a door), there may be a standard, but if the house is older, the
frames were likely made for that house, by hand, and there are no
standards. And like you said, there is settling and other stuff to
consider.

If the doors are being replaced, it's likely they are older than the
factory made ones.

In my own house, there was a door missing on a room. I had a door that
would fit the frame, but the striker was off by around 5". I used the
door, but I had to fill the old striker hole in the frame with wood
putty. Fortunately the hinges were darn near right, but even there I
used a a little putty to make up about 1/4". Some people would replace
the frame, but I'm not that picky. I was happy to just get a door on
there and not cost me anything other than my time and a can of putty.