Toller wrote:

I have 3/4" copper hot and cold pipes running through the basement. 1/2"
copper pipes run off them to below sinks and then run up to the sinks.
The problem is one that is a 3' run from the 3/4" line to below the sink.
It is now attached to a 3/4" board attached to floor joists. I want to move
the 1/2" lines so they are even with the joists; that means moving them up
about 1.5". There is no problem with the sink as it is connected to the
1/2" pipe with a flexible connector. I am concerned about stressing the
1/2" pipe or the connection to the 3/4" pipe.

Seems to me that copper ought to have enough flex to accomodate moving 1.5"
over a length of 3', but I don't want to find out the hard way that I was
wrong. Anyone with experience here? The pipes are about 25 years old, if
the matters.

I want to put in a dust collector that requires 91", and I now have only
90"! Any place I can put it has problems with heating ducts or worse.

Cut and re-fit. When I replumbed my mother's house years ago it got the
usual trunks parallel to the main beam. Each T off the trunk angled up
at 45 degrees with a short stub to a 45 degree fitting to bring it
parallel and then a short stub to a ball valve. Gets the branch line and
valve within the joist cavity and does it with a little less bend and
loss of water flow.

Pete C.