Unbeliever wrote:

Michael Kilpatrick wrote:

Our builder has, much to my annoyance, fitted a mortice sash lock on a
new bedroom door and two bathroom locks on two other new doors which
are not capable of supporting unsprung door knobs. We have some nice
brass knobs to use.

[snip]

You are simply making a mountain out of a molehill - almost all mortice
latches and locks will have sufficient spring pressure to operate a simple
door-knob setup - unless the knobs are rather heavy, and something will
usually still fit anyway with minor adjustments.


No, that simply isn't true. The modest friction within the knobs (which
are small ovals, not heavy handles) appears to be far too much to return
the knobs after release. And it's clear from the literature, having now
looked it up, that some units clearly state that they are appropriate
for sprung levers/knobs only, others for unsprung ones.

It's also very simple to observe that all the old mechanisms in the
house have much stronger springs than the new ones and they were
perfectly comfortable with those knobs.

I'm just baffled as to why anybody would want to move the springs from
within the latch mechanism to within the handle itself. That's the
design decision that "made a mountain out of a molehill", as it
instantly -and obviously - means that various old handles which are not
sprung cannot necessarily be used with a lock that is only for sprung
handles.

I mean, the latch has to have a spring anyway, so the end result is that
for sprung handles you have *two* springs (or three, if both handles of
a pair are sprung) rather than just one.

Michael