"hank" wrote in message
...

I have have a house full of double hung windows. ( actually only the
lower half raises and the upper half stays fixed) The spring has a
plastic cover on the upper half which has become brittle and needs to
be replaced. Lockwood the manufacture originally from Canada has gone
out of business

Spring balancing is non-standard. The classic mechanism
was a sash cord running over a pulley to a counterweight that
moves up and down in a channel hidden within the window frame
(reached via a mitred wood hatch.) If your Lockwood springs
break, it may be possible to retrofit the standard mechanism.

--
Don Phillipson
Carlsbad Springs
(Ottawa, Canada)